[PATCH v4 00/43] arm64: Support for Arm CCA in KVM

[PATCH v4 00/43] arm64: Support for Arm CCA in KVM

[Steven Price]

This series adds support for running protected VMs using KVM under the
Arm Confidential Compute Architecture (CCA).

The related guest support was posted[1] earlier this week. As mentioned
there this version switches to a newer version of the RMM spec
(v1.0-rel0-rc1) which involves some (small) binary breaks to the
interface so you'll need to upgrade both host and guest kernel (and the
RMM) at the same time.

The focus has been on the guest side, so there's not much in the way of
big changes this time. The changes since v3[3] fit in three categories:

 1. Updates caused by the new RMM spec. In particular the 'num_bps' and
    'num_wps' fields now match the architectural ID_AA64DFR0_EL1
    register which avoids a number +1 and -1s in the code.

 2. A bunch of tidy ups handling the cases where kvm is NULL in various
    places.

 3. Misc changes due to rebasing (mostly caused by nested virt support).

Major limitations:

 * Only supports 4k host PAGE_SIZE (if PAGE_SIZE != 4k then the realm
   extensions are disabled).

 * No support for huge pages when mapping the guest's pages. There is
   some 'dead' code left over from before guest_mem was supported. This
   is partly a current limitation of guest_memfd.

The ABI to the RMM (the RMI) is based on RMM v1.0-rel0-rc1
specification[2].

This series is based on v6.11-rc1. It is also available as a git
repository:

https://gitlab.arm.com/linux-arm/linux-cca cca-host/v4

Work in progress changes for kvmtool are available from the git
repository below, these changes are based on Fuad Tabba's repository for
pKVM to provide some alignment with the ongoing pKVM work:

https://gitlab.arm.com/linux-arm/kvmtool-cca cca/v2

[1] https://lore.kernel.org/r/20240819131924.372366-1-steven.price%40arm.com
[2] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
[3] https://lore.kernel.org/r/20240610134202.54893-1-steven.price%40arm.com

Jean-Philippe Brucker (7):
  arm64: RME: Propagate number of breakpoints and watchpoints to
    userspace
  arm64: RME: Set breakpoint parameters through SET_ONE_REG
  arm64: RME: Initialize PMCR.N with number counter supported by RMM
  arm64: RME: Propagate max SVE vector length from RMM
  arm64: RME: Configure max SVE vector length for a Realm
  arm64: RME: Provide register list for unfinalized RME RECs
  arm64: RME: Provide accurate register list

Joey Gouly (2):
  arm64: rme: allow userspace to inject aborts
  arm64: rme: support RSI_HOST_CALL

Sean Christopherson (1):
  KVM: Prepare for handling only shared mappings in mmu_notifier events

Steven Price (29):
  arm64: RME: Handle Granule Protection Faults (GPFs)
  arm64: RME: Add SMC definitions for calling the RMM
  arm64: RME: Add wrappers for RMI calls
  arm64: RME: Check for RME support at KVM init
  arm64: RME: Define the user ABI
  arm64: RME: ioctls to create and configure realms
  arm64: kvm: Allow passing machine type in KVM creation
  arm64: RME: Keep a spare page delegated to the RMM
  arm64: RME: RTT tear down
  arm64: RME: Allocate/free RECs to match vCPUs
  arm64: RME: Support for the VGIC in realms
  KVM: arm64: Support timers in realm RECs
  arm64: RME: Allow VMM to set RIPAS
  arm64: RME: Handle realm enter/exit
  KVM: arm64: Handle realm MMIO emulation
  arm64: RME: Allow populating initial contents
  arm64: RME: Runtime faulting of memory
  KVM: arm64: Handle realm VCPU load
  KVM: arm64: Validate register access for a Realm VM
  KVM: arm64: Handle Realm PSCI requests
  KVM: arm64: WARN on injected undef exceptions
  arm64: Don't expose stolen time for realm guests
  arm64: RME: Always use 4k pages for realms
  arm64: rme: Prevent Device mappings for Realms
  arm_pmu: Provide a mechanism for disabling the physical IRQ
  arm64: rme: Enable PMU support with a realm guest
  kvm: rme: Hide KVM_CAP_READONLY_MEM for realm guests
  arm64: kvm: Expose support for private memory
  KVM: arm64: Allow activating realms

Suzuki K Poulose (4):
  kvm: arm64: pgtable: Track the number of pages in the entry level
  kvm: arm64: Include kvm_emulate.h in kvm/arm_psci.h
  kvm: arm64: Expose debug HW register numbers for Realm
  arm64: rme: Allow checking SVE on VM instance

 Documentation/virt/kvm/api.rst       |    3 +
 arch/arm64/include/asm/kvm_emulate.h |   34 +
 arch/arm64/include/asm/kvm_host.h    |   16 +-
 arch/arm64/include/asm/kvm_pgtable.h |    2 +
 arch/arm64/include/asm/kvm_rme.h     |  155 +++
 arch/arm64/include/asm/rmi_cmds.h    |  508 ++++++++
 arch/arm64/include/asm/rmi_smc.h     |  253 ++++
 arch/arm64/include/asm/virt.h        |    1 +
 arch/arm64/include/uapi/asm/kvm.h    |   49 +
 arch/arm64/kvm/Kconfig               |    1 +
 arch/arm64/kvm/Makefile              |    3 +-
 arch/arm64/kvm/arch_timer.c          |   45 +-
 arch/arm64/kvm/arm.c                 |  166 ++-
 arch/arm64/kvm/guest.c               |   99 +-
 arch/arm64/kvm/hyp/pgtable.c         |    5 +-
 arch/arm64/kvm/hypercalls.c          |    4 +-
 arch/arm64/kvm/inject_fault.c        |    2 +
 arch/arm64/kvm/mmio.c                |   10 +-
 arch/arm64/kvm/mmu.c                 |  181 ++-
 arch/arm64/kvm/pmu-emul.c            |    7 +-
 arch/arm64/kvm/psci.c                |   29 +
 arch/arm64/kvm/reset.c               |   23 +-
 arch/arm64/kvm/rme-exit.c            |  212 ++++
 arch/arm64/kvm/rme.c                 | 1620 ++++++++++++++++++++++++++
 arch/arm64/kvm/sys_regs.c            |   83 +-
 arch/arm64/kvm/vgic/vgic-v3.c        |    8 +-
 arch/arm64/kvm/vgic/vgic.c           |   37 +-
 arch/arm64/mm/fault.c                |   31 +-
 drivers/perf/arm_pmu.c               |   15 +
 include/kvm/arm_arch_timer.h         |    2 +
 include/kvm/arm_pmu.h                |    4 +
 include/kvm/arm_psci.h               |    2 +
 include/linux/kvm_host.h             |    2 +
 include/linux/perf/arm_pmu.h         |    5 +
 include/uapi/linux/kvm.h             |   31 +-
 virt/kvm/kvm_main.c                  |    7 +
 36 files changed, 3555 insertions(+), 100 deletions(-)
 create mode 100644 arch/arm64/include/asm/kvm_rme.h
 create mode 100644 arch/arm64/include/asm/rmi_cmds.h
 create mode 100644 arch/arm64/include/asm/rmi_smc.h
 create mode 100644 arch/arm64/kvm/rme-exit.c
 create mode 100644 arch/arm64/kvm/rme.c

-- 
2.34.1

[PATCH v4 01/43] KVM: Prepare for handling only shared mappings in mmu_notifier events

[Steven Price]

From: Sean Christopherson <seanjc@google.com>

Add flags to "struct kvm_gfn_range" to let notifier events target only
shared and only private mappings, and write up the existing mmu_notifier
events to be shared-only (private memory is never associated with a
userspace virtual address, i.e. can't be reached via mmu_notifiers).

Add two flags so that KVM can handle the three possibilities (shared,
private, and shared+private) without needing something like a tri-state
enum.

Link: https://lore.kernel.org/all/ZJX0hk+KpQP0KUyB@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 include/linux/kvm_host.h | 2 ++
 virt/kvm/kvm_main.c      | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 689e8be873a7..7393377c7656 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -265,6 +265,8 @@ struct kvm_gfn_range {
 	gfn_t start;
 	gfn_t end;
 	union kvm_mmu_notifier_arg arg;
+	bool only_private;
+	bool only_shared;
 	bool may_block;
 };
 bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index d0788d0a72cc..eaf16195b104 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -631,6 +631,13 @@ static __always_inline kvm_mn_ret_t __kvm_handle_hva_range(struct kvm *kvm,
 			 * the second or later invocation of the handler).
 			 */
 			gfn_range.arg = range->arg;
+
+			/*
+			 * HVA-based notifications aren't relevant to private
+			 * mappings as they don't have a userspace mapping.
+			 */
+			gfn_range.only_private = false;
+			gfn_range.only_shared = true;
 			gfn_range.may_block = range->may_block;
 
 			/*
-- 
2.34.1

[PATCH v4 02/43] kvm: arm64: pgtable: Track the number of pages in the entry level

[Steven Price]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

Keep track of the number of pages allocated for the top level PGD,
rather than computing it everytime (though we need it only twice now).
This will be used later by Arm CCA KVM changes.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 2 ++
 arch/arm64/kvm/hyp/pgtable.c         | 5 +++--
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 19278dfe7978..0350c08ada7a 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -362,6 +362,7 @@ static inline bool kvm_pgtable_walk_lock_held(void)
  * struct kvm_pgtable - KVM page-table.
  * @ia_bits:		Maximum input address size, in bits.
  * @start_level:	Level at which the page-table walk starts.
+ * @pgd_pages:		Number of pages in the entry level of the page-table.
  * @pgd:		Pointer to the first top-level entry of the page-table.
  * @mm_ops:		Memory management callbacks.
  * @mmu:		Stage-2 KVM MMU struct. Unused for stage-1 page-tables.
@@ -372,6 +373,7 @@ static inline bool kvm_pgtable_walk_lock_held(void)
 struct kvm_pgtable {
 	u32					ia_bits;
 	s8					start_level;
+	u8					pgd_pages;
 	kvm_pteref_t				pgd;
 	struct kvm_pgtable_mm_ops		*mm_ops;
 
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 9e2bbee77491..fb6675838b65 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1574,7 +1574,8 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
 	u32 sl0 = FIELD_GET(VTCR_EL2_SL0_MASK, vtcr);
 	s8 start_level = VTCR_EL2_TGRAN_SL0_BASE - sl0;
 
-	pgd_sz = kvm_pgd_pages(ia_bits, start_level) * PAGE_SIZE;
+	pgt->pgd_pages = kvm_pgd_pages(ia_bits, start_level);
+	pgd_sz = pgt->pgd_pages * PAGE_SIZE;
 	pgt->pgd = (kvm_pteref_t)mm_ops->zalloc_pages_exact(pgd_sz);
 	if (!pgt->pgd)
 		return -ENOMEM;
@@ -1626,7 +1627,7 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
 	};
 
 	WARN_ON(kvm_pgtable_walk(pgt, 0, BIT(pgt->ia_bits), &walker));
-	pgd_sz = kvm_pgd_pages(pgt->ia_bits, pgt->start_level) * PAGE_SIZE;
+	pgd_sz = pgt->pgd_pages * PAGE_SIZE;
 	pgt->mm_ops->free_pages_exact(kvm_dereference_pteref(&walker, pgt->pgd), pgd_sz);
 	pgt->pgd = NULL;
 }
-- 
2.34.1

[PATCH v4 03/43] kvm: arm64: Include kvm_emulate.h in kvm/arm_psci.h

[Steven Price]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

Fix a potential build error (like below, when asm/kvm_emulate.h gets
included after the kvm/arm_psci.h) by including the missing header file
in kvm/arm_psci.h:

./include/kvm/arm_psci.h: In function ‘kvm_psci_version’:
./include/kvm/arm_psci.h:29:13: error: implicit declaration of function
   ‘vcpu_has_feature’; did you mean ‘cpu_have_feature’? [-Werror=implicit-function-declaration]
   29 |         if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_PSCI_0_2)) {
	         |             ^~~~~~~~~~~~~~~~
			       |             cpu_have_feature

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 include/kvm/arm_psci.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/kvm/arm_psci.h b/include/kvm/arm_psci.h
index e8fb624013d1..1801c6fd3f10 100644
--- a/include/kvm/arm_psci.h
+++ b/include/kvm/arm_psci.h
@@ -10,6 +10,8 @@
 #include <linux/kvm_host.h>
 #include <uapi/linux/psci.h>
 
+#include <asm/kvm_emulate.h>
+
 #define KVM_ARM_PSCI_0_1	PSCI_VERSION(0, 1)
 #define KVM_ARM_PSCI_0_2	PSCI_VERSION(0, 2)
 #define KVM_ARM_PSCI_1_0	PSCI_VERSION(1, 0)
-- 
2.34.1

[PATCH v4 04/43] arm64: RME: Handle Granule Protection Faults (GPFs)

[Steven Price]

If the host attempts to access granules that have been delegated for use
in a realm these accesses will be caught and will trigger a Granule
Protection Fault (GPF).

A fault during a page walk signals a bug in the kernel and is handled by
oopsing the kernel. A non-page walk fault could be caused by user space
having access to a page which has been delegated to the kernel and will
trigger a SIGBUS to allow debugging why user space is trying to access a
delegated page.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Include missing "Granule Protection Fault at level -1"
---
 arch/arm64/mm/fault.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 451ba7cbd5ad..8adc0d0b41a2 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -751,6 +751,25 @@ static int do_tag_check_fault(unsigned long far, unsigned long esr,
 	return 0;
 }
 
+static int do_gpf_ptw(unsigned long far, unsigned long esr, struct pt_regs *regs)
+{
+	const struct fault_info *inf = esr_to_fault_info(esr);
+
+	die_kernel_fault(inf->name, far, esr, regs);
+	return 0;
+}
+
+static int do_gpf(unsigned long far, unsigned long esr, struct pt_regs *regs)
+{
+	const struct fault_info *inf = esr_to_fault_info(esr);
+
+	if (!is_el1_instruction_abort(esr) && fixup_exception(regs))
+		return 0;
+
+	arm64_notify_die(inf->name, regs, inf->sig, inf->code, far, esr);
+	return 0;
+}
+
 static const struct fault_info fault_info[] = {
 	{ do_bad,		SIGKILL, SI_KERNEL,	"ttbr address size fault"	},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"level 1 address size fault"	},
@@ -787,12 +806,12 @@ static const struct fault_info fault_info[] = {
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 32"			},
 	{ do_alignment_fault,	SIGBUS,  BUS_ADRALN,	"alignment fault"		},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 34"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 35"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 36"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 37"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 38"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 39"			},
-	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 40"			},
+	{ do_gpf_ptw,		SIGKILL, SI_KERNEL,	"Granule Protection Fault at level -1" },
+	{ do_gpf_ptw,		SIGKILL, SI_KERNEL,	"Granule Protection Fault at level 0" },
+	{ do_gpf_ptw,		SIGKILL, SI_KERNEL,	"Granule Protection Fault at level 1" },
+	{ do_gpf_ptw,		SIGKILL, SI_KERNEL,	"Granule Protection Fault at level 2" },
+	{ do_gpf_ptw,		SIGKILL, SI_KERNEL,	"Granule Protection Fault at level 3" },
+	{ do_gpf,		SIGBUS,  SI_KERNEL,	"Granule Protection Fault not on table walk" },
 	{ do_bad,		SIGKILL, SI_KERNEL,	"level -1 address size fault"	},
 	{ do_bad,		SIGKILL, SI_KERNEL,	"unknown 42"			},
 	{ do_translation_fault,	SIGSEGV, SEGV_MAPERR,	"level -1 translation fault"	},
-- 
2.34.1

[PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the RMM

[Steven Price]

The RMM (Realm Management Monitor) provides functionality that can be
accessed by SMC calls from the host.

The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1

[1] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v3:
 * Update to match RMM spec v1.0-rel0-rc1.
Changes since v2:
 * Fix specification link.
 * Rename rec_entry->rec_enter to match spec.
 * Fix size of pmu_ovf_status to match spec.
---
 arch/arm64/include/asm/rmi_smc.h | 253 +++++++++++++++++++++++++++++++
 1 file changed, 253 insertions(+)
 create mode 100644 arch/arm64/include/asm/rmi_smc.h

diff --git a/arch/arm64/include/asm/rmi_smc.h b/arch/arm64/include/asm/rmi_smc.h
new file mode 100644
index 000000000000..5ee71c12a9cd
--- /dev/null
+++ b/arch/arm64/include/asm/rmi_smc.h
@@ -0,0 +1,253 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023-2024 ARM Ltd.
+ *
+ * The values and structures in this file are from the Realm Management Monitor
+ * specification (DEN0137) version 1.0-rel0-rc1:
+ * https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
+ */
+
+#ifndef __ASM_RME_SMC_H
+#define __ASM_RME_SMC_H
+
+#include <linux/arm-smccc.h>
+
+#define SMC_RxI_CALL(func)				\
+	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
+			   ARM_SMCCC_SMC_64,		\
+			   ARM_SMCCC_OWNER_STANDARD,	\
+			   (func))
+
+#define SMC_RMI_DATA_CREATE		SMC_RxI_CALL(0x0153)
+#define SMC_RMI_DATA_CREATE_UNKNOWN	SMC_RxI_CALL(0x0154)
+#define SMC_RMI_DATA_DESTROY		SMC_RxI_CALL(0x0155)
+#define SMC_RMI_FEATURES		SMC_RxI_CALL(0x0165)
+#define SMC_RMI_GRANULE_DELEGATE	SMC_RxI_CALL(0x0151)
+#define SMC_RMI_GRANULE_UNDELEGATE	SMC_RxI_CALL(0x0152)
+#define SMC_RMI_PSCI_COMPLETE		SMC_RxI_CALL(0x0164)
+#define SMC_RMI_REALM_ACTIVATE		SMC_RxI_CALL(0x0157)
+#define SMC_RMI_REALM_CREATE		SMC_RxI_CALL(0x0158)
+#define SMC_RMI_REALM_DESTROY		SMC_RxI_CALL(0x0159)
+#define SMC_RMI_REC_AUX_COUNT		SMC_RxI_CALL(0x0167)
+#define SMC_RMI_REC_CREATE		SMC_RxI_CALL(0x015a)
+#define SMC_RMI_REC_DESTROY		SMC_RxI_CALL(0x015b)
+#define SMC_RMI_REC_ENTER		SMC_RxI_CALL(0x015c)
+#define SMC_RMI_RTT_CREATE		SMC_RxI_CALL(0x015d)
+#define SMC_RMI_RTT_DESTROY		SMC_RxI_CALL(0x015e)
+#define SMC_RMI_RTT_FOLD		SMC_RxI_CALL(0x0166)
+#define SMC_RMI_RTT_INIT_RIPAS		SMC_RxI_CALL(0x0168)
+#define SMC_RMI_RTT_MAP_UNPROTECTED	SMC_RxI_CALL(0x015f)
+#define SMC_RMI_RTT_READ_ENTRY		SMC_RxI_CALL(0x0161)
+#define SMC_RMI_RTT_SET_RIPAS		SMC_RxI_CALL(0x0169)
+#define SMC_RMI_RTT_UNMAP_UNPROTECTED	SMC_RxI_CALL(0x0162)
+#define SMC_RMI_VERSION			SMC_RxI_CALL(0x0150)
+
+#define RMI_ABI_MAJOR_VERSION	1
+#define RMI_ABI_MINOR_VERSION	0
+
+#define RMI_UNASSIGNED			0
+#define RMI_ASSIGNED			1
+#define RMI_TABLE			2
+
+#define RMI_ABI_VERSION_GET_MAJOR(version) ((version) >> 16)
+#define RMI_ABI_VERSION_GET_MINOR(version) ((version) & 0xFFFF)
+#define RMI_ABI_VERSION(major, minor)      (((major) << 16) | (minor))
+
+#define RMI_RETURN_STATUS(ret)		((ret) & 0xFF)
+#define RMI_RETURN_INDEX(ret)		(((ret) >> 8) & 0xFF)
+
+#define RMI_SUCCESS		0
+#define RMI_ERROR_INPUT		1
+#define RMI_ERROR_REALM		2
+#define RMI_ERROR_REC		3
+#define RMI_ERROR_RTT		4
+
+#define RMI_EMPTY		0
+#define RMI_RAM			1
+#define RMI_DESTROYED		2
+
+#define RMI_NO_MEASURE_CONTENT	0
+#define RMI_MEASURE_CONTENT	1
+
+#define RMI_FEATURE_REGISTER_0_S2SZ		GENMASK(7, 0)
+#define RMI_FEATURE_REGISTER_0_LPA2		BIT(8)
+#define RMI_FEATURE_REGISTER_0_SVE_EN		BIT(9)
+#define RMI_FEATURE_REGISTER_0_SVE_VL		GENMASK(13, 10)
+#define RMI_FEATURE_REGISTER_0_NUM_BPS		GENMASK(19, 14)
+#define RMI_FEATURE_REGISTER_0_NUM_WPS		GENMASK(25, 20)
+#define RMI_FEATURE_REGISTER_0_PMU_EN		BIT(26)
+#define RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS	GENMASK(31, 27)
+#define RMI_FEATURE_REGISTER_0_HASH_SHA_256	BIT(32)
+#define RMI_FEATURE_REGISTER_0_HASH_SHA_512	BIT(33)
+#define RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS	GENMASK(37, 34)
+#define RMI_FEATURE_REGISTER_0_MAX_RECS_ORDER	GENMASK(41, 38)
+
+#define RMI_REALM_PARAM_FLAG_LPA2		BIT(0)
+#define RMI_REALM_PARAM_FLAG_SVE		BIT(1)
+#define RMI_REALM_PARAM_FLAG_PMU		BIT(2)
+
+/*
+ * Note many of these fields are smaller than u64 but all fields have u64
+ * alignment, so use u64 to ensure correct alignment.
+ */
+struct realm_params {
+	union { /* 0x0 */
+		struct {
+			u64 flags;
+			u64 s2sz;
+			u64 sve_vl;
+			u64 num_bps;
+			u64 num_wps;
+			u64 pmu_num_ctrs;
+			u64 hash_algo;
+		};
+		u8 padding_1[0x400];
+	};
+	union { /* 0x400 */
+		u8 rpv[64];
+		u8 padding_2[0x400];
+	};
+	union { /* 0x800 */
+		struct {
+			u64 vmid;
+			u64 rtt_base;
+			s64 rtt_level_start;
+			u64 rtt_num_start;
+		};
+		u8 padding_3[0x800];
+	};
+};
+
+/*
+ * The number of GPRs (starting from X0) that are
+ * configured by the host when a REC is created.
+ */
+#define REC_CREATE_NR_GPRS		8
+
+#define REC_PARAMS_FLAG_RUNNABLE	BIT_ULL(0)
+
+#define REC_PARAMS_AUX_GRANULES		16
+
+struct rec_params {
+	union { /* 0x0 */
+		u64 flags;
+		u8 padding1[0x100];
+	};
+	union { /* 0x100 */
+		u64 mpidr;
+		u8 padding2[0x100];
+	};
+	union { /* 0x200 */
+		u64 pc;
+		u8 padding3[0x100];
+	};
+	union { /* 0x300 */
+		u64 gprs[REC_CREATE_NR_GPRS];
+		u8 padding4[0x500];
+	};
+	union { /* 0x800 */
+		struct {
+			u64 num_rec_aux;
+			u64 aux[REC_PARAMS_AUX_GRANULES];
+		};
+		u8 padding5[0x800];
+	};
+};
+
+#define RMI_EMULATED_MMIO		BIT(0)
+#define RMI_INJECT_SEA			BIT(1)
+#define RMI_TRAP_WFI			BIT(2)
+#define RMI_TRAP_WFE			BIT(3)
+#define RMI_RIPAS_RESPONSE		BIT(4)
+
+#define REC_RUN_GPRS			31
+#define REC_GIC_NUM_LRS			16
+
+struct rec_enter {
+	union { /* 0x000 */
+		u64 flags;
+		u8 padding0[0x200];
+	};
+	union { /* 0x200 */
+		u64 gprs[REC_RUN_GPRS];
+		u8 padding2[0x100];
+	};
+	union { /* 0x300 */
+		struct {
+			u64 gicv3_hcr;
+			u64 gicv3_lrs[REC_GIC_NUM_LRS];
+		};
+		u8 padding3[0x100];
+	};
+	u8 padding4[0x400];
+};
+
+#define RMI_EXIT_SYNC			0x00
+#define RMI_EXIT_IRQ			0x01
+#define RMI_EXIT_FIQ			0x02
+#define RMI_EXIT_PSCI			0x03
+#define RMI_EXIT_RIPAS_CHANGE		0x04
+#define RMI_EXIT_HOST_CALL		0x05
+#define RMI_EXIT_SERROR			0x06
+
+struct rec_exit {
+	union { /* 0x000 */
+		u8 exit_reason;
+		u8 padding0[0x100];
+	};
+	union { /* 0x100 */
+		struct {
+			u64 esr;
+			u64 far;
+			u64 hpfar;
+		};
+		u8 padding1[0x100];
+	};
+	union { /* 0x200 */
+		u64 gprs[REC_RUN_GPRS];
+		u8 padding2[0x100];
+	};
+	union { /* 0x300 */
+		struct {
+			u64 gicv3_hcr;
+			u64 gicv3_lrs[REC_GIC_NUM_LRS];
+			u64 gicv3_misr;
+			u64 gicv3_vmcr;
+		};
+		u8 padding3[0x100];
+	};
+	union { /* 0x400 */
+		struct {
+			u64 cntp_ctl;
+			u64 cntp_cval;
+			u64 cntv_ctl;
+			u64 cntv_cval;
+		};
+		u8 padding4[0x100];
+	};
+	union { /* 0x500 */
+		struct {
+			u64 ripas_base;
+			u64 ripas_top;
+			u64 ripas_value;
+		};
+		u8 padding5[0x100];
+	};
+	union { /* 0x600 */
+		u16 imm;
+		u8 padding6[0x100];
+	};
+	union { /* 0x700 */
+		struct {
+			u8 pmu_ovf_status;
+		};
+		u8 padding7[0x100];
+	};
+};
+
+struct rec_run {
+	struct rec_enter enter;
+	struct rec_exit exit;
+};
+
+#endif
-- 
2.34.1

Re: [PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the RMM

[Suzuki K Poulose]

Hi Steven

On 21/08/2024 16:38, Steven Price wrote:
> The RMM (Realm Management Monitor) provides functionality that can be
> accessed by SMC calls from the host.
> 
> The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1
> 
> [1] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
> 

The definitions match RMM spec. Some ultra minor comments below, feel 
free to ignore ;-)

> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v3:
>   * Update to match RMM spec v1.0-rel0-rc1.
> Changes since v2:
>   * Fix specification link.
>   * Rename rec_entry->rec_enter to match spec.
>   * Fix size of pmu_ovf_status to match spec.
> ---
>   arch/arm64/include/asm/rmi_smc.h | 253 +++++++++++++++++++++++++++++++
>   1 file changed, 253 insertions(+)
>   create mode 100644 arch/arm64/include/asm/rmi_smc.h
> 
> diff --git a/arch/arm64/include/asm/rmi_smc.h b/arch/arm64/include/asm/rmi_smc.h
> new file mode 100644
> index 000000000000..5ee71c12a9cd
> --- /dev/null
> +++ b/arch/arm64/include/asm/rmi_smc.h
> @@ -0,0 +1,253 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2023-2024 ARM Ltd.
> + *
> + * The values and structures in this file are from the Realm Management Monitor
> + * specification (DEN0137) version 1.0-rel0-rc1:
> + * https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
> + */
> +
> +#ifndef __ASM_RME_SMC_H
> +#define __ASM_RME_SMC_H
> +
> +#include <linux/arm-smccc.h>
> +
> +#define SMC_RxI_CALL(func)				\
> +	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,		\
> +			   ARM_SMCCC_SMC_64,		\
> +			   ARM_SMCCC_OWNER_STANDARD,	\
> +			   (func))
> +
> +#define SMC_RMI_DATA_CREATE		SMC_RxI_CALL(0x0153)
> +#define SMC_RMI_DATA_CREATE_UNKNOWN	SMC_RxI_CALL(0x0154)
> +#define SMC_RMI_DATA_DESTROY		SMC_RxI_CALL(0x0155)
> +#define SMC_RMI_FEATURES		SMC_RxI_CALL(0x0165)
> +#define SMC_RMI_GRANULE_DELEGATE	SMC_RxI_CALL(0x0151)
> +#define SMC_RMI_GRANULE_UNDELEGATE	SMC_RxI_CALL(0x0152)
> +#define SMC_RMI_PSCI_COMPLETE		SMC_RxI_CALL(0x0164)
> +#define SMC_RMI_REALM_ACTIVATE		SMC_RxI_CALL(0x0157)
> +#define SMC_RMI_REALM_CREATE		SMC_RxI_CALL(0x0158)
> +#define SMC_RMI_REALM_DESTROY		SMC_RxI_CALL(0x0159)
> +#define SMC_RMI_REC_AUX_COUNT		SMC_RxI_CALL(0x0167)
> +#define SMC_RMI_REC_CREATE		SMC_RxI_CALL(0x015a)
> +#define SMC_RMI_REC_DESTROY		SMC_RxI_CALL(0x015b)
> +#define SMC_RMI_REC_ENTER		SMC_RxI_CALL(0x015c)
> +#define SMC_RMI_RTT_CREATE		SMC_RxI_CALL(0x015d)
> +#define SMC_RMI_RTT_DESTROY		SMC_RxI_CALL(0x015e)
> +#define SMC_RMI_RTT_FOLD		SMC_RxI_CALL(0x0166)
> +#define SMC_RMI_RTT_INIT_RIPAS		SMC_RxI_CALL(0x0168)
> +#define SMC_RMI_RTT_MAP_UNPROTECTED	SMC_RxI_CALL(0x015f)
> +#define SMC_RMI_RTT_READ_ENTRY		SMC_RxI_CALL(0x0161)
> +#define SMC_RMI_RTT_SET_RIPAS		SMC_RxI_CALL(0x0169)
> +#define SMC_RMI_RTT_UNMAP_UNPROTECTED	SMC_RxI_CALL(0x0162)
> +#define SMC_RMI_VERSION			SMC_RxI_CALL(0x0150)
> +
> +#define RMI_ABI_MAJOR_VERSION	1
> +#define RMI_ABI_MINOR_VERSION	0
> +
> +#define RMI_UNASSIGNED			0
> +#define RMI_ASSIGNED			1
> +#define RMI_TABLE			2
> +
> +#define RMI_ABI_VERSION_GET_MAJOR(version) ((version) >> 16)
> +#define RMI_ABI_VERSION_GET_MINOR(version) ((version) & 0xFFFF)
> +#define RMI_ABI_VERSION(major, minor)      (((major) << 16) | (minor))

super minor nit: Please could we keep it closer to the 
RMI_ABI_M..R_VERSION defintions ?
	
> +
> +#define RMI_RETURN_STATUS(ret)		((ret) & 0xFF)
> +#define RMI_RETURN_INDEX(ret)		(((ret) >> 8) & 0xFF)
> +
> +#define RMI_SUCCESS		0
> +#define RMI_ERROR_INPUT		1
> +#define RMI_ERROR_REALM		2
> +#define RMI_ERROR_REC		3
> +#define RMI_ERROR_RTT		4
> +
> +#define RMI_EMPTY		0
> +#define RMI_RAM			1
> +#define RMI_DESTROYED		2
> +
> +#define RMI_NO_MEASURE_CONTENT	0
> +#define RMI_MEASURE_CONTENT	1
> +
> +#define RMI_FEATURE_REGISTER_0_S2SZ		GENMASK(7, 0)
> +#define RMI_FEATURE_REGISTER_0_LPA2		BIT(8)
> +#define RMI_FEATURE_REGISTER_0_SVE_EN		BIT(9)
> +#define RMI_FEATURE_REGISTER_0_SVE_VL		GENMASK(13, 10)
> +#define RMI_FEATURE_REGISTER_0_NUM_BPS		GENMASK(19, 14)
> +#define RMI_FEATURE_REGISTER_0_NUM_WPS		GENMASK(25, 20)
> +#define RMI_FEATURE_REGISTER_0_PMU_EN		BIT(26)
> +#define RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS	GENMASK(31, 27)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_256	BIT(32)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_512	BIT(33)
> +#define RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS	GENMASK(37, 34)
> +#define RMI_FEATURE_REGISTER_0_MAX_RECS_ORDER	GENMASK(41, 38)
> +
> +#define RMI_REALM_PARAM_FLAG_LPA2		BIT(0)
> +#define RMI_REALM_PARAM_FLAG_SVE		BIT(1)
> +#define RMI_REALM_PARAM_FLAG_PMU		BIT(2)
> +
> +/*
> + * Note many of these fields are smaller than u64 but all fields have u64
> + * alignment, so use u64 to ensure correct alignment.
> + */
> +struct realm_params {
> +	union { /* 0x0 */
> +		struct {
> +			u64 flags;
> +			u64 s2sz;
> +			u64 sve_vl;
> +			u64 num_bps;
> +			u64 num_wps;
> +			u64 pmu_num_ctrs;
> +			u64 hash_algo;
> +		};
> +		u8 padding_1[0x400];

super minor nit: padding_[0-9] vs padding[0-9] below for other objects.
It may be nicer to keep them consistent.

> +	};
> +	union { /* 0x400 */
> +		u8 rpv[64];
> +		u8 padding_2[0x400];
> +	};
> +	union { /* 0x800 */
> +		struct {
> +			u64 vmid;
> +			u64 rtt_base;
> +			s64 rtt_level_start;
> +			u64 rtt_num_start;
> +		};
> +		u8 padding_3[0x800];
> +	};
> +};
> +
> +/*
> + * The number of GPRs (starting from X0) that are
> + * configured by the host when a REC is created.
> + */
> +#define REC_CREATE_NR_GPRS		8
> +
> +#define REC_PARAMS_FLAG_RUNNABLE	BIT_ULL(0)
> +
> +#define REC_PARAMS_AUX_GRANULES		16
> +
> +struct rec_params {
> +	union { /* 0x0 */
> +		u64 flags;
> +		u8 padding1[0x100];
> +	};
> +	union { /* 0x100 */
> +		u64 mpidr;
> +		u8 padding2[0x100];
> +	};
> +	union { /* 0x200 */
> +		u64 pc;
> +		u8 padding3[0x100];
> +	};
> +	union { /* 0x300 */
> +		u64 gprs[REC_CREATE_NR_GPRS];
> +		u8 padding4[0x500];
> +	};
> +	union { /* 0x800 */
> +		struct {
> +			u64 num_rec_aux;
> +			u64 aux[REC_PARAMS_AUX_GRANULES];
> +		};
> +		u8 padding5[0x800];
> +	};
> +};
> +
> +#define RMI_EMULATED_MMIO		BIT(0)
> +#define RMI_INJECT_SEA			BIT(1)
> +#define RMI_TRAP_WFI			BIT(2)
> +#define RMI_TRAP_WFE			BIT(3)
> +#define RMI_RIPAS_RESPONSE		BIT(4)

minor nit: I was hoping to suggest something that gives a clue of
REC_ENTER_FLAGS, but it may be too long.

#define RMI_REC_ENTER_FLAG_EMULATED_MMIO	BIT(0)
#define RMI_REC_ENTER_..

similar to REC_PARAM_FLAG/RMI_PARAM_FLAG.

May be REC_ENTER_FLAG_xxx even. Thoughts ?

Suzuki

> +
> +#define REC_RUN_GPRS			31
> +#define REC_GIC_NUM_LRS			16
> +
> +struct rec_enter {
> +	union { /* 0x000 */
> +		u64 flags;
> +		u8 padding0[0x200];
> +	};
> +	union { /* 0x200 */
> +		u64 gprs[REC_RUN_GPRS];
> +		u8 padding2[0x100];
> +	};
> +	union { /* 0x300 */
> +		struct {
> +			u64 gicv3_hcr;
> +			u64 gicv3_lrs[REC_GIC_NUM_LRS];
> +		};
> +		u8 padding3[0x100];
> +	};
> +	u8 padding4[0x400];
> +};
> +
> +#define RMI_EXIT_SYNC			0x00
> +#define RMI_EXIT_IRQ			0x01
> +#define RMI_EXIT_FIQ			0x02
> +#define RMI_EXIT_PSCI			0x03
> +#define RMI_EXIT_RIPAS_CHANGE		0x04
> +#define RMI_EXIT_HOST_CALL		0x05
> +#define RMI_EXIT_SERROR			0x06
> +
> +struct rec_exit {
> +	union { /* 0x000 */
> +		u8 exit_reason;
> +		u8 padding0[0x100];
> +	};
> +	union { /* 0x100 */
> +		struct {
> +			u64 esr;
> +			u64 far;
> +			u64 hpfar;
> +		};
> +		u8 padding1[0x100];
> +	};
> +	union { /* 0x200 */
> +		u64 gprs[REC_RUN_GPRS];
> +		u8 padding2[0x100];
> +	};
> +	union { /* 0x300 */
> +		struct {
> +			u64 gicv3_hcr;
> +			u64 gicv3_lrs[REC_GIC_NUM_LRS];
> +			u64 gicv3_misr;
> +			u64 gicv3_vmcr;
> +		};
> +		u8 padding3[0x100];
> +	};
> +	union { /* 0x400 */
> +		struct {
> +			u64 cntp_ctl;
> +			u64 cntp_cval;
> +			u64 cntv_ctl;
> +			u64 cntv_cval;
> +		};
> +		u8 padding4[0x100];
> +	};
> +	union { /* 0x500 */
> +		struct {
> +			u64 ripas_base;
> +			u64 ripas_top;
> +			u64 ripas_value;
> +		};
> +		u8 padding5[0x100];
> +	};
> +	union { /* 0x600 */
> +		u16 imm;
> +		u8 padding6[0x100];
> +	};
> +	union { /* 0x700 */
> +		struct {
> +			u8 pmu_ovf_status;
> +		};
> +		u8 padding7[0x100];
> +	};
> +};
> +
> +struct rec_run {
> +	struct rec_enter enter;
> +	struct rec_exit exit;
> +};
> +
> +#endif

Re: [PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the RMM

[Gavin Shan]

Hi Steven,

On 8/22/24 1:38 AM, Steven Price wrote:
> The RMM (Realm Management Monitor) provides functionality that can be
> accessed by SMC calls from the host.
> 
> The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1
> 
> [1] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
> 
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v3:
>   * Update to match RMM spec v1.0-rel0-rc1.
> Changes since v2:
>   * Fix specification link.
>   * Rename rec_entry->rec_enter to match spec.
>   * Fix size of pmu_ovf_status to match spec.
> ---
>   arch/arm64/include/asm/rmi_smc.h | 253 +++++++++++++++++++++++++++++++
>   1 file changed, 253 insertions(+)
>   create mode 100644 arch/arm64/include/asm/rmi_smc.h
> 

[...]

> +
> +#define RMI_FEATURE_REGISTER_0_S2SZ		GENMASK(7, 0)
> +#define RMI_FEATURE_REGISTER_0_LPA2		BIT(8)
> +#define RMI_FEATURE_REGISTER_0_SVE_EN		BIT(9)
> +#define RMI_FEATURE_REGISTER_0_SVE_VL		GENMASK(13, 10)
> +#define RMI_FEATURE_REGISTER_0_NUM_BPS		GENMASK(19, 14)
> +#define RMI_FEATURE_REGISTER_0_NUM_WPS		GENMASK(25, 20)
> +#define RMI_FEATURE_REGISTER_0_PMU_EN		BIT(26)
> +#define RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS	GENMASK(31, 27)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_256	BIT(32)
> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_512	BIT(33)
> +#define RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS	GENMASK(37, 34)
> +#define RMI_FEATURE_REGISTER_0_MAX_RECS_ORDER	GENMASK(41, 38)
> +

Those definitions aren't consistent to tf-rmm at least. For example, the latest tf-rmm
has bit-28 and bit-29 for RMI_FEATURE_REGISTER_0_HASH_SHA_{256, 512}. I didn't check the
specification yet, but they need to be corrected in Linux host or tf-rmm.

   git@github.com:TF-RMM/tf-rmm.git
   head: 258b7952640b Merge "fix(tools/clang-tidy): ignore header include check" into integration

   [gshan@gshan tf-rmm]$ git grep RMI_FEATURE_REGISTER_0_HASH_SHA.*_SHIFT
   lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_256_SHIFT     UL(28)
   lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_512_SHIFT     UL(29)

Due to the inconsistent definitions, I'm unable to start a guest with the following
combination: linux-host/cca-host/v4, linux-guest/cca-guest/v5, kvmtool/cca/v2.

   # ./start_guest.sh
   Info: # lkvm run -k Image -m 256 -c 2 --name guest-152
   [  145.894085] config_realm_hash_algo: unsupported ALGO_SHA256 by rmm_feat_reg0=0x0000000034488e30
   KVM_CAP_RME(KVM_CAP_ARM_RME_CONFIG_REALM) hash_algo: Invalid argument

Thanks,
Gavin

Re: [PATCH v4 05/43] arm64: RME: Add SMC definitions for calling the RMM

[Gavin Shan]

On 9/6/24 10:11 AM, Gavin Shan wrote:
> On 8/22/24 1:38 AM, Steven Price wrote:
>> The RMM (Realm Management Monitor) provides functionality that can be
>> accessed by SMC calls from the host.
>>
>> The SMC definitions are based on DEN0137[1] version 1.0-rel0-rc1
>>
>> [1] https://developer.arm.com/-/cdn-downloads/permalink/PDF/Architectures/DEN0137_1.0-rel0-rc1_rmm-arch_external.pdf
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v3:
>>   * Update to match RMM spec v1.0-rel0-rc1.
>> Changes since v2:
>>   * Fix specification link.
>>   * Rename rec_entry->rec_enter to match spec.
>>   * Fix size of pmu_ovf_status to match spec.
>> ---
>>   arch/arm64/include/asm/rmi_smc.h | 253 +++++++++++++++++++++++++++++++
>>   1 file changed, 253 insertions(+)
>>   create mode 100644 arch/arm64/include/asm/rmi_smc.h
>>
> 
> [...]
> 
>> +
>> +#define RMI_FEATURE_REGISTER_0_S2SZ        GENMASK(7, 0)
>> +#define RMI_FEATURE_REGISTER_0_LPA2        BIT(8)
>> +#define RMI_FEATURE_REGISTER_0_SVE_EN        BIT(9)
>> +#define RMI_FEATURE_REGISTER_0_SVE_VL        GENMASK(13, 10)
>> +#define RMI_FEATURE_REGISTER_0_NUM_BPS        GENMASK(19, 14)
>> +#define RMI_FEATURE_REGISTER_0_NUM_WPS        GENMASK(25, 20)
>> +#define RMI_FEATURE_REGISTER_0_PMU_EN        BIT(26)
>> +#define RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS    GENMASK(31, 27)
>> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_256    BIT(32)
>> +#define RMI_FEATURE_REGISTER_0_HASH_SHA_512    BIT(33)
>> +#define RMI_FEATURE_REGISTER_0_GICV3_NUM_LRS    GENMASK(37, 34)
>> +#define RMI_FEATURE_REGISTER_0_MAX_RECS_ORDER    GENMASK(41, 38)
>> +
> 
> Those definitions aren't consistent to tf-rmm at least. For example, the latest tf-rmm
> has bit-28 and bit-29 for RMI_FEATURE_REGISTER_0_HASH_SHA_{256, 512}. I didn't check the
> specification yet, but they need to be corrected in Linux host or tf-rmm.
> 
>    git@github.com:TF-RMM/tf-rmm.git
>    head: 258b7952640b Merge "fix(tools/clang-tidy): ignore header include check" into integration
> 
>    [gshan@gshan tf-rmm]$ git grep RMI_FEATURE_REGISTER_0_HASH_SHA.*_SHIFT
>    lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_256_SHIFT     UL(28)
>    lib/smc/include/smc-rmi.h:#define RMI_FEATURE_REGISTER_0_HASH_SHA_512_SHIFT     UL(29)
> 
> Due to the inconsistent definitions, I'm unable to start a guest with the following
> combination: linux-host/cca-host/v4, linux-guest/cca-guest/v5, kvmtool/cca/v2.
> 
>    # ./start_guest.sh
>    Info: # lkvm run -k Image -m 256 -c 2 --name guest-152
>    [  145.894085] config_realm_hash_algo: unsupported ALGO_SHA256 by rmm_feat_reg0=0x0000000034488e30
>    KVM_CAP_RME(KVM_CAP_ARM_RME_CONFIG_REALM) hash_algo: Invalid argument
> 

Please ignore above comments. As Steven pointed out in another thread, the TF-RMM needs to
be something other than the latest upstream one. With the TF-RMM, I'm able to boot the guest
with cca/host-v4 and cca/guest-v5.

   git fetch https://git.trustedfirmware.org/TF-RMM/tf-rmm.git \
   refs/changes/85/30485/11

Thanks,
Gavin

[PATCH v4 06/43] arm64: RME: Add wrappers for RMI calls

[Steven Price]

The wrappers make the call sites easier to read and deal with the
boiler plate of handling the error codes from the RMM.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes from v2:
 * Make output arguments optional.
 * Mask RIPAS value rmi_rtt_read_entry()
 * Drop unused rmi_rtt_get_phys()
---
 arch/arm64/include/asm/rmi_cmds.h | 508 ++++++++++++++++++++++++++++++
 1 file changed, 508 insertions(+)
 create mode 100644 arch/arm64/include/asm/rmi_cmds.h

diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/asm/rmi_cmds.h
new file mode 100644
index 000000000000..5288fed4c11a
--- /dev/null
+++ b/arch/arm64/include/asm/rmi_cmds.h
@@ -0,0 +1,508 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_RMI_CMDS_H
+#define __ASM_RMI_CMDS_H
+
+#include <linux/arm-smccc.h>
+
+#include <asm/rmi_smc.h>
+
+struct rtt_entry {
+	unsigned long walk_level;
+	unsigned long desc;
+	int state;
+	int ripas;
+};
+
+/**
+ * rmi_data_create() - Create a Data Granule
+ * @rd: PA of the RD
+ * @data: PA of the target granule
+ * @ipa: IPA at which the granule will be mapped in the guest
+ * @src: PA of the source granule
+ * @flags: RMI_MEASURE_CONTENT if the contents should be measured
+ *
+ * Create a new Data Granule, copying contents from a Non-secure Granule.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_data_create(unsigned long rd, unsigned long data,
+				  unsigned long ipa, unsigned long src,
+				  unsigned long flags)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_DATA_CREATE, rd, data, ipa, src,
+			     flags, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_data_create_unknown() - Create a Data Granule with unknown contents
+ * @rd: PA of the RD
+ * @data: PA of the target granule
+ * @ipa: IPA at which the granule will be mapped in the guest
+ *
+ * Create a new Data Granule with unknown contents
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_data_create_unknown(unsigned long rd,
+					  unsigned long data,
+					  unsigned long ipa)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_DATA_CREATE_UNKNOWN, rd, data, ipa, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_data_destroy() - Destroy a Data Granule
+ * @rd: PA of the RD
+ * @ipa: IPA at which the granule is mapped in the guest
+ * @data_out: PA of the granule which was destroyed
+ * @top_out: Top IPA of non-live RTT entries
+ *
+ * Transitions the granule to DESTROYED state, the address cannot be used by
+ * the guest for the lifetime of the Realm.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_data_destroy(unsigned long rd, unsigned long ipa,
+				   unsigned long *data_out,
+				   unsigned long *top_out)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_DATA_DESTROY, rd, ipa, &res);
+
+	if (data_out)
+		*data_out = res.a1;
+	if (top_out)
+		*top_out = res.a2;
+
+	return res.a0;
+}
+
+/**
+ * rmi_features() - Read feature register
+ * @index: Feature register index
+ * @out: Feature register value is written to this pointer
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_features(unsigned long index, unsigned long *out)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_FEATURES, index, &res);
+
+	if (out)
+		*out = res.a1;
+	return res.a0;
+}
+
+/**
+ * rmi_granule_delegate() - Delegate a Granule
+ * @phys: PA of the Granule
+ *
+ * Delegate a Granule for use by the Realm World.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_granule_delegate(unsigned long phys)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_GRANULE_DELEGATE, phys, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_granule_undelegate() - Undelegate a Granule
+ * @phys: PA of the Granule
+ *
+ * Undelegate a Granule to allow use by the Normal World. Will fail if the
+ * Granule is in use.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_granule_undelegate(unsigned long phys)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_GRANULE_UNDELEGATE, phys, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_psci_complete() - Complete pending PSCI command
+ * @calling_rec: PA of the calling REC
+ * @target_rec: PA of the target REC
+ * @status: Status of the PSCI request
+ *
+ * Completes a pending PSCI command which was called with an MPIDR argument, by
+ * providing the corresponding REC.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_psci_complete(unsigned long calling_rec,
+				    unsigned long target_rec,
+				    unsigned long status)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_PSCI_COMPLETE, calling_rec, target_rec,
+			     status, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_realm_activate() - Active a Realm
+ * @rd: PA of the RD
+ *
+ * Mark a Realm as Active signalling that creation is complete and allowing
+ * execution of the Realm.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_realm_activate(unsigned long rd)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REALM_ACTIVATE, rd, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_realm_create() - Create a Realm
+ * @rd: PA of the RD
+ * @params_ptr: PA of Realm parameters
+ *
+ * Create a new Realm using the given parameters.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_realm_create(unsigned long rd, unsigned long params_ptr)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REALM_CREATE, rd, params_ptr, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_realm_destroy() - Destroy a Realm
+ * @rd: PA of the RD
+ *
+ * Destroys a Realm, all objects belonging to the Realm must be destroyed first.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_realm_destroy(unsigned long rd)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REALM_DESTROY, rd, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rec_aux_count() - Get number of auxiliary Granules required
+ * @rd: PA of the RD
+ * @aux_count: Number of pages written to this pointer
+ *
+ * A REC may require extra auxiliary pages to be delegated for the RMM to
+ * store metadata (not visible to the normal world) in. This function provides
+ * the number of pages that are required.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rec_aux_count(unsigned long rd, unsigned long *aux_count)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REC_AUX_COUNT, rd, &res);
+
+	if (aux_count)
+		*aux_count = res.a1;
+	return res.a0;
+}
+
+/**
+ * rmi_rec_create() - Create a REC
+ * @rd: PA of the RD
+ * @rec: PA of the target REC
+ * @params_ptr: PA of REC parameters
+ *
+ * Create a REC using the parameters specified in the struct rec_params pointed
+ * to by @params_ptr.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rec_create(unsigned long rd, unsigned long rec,
+				 unsigned long params_ptr)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REC_CREATE, rd, rec, params_ptr, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rec_destroy() - Destroy a REC
+ * @rec: PA of the target REC
+ *
+ * Destroys a REC. The REC must not be running.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rec_destroy(unsigned long rec)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REC_DESTROY, rec, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rec_enter() - Enter a REC
+ * @rec: PA of the target REC
+ * @run_ptr: PA of RecRun structure
+ *
+ * Starts (or continues) execution within a REC.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rec_enter(unsigned long rec, unsigned long run_ptr)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_REC_ENTER, rec, run_ptr, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_create() - Creates an RTT
+ * @rd: PA of the RD
+ * @rtt: PA of the target RTT
+ * @ipa: Base of the IPA range described by the RTT
+ * @level: Depth of the RTT within the tree
+ *
+ * Creates an RTT (Realm Translation Table) at the specified address and level
+ * within the realm.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_create(unsigned long rd, unsigned long rtt,
+				 unsigned long ipa, long level)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_CREATE, rd, rtt, ipa, level, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_destroy() - Destroy an RTT
+ * @rd: PA of the RD
+ * @ipa: Base of the IPA range described by the RTT
+ * @level: Depth of the RTT within the tree
+ * @out_rtt: Pointer to write the PA of the RTT which was destroyed
+ * @out_top: Pointer to write the top IPA of non-live RTT entries
+ *
+ * Destroys an RTT. The RTT must be empty.
+ *
+ * Return: RMI return code.
+ */
+static inline int rmi_rtt_destroy(unsigned long rd,
+				  unsigned long ipa,
+				  long level,
+				  unsigned long *out_rtt,
+				  unsigned long *out_top)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_DESTROY, rd, ipa, level, &res);
+
+	if (out_rtt)
+		*out_rtt = res.a1;
+	if (out_top)
+		*out_top = res.a2;
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_fold() - Fold an RTT
+ * @rd: PA of the RD
+ * @ipa: Base of the IPA range described by the RTT
+ * @level: Depth of the RTT within the tree
+ * @out_rtt: Pointer to write the PA of the RTT which was destroyed
+ *
+ * Folds an RTT. If all entries with the RTT are 'homogeneous' the RTT can be
+ * folded into the parent and the RTT destroyed.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_fold(unsigned long rd, unsigned long ipa,
+			       long level, unsigned long *out_rtt)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_FOLD, rd, ipa, level, &res);
+
+	if (out_rtt)
+		*out_rtt = res.a1;
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_init_ripas() - Set RIPAS for new Realm
+ * @rd: PA of the RD
+ * @base: Base of target IPA region
+ * @top: Top of target IPA region
+ * @out_top: Top IPA of range whose RIPAS was modified
+ *
+ * Sets the RIPAS of a target IPA range to RAM, for a Realm in the NEW state.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_init_ripas(unsigned long rd, unsigned long base,
+				     unsigned long top, unsigned long *out_top)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_INIT_RIPAS, rd, base, top, &res);
+
+	if (out_top)
+		*out_top = res.a1;
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_map_unprotected() - Map NS pages into a Realm
+ * @rd: PA of the RD
+ * @ipa: Base IPA of the mapping
+ * @level: Depth within the RTT tree
+ * @desc: RTTE descriptor
+ *
+ * Create a mapping from an Unprotected IPA to a Non-secure PA.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_map_unprotected(unsigned long rd,
+					  unsigned long ipa,
+					  long level,
+					  unsigned long desc)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_MAP_UNPROTECTED, rd, ipa, level,
+			     desc, &res);
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_read_entry() - Read an RTTE
+ * @rd: PA of the RD
+ * @ipa: IPA for which to read the RTTE
+ * @level: RTT level at which to read the RTTE
+ * @rtt: Output structure describing the RTTE
+ *
+ * Reads a RTTE (Realm Translation Table Entry).
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_read_entry(unsigned long rd, unsigned long ipa,
+				     long level, struct rtt_entry *rtt)
+{
+	struct arm_smccc_1_2_regs regs = {
+		SMC_RMI_RTT_READ_ENTRY,
+		rd, ipa, level
+	};
+
+	arm_smccc_1_2_smc(&regs, &regs);
+
+	rtt->walk_level = regs.a1;
+	rtt->state = regs.a2 & 0xFF;
+	rtt->desc = regs.a3;
+	rtt->ripas = regs.a4 & 0xFF;
+
+	return regs.a0;
+}
+
+/**
+ * rmi_rtt_set_ripas() - Set RIPAS for an running realm
+ * @rd: PA of the RD
+ * @rec: PA of the REC making the request
+ * @base: Base of target IPA region
+ * @top: Top of target IPA region
+ * @out_top: Pointer to write top IPA of range whose RIPAS was modified
+ *
+ * Completes a request made by the Realm to change the RIPAS of a target IPA
+ * range.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_set_ripas(unsigned long rd, unsigned long rec,
+				    unsigned long base, unsigned long top,
+				    unsigned long *out_top)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_SET_RIPAS, rd, rec, base, top, &res);
+
+	if (out_top)
+		*out_top = res.a1;
+
+	return res.a0;
+}
+
+/**
+ * rmi_rtt_unmap_unprotected() - Remove a NS mapping
+ * @rd: PA of the RD
+ * @ipa: Base IPA of the mapping
+ * @level: Depth within the RTT tree
+ * @out_top: Pointer to write top IPA of non-live RTT entries
+ *
+ * Removes a mapping at an Unprotected IPA.
+ *
+ * Return: RMI return code
+ */
+static inline int rmi_rtt_unmap_unprotected(unsigned long rd,
+					    unsigned long ipa,
+					    long level,
+					    unsigned long *out_top)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_RTT_UNMAP_UNPROTECTED, rd, ipa,
+			     level, &res);
+
+	if (out_top)
+		*out_top = res.a1;
+
+	return res.a0;
+}
+
+#endif
-- 
2.34.1

Re: [PATCH v4 06/43] arm64: RME: Add wrappers for RMI calls

[Suzuki K Poulose]

Hi Steven

On 21/08/2024 16:38, Steven Price wrote:
> The wrappers make the call sites easier to read and deal with the
> boiler plate of handling the error codes from the RMM.
> 

Patch looks good to me, some minor nits below

> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes from v2:
>   * Make output arguments optional.
>   * Mask RIPAS value rmi_rtt_read_entry()
>   * Drop unused rmi_rtt_get_phys()
> ---
>   arch/arm64/include/asm/rmi_cmds.h | 508 ++++++++++++++++++++++++++++++
>   1 file changed, 508 insertions(+)
>   create mode 100644 arch/arm64/include/asm/rmi_cmds.h
> 
> diff --git a/arch/arm64/include/asm/rmi_cmds.h b/arch/arm64/include/asm/rmi_cmds.h
> new file mode 100644
> index 000000000000..5288fed4c11a
> --- /dev/null
> +++ b/arch/arm64/include/asm/rmi_cmds.h
> @@ -0,0 +1,508 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#ifndef __ASM_RMI_CMDS_H
> +#define __ASM_RMI_CMDS_H
> +
> +#include <linux/arm-smccc.h>
> +
> +#include <asm/rmi_smc.h>
> +
> +struct rtt_entry {
> +	unsigned long walk_level;
> +	unsigned long desc;
> +	int state;
> +	int ripas;
> +};
> +
> +/**
> + * rmi_data_create() - Create a Data Granule
> + * @rd: PA of the RD
> + * @data: PA of the target granule
> + * @ipa: IPA at which the granule will be mapped in the guest
> + * @src: PA of the source granule
> + * @flags: RMI_MEASURE_CONTENT if the contents should be measured
> + *
> + * Create a new Data Granule, copying contents from a Non-secure Granule.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_data_create(unsigned long rd, unsigned long data,
> +				  unsigned long ipa, unsigned long src,
> +				  unsigned long flags)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_DATA_CREATE, rd, data, ipa, src,
> +			     flags, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_data_create_unknown() - Create a Data Granule with unknown contents
> + * @rd: PA of the RD
> + * @data: PA of the target granule
> + * @ipa: IPA at which the granule will be mapped in the guest
> + *
> + * Create a new Data Granule with unknown contents
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_data_create_unknown(unsigned long rd,
> +					  unsigned long data,
> +					  unsigned long ipa)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_DATA_CREATE_UNKNOWN, rd, data, ipa, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_data_destroy() - Destroy a Data Granule
> + * @rd: PA of the RD
> + * @ipa: IPA at which the granule is mapped in the guest
> + * @data_out: PA of the granule which was destroyed
> + * @top_out: Top IPA of non-live RTT entries
> + *
> + * Transitions the granule to DESTROYED state, the address cannot be used by
> + * the guest for the lifetime of the Realm.

This may be confusing. Could we extend the above sentence to indicate 
something like:

"Unmap a protected ipa from stage2, transitioning it to DESTROYED.
The IPA cannot be used by the guest unless it is transitioned to
RAM again by the Realm"


> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_data_destroy(unsigned long rd, unsigned long ipa,
> +				   unsigned long *data_out,
> +				   unsigned long *top_out)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_DATA_DESTROY, rd, ipa, &res);
> +
> +	if (data_out)
> +		*data_out = res.a1;
> +	if (top_out)
> +		*top_out = res.a2;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_features() - Read feature register
> + * @index: Feature register index
> + * @out: Feature register value is written to this pointer
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_features(unsigned long index, unsigned long *out)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_FEATURES, index, &res);
> +
> +	if (out)
> +		*out = res.a1;
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_granule_delegate() - Delegate a Granule
> + * @phys: PA of the Granule
> + *
> + * Delegate a Granule for use by the Realm World.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_granule_delegate(unsigned long phys)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_GRANULE_DELEGATE, phys, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_granule_undelegate() - Undelegate a Granule
> + * @phys: PA of the Granule
> + *
> + * Undelegate a Granule to allow use by the Normal World. Will fail if the
> + * Granule is in use.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_granule_undelegate(unsigned long phys)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_GRANULE_UNDELEGATE, phys, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_psci_complete() - Complete pending PSCI command
> + * @calling_rec: PA of the calling REC
> + * @target_rec: PA of the target REC
> + * @status: Status of the PSCI request
> + *
> + * Completes a pending PSCI command which was called with an MPIDR argument, by
> + * providing the corresponding REC.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_psci_complete(unsigned long calling_rec,
> +				    unsigned long target_rec,
> +				    unsigned long status)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_PSCI_COMPLETE, calling_rec, target_rec,
> +			     status, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_realm_activate() - Active a Realm
> + * @rd: PA of the RD
> + *
> + * Mark a Realm as Active signalling that creation is complete and allowing
> + * execution of the Realm.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_realm_activate(unsigned long rd)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REALM_ACTIVATE, rd, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_realm_create() - Create a Realm
> + * @rd: PA of the RD
> + * @params_ptr: PA of Realm parameters
> + *
> + * Create a new Realm using the given parameters.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_realm_create(unsigned long rd, unsigned long params_ptr)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REALM_CREATE, rd, params_ptr, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_realm_destroy() - Destroy a Realm
> + * @rd: PA of the RD
> + *
> + * Destroys a Realm, all objects belonging to the Realm must be destroyed first.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_realm_destroy(unsigned long rd)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REALM_DESTROY, rd, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rec_aux_count() - Get number of auxiliary Granules required
> + * @rd: PA of the RD
> + * @aux_count: Number of pages written to this pointer
> + *
> + * A REC may require extra auxiliary pages to be delegated for the RMM to
> + * store metadata (not visible to the normal world) in. This function provides
> + * the number of pages that are required.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rec_aux_count(unsigned long rd, unsigned long *aux_count)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REC_AUX_COUNT, rd, &res);
> +
> +	if (aux_count)
> +		*aux_count = res.a1;
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rec_create() - Create a REC
> + * @rd: PA of the RD
> + * @rec: PA of the target REC
> + * @params_ptr: PA of REC parameters
> + *
> + * Create a REC using the parameters specified in the struct rec_params pointed
> + * to by @params_ptr.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rec_create(unsigned long rd, unsigned long rec,
> +				 unsigned long params_ptr)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REC_CREATE, rd, rec, params_ptr, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rec_destroy() - Destroy a REC
> + * @rec: PA of the target REC
> + *
> + * Destroys a REC. The REC must not be running.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rec_destroy(unsigned long rec)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REC_DESTROY, rec, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rec_enter() - Enter a REC
> + * @rec: PA of the target REC
> + * @run_ptr: PA of RecRun structure
> + *
> + * Starts (or continues) execution within a REC.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rec_enter(unsigned long rec, unsigned long run_ptr)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_REC_ENTER, rec, run_ptr, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_create() - Creates an RTT
> + * @rd: PA of the RD
> + * @rtt: PA of the target RTT
> + * @ipa: Base of the IPA range described by the RTT
> + * @level: Depth of the RTT within the tree
> + *
> + * Creates an RTT (Realm Translation Table) at the specified address and level
> + * within the realm.

minor nit:

"Creates an RTT (Realm Translation Table) at the specified level for the 
translation of the specified address" ?


> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_create(unsigned long rd, unsigned long rtt,
> +				 unsigned long ipa, long level)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_CREATE, rd, rtt, ipa, level, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_destroy() - Destroy an RTT
> + * @rd: PA of the RD
> + * @ipa: Base of the IPA range described by the RTT
> + * @level: Depth of the RTT within the tree
> + * @out_rtt: Pointer to write the PA of the RTT which was destroyed
> + * @out_top: Pointer to write the top IPA of non-live RTT entries
> + *
> + * Destroys an RTT. The RTT must be empty.

minor nit: To be more precise, "The RTT must be non-live, i.e, none of 
the entries in the table are in ASSIGNED or TABLE state".

e.g, it is perfectly fine to destroy an RTT mapping UNPROTECTED leaf
mappings.

Thanks
Suzuki

> + *
> + * Return: RMI return code.
> + */
> +static inline int rmi_rtt_destroy(unsigned long rd,
> +				  unsigned long ipa,
> +				  long level,
> +				  unsigned long *out_rtt,
> +				  unsigned long *out_top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_DESTROY, rd, ipa, level, &res);
> +
> +	if (out_rtt)
> +		*out_rtt = res.a1;
> +	if (out_top)
> +		*out_top = res.a2;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_fold() - Fold an RTT
> + * @rd: PA of the RD
> + * @ipa: Base of the IPA range described by the RTT
> + * @level: Depth of the RTT within the tree
> + * @out_rtt: Pointer to write the PA of the RTT which was destroyed
> + *
> + * Folds an RTT. If all entries with the RTT are 'homogeneous' the RTT can be
> + * folded into the parent and the RTT destroyed.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_fold(unsigned long rd, unsigned long ipa,
> +			       long level, unsigned long *out_rtt)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_FOLD, rd, ipa, level, &res);
> +
> +	if (out_rtt)
> +		*out_rtt = res.a1;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_init_ripas() - Set RIPAS for new Realm
> + * @rd: PA of the RD
> + * @base: Base of target IPA region
> + * @top: Top of target IPA region
> + * @out_top: Top IPA of range whose RIPAS was modified
> + *
> + * Sets the RIPAS of a target IPA range to RAM, for a Realm in the NEW state.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_init_ripas(unsigned long rd, unsigned long base,
> +				     unsigned long top, unsigned long *out_top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_INIT_RIPAS, rd, base, top, &res);
> +
> +	if (out_top)
> +		*out_top = res.a1;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_map_unprotected() - Map NS pages into a Realm
> + * @rd: PA of the RD
> + * @ipa: Base IPA of the mapping
> + * @level: Depth within the RTT tree
> + * @desc: RTTE descriptor
> + *
> + * Create a mapping from an Unprotected IPA to a Non-secure PA.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_map_unprotected(unsigned long rd,
> +					  unsigned long ipa,
> +					  long level,
> +					  unsigned long desc)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_MAP_UNPROTECTED, rd, ipa, level,
> +			     desc, &res);
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_read_entry() - Read an RTTE
> + * @rd: PA of the RD
> + * @ipa: IPA for which to read the RTTE
> + * @level: RTT level at which to read the RTTE
> + * @rtt: Output structure describing the RTTE
> + *
> + * Reads a RTTE (Realm Translation Table Entry).
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_read_entry(unsigned long rd, unsigned long ipa,
> +				     long level, struct rtt_entry *rtt)
> +{
> +	struct arm_smccc_1_2_regs regs = {
> +		SMC_RMI_RTT_READ_ENTRY,
> +		rd, ipa, level
> +	};
> +
> +	arm_smccc_1_2_smc(&regs, &regs);
> +
> +	rtt->walk_level = regs.a1;
> +	rtt->state = regs.a2 & 0xFF;
> +	rtt->desc = regs.a3;
> +	rtt->ripas = regs.a4 & 0xFF;
> +
> +	return regs.a0;
> +}
> +
> +/**
> + * rmi_rtt_set_ripas() - Set RIPAS for an running realm
> + * @rd: PA of the RD
> + * @rec: PA of the REC making the request
> + * @base: Base of target IPA region
> + * @top: Top of target IPA region
> + * @out_top: Pointer to write top IPA of range whose RIPAS was modified
> + *
> + * Completes a request made by the Realm to change the RIPAS of a target IPA
> + * range.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_set_ripas(unsigned long rd, unsigned long rec,
> +				    unsigned long base, unsigned long top,
> +				    unsigned long *out_top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_SET_RIPAS, rd, rec, base, top, &res);
> +
> +	if (out_top)
> +		*out_top = res.a1;
> +
> +	return res.a0;
> +}
> +
> +/**
> + * rmi_rtt_unmap_unprotected() - Remove a NS mapping
> + * @rd: PA of the RD
> + * @ipa: Base IPA of the mapping
> + * @level: Depth within the RTT tree
> + * @out_top: Pointer to write top IPA of non-live RTT entries
> + *
> + * Removes a mapping at an Unprotected IPA.
> + *
> + * Return: RMI return code
> + */
> +static inline int rmi_rtt_unmap_unprotected(unsigned long rd,
> +					    unsigned long ipa,
> +					    long level,
> +					    unsigned long *out_top)
> +{
> +	struct arm_smccc_res res;
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_RTT_UNMAP_UNPROTECTED, rd, ipa,
> +			     level, &res);
> +
> +	if (out_top)
> +		*out_top = res.a1;
> +
> +	return res.a0;
> +}
> +
> +#endif

[PATCH v4 07/43] arm64: RME: Check for RME support at KVM init

[Steven Price]

Query the RMI version number and check if it is a compatible version. A
static key is also provided to signal that a supported RMM is available.

Functions are provided to query if a VM or VCPU is a realm (or rec)
which currently will always return false.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Drop return value from kvm_init_rme(), it was always 0.
 * Rely on the RMM return value to identify whether the RSI ABI is
   compatible.
---
 arch/arm64/include/asm/kvm_emulate.h | 17 +++++++++
 arch/arm64/include/asm/kvm_host.h    |  4 ++
 arch/arm64/include/asm/kvm_rme.h     | 56 ++++++++++++++++++++++++++++
 arch/arm64/include/asm/virt.h        |  1 +
 arch/arm64/kvm/Makefile              |  3 +-
 arch/arm64/kvm/arm.c                 |  6 +++
 arch/arm64/kvm/rme.c                 | 50 +++++++++++++++++++++++++
 7 files changed, 136 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/include/asm/kvm_rme.h
 create mode 100644 arch/arm64/kvm/rme.c

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index a601a9305b10..c7bfb6788c96 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -693,4 +693,21 @@ static inline bool guest_hyp_sve_traps_enabled(const struct kvm_vcpu *vcpu)
 	return __guest_hyp_cptr_xen_trap_enabled(vcpu, ZEN);
 }
 
+static inline bool kvm_is_realm(struct kvm *kvm)
+{
+	if (static_branch_unlikely(&kvm_rme_is_available) && kvm)
+		return kvm->arch.is_realm;
+	return false;
+}
+
+static inline enum realm_state kvm_realm_state(struct kvm *kvm)
+{
+	return READ_ONCE(kvm->arch.realm.state);
+}
+
+static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
+{
+	return false;
+}
+
 #endif /* __ARM64_KVM_EMULATE_H__ */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index a33f5996ca9f..e36be05b97f8 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -27,6 +27,7 @@
 #include <asm/fpsimd.h>
 #include <asm/kvm.h>
 #include <asm/kvm_asm.h>
+#include <asm/kvm_rme.h>
 #include <asm/vncr_mapping.h>
 
 #define __KVM_HAVE_ARCH_INTC_INITIALIZED
@@ -375,6 +376,9 @@ struct kvm_arch {
 	 * the associated pKVM instance in the hypervisor.
 	 */
 	struct kvm_protected_vm pkvm;
+
+	bool is_realm;
+	struct realm realm;
 };
 
 struct kvm_vcpu_fault_info {
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
new file mode 100644
index 000000000000..69af5c3a1e44
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#ifndef __ASM_KVM_RME_H
+#define __ASM_KVM_RME_H
+
+/**
+ * enum realm_state - State of a Realm
+ */
+enum realm_state {
+	/**
+	 * @REALM_STATE_NONE:
+	 *      Realm has not yet been created. rmi_realm_create() may be
+	 *      called to create the realm.
+	 */
+	REALM_STATE_NONE,
+	/**
+	 * @REALM_STATE_NEW:
+	 *      Realm is under construction, not eligible for execution. Pages
+	 *      may be populated with rmi_data_create().
+	 */
+	REALM_STATE_NEW,
+	/**
+	 * @REALM_STATE_ACTIVE:
+	 *      Realm has been created and is eligible for execution with
+	 *      rmi_rec_enter(). Pages may no longer be populated with
+	 *      rmi_data_create().
+	 */
+	REALM_STATE_ACTIVE,
+	/**
+	 * @REALM_STATE_DYING:
+	 *      Realm is in the process of being destroyed or has already been
+	 *      destroyed.
+	 */
+	REALM_STATE_DYING,
+	/**
+	 * @REALM_STATE_DEAD:
+	 *      Realm has been destroyed.
+	 */
+	REALM_STATE_DEAD
+};
+
+/**
+ * struct realm - Additional per VM data for a Realm
+ *
+ * @state: The lifetime state machine for the realm
+ */
+struct realm {
+	enum realm_state state;
+};
+
+void kvm_init_rme(void);
+
+#endif
diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index ebf4a9f943ed..e45d47156dcf 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h
@@ -81,6 +81,7 @@ void __hyp_reset_vectors(void);
 bool is_kvm_arm_initialised(void);
 
 DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
+DECLARE_STATIC_KEY_FALSE(kvm_rme_is_available);
 
 static inline bool is_pkvm_initialized(void)
 {
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index a6497228c5a8..5e79e5eee88d 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -20,7 +20,8 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 vgic/vgic-v3.o vgic/vgic-v4.o \
 	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
 	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
-	 vgic/vgic-its.o vgic/vgic-debug.o
+	 vgic/vgic-its.o vgic/vgic-debug.o \
+	 rme.o
 
 kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
 kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a7ca776b51ec..71ffcc766eeb 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -40,6 +40,7 @@
 #include <asm/kvm_nested.h>
 #include <asm/kvm_pkvm.h>
 #include <asm/kvm_ptrauth.h>
+#include <asm/kvm_rme.h>
 #include <asm/sections.h>
 
 #include <kvm/arm_hypercalls.h>
@@ -57,6 +58,8 @@ enum kvm_wfx_trap_policy {
 static enum kvm_wfx_trap_policy kvm_wfi_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK;
 static enum kvm_wfx_trap_policy kvm_wfe_trap_policy __read_mostly = KVM_WFX_NOTRAP_SINGLE_TASK;
 
+DEFINE_STATIC_KEY_FALSE(kvm_rme_is_available);
+
 DECLARE_KVM_HYP_PER_CPU(unsigned long, kvm_hyp_vector);
 
 DEFINE_PER_CPU(unsigned long, kvm_arm_hyp_stack_page);
@@ -2788,6 +2791,9 @@ static __init int kvm_arm_init(void)
 
 	in_hyp_mode = is_kernel_in_hyp_mode();
 
+	if (in_hyp_mode)
+		kvm_init_rme();
+
 	if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE) ||
 	    cpus_have_final_cap(ARM64_WORKAROUND_1508412))
 		kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
new file mode 100644
index 000000000000..418685fbf6ed
--- /dev/null
+++ b/arch/arm64/kvm/rme.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#include <linux/kvm_host.h>
+
+#include <asm/rmi_cmds.h>
+#include <asm/virt.h>
+
+static int rmi_check_version(void)
+{
+	struct arm_smccc_res res;
+	int version_major, version_minor;
+	unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION,
+						     RMI_ABI_MINOR_VERSION);
+
+	arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res);
+
+	if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
+		return -ENXIO;
+
+	version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1);
+	version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1);
+
+	if (res.a0 != RMI_SUCCESS) {
+		kvm_err("Unsupported RMI ABI (v%d.%d) host supports v%d.%d\n",
+			version_major, version_minor,
+			RMI_ABI_MAJOR_VERSION,
+			RMI_ABI_MINOR_VERSION);
+		return -ENXIO;
+	}
+
+	kvm_info("RMI ABI version %d.%d\n", version_major, version_minor);
+
+	return 0;
+}
+
+void kvm_init_rme(void)
+{
+	if (PAGE_SIZE != SZ_4K)
+		/* Only 4k page size on the host is supported */
+		return;
+
+	if (rmi_check_version())
+		/* Continue without realm support */
+		return;
+
+	/* Future patch will enable static branch kvm_rme_is_available */
+}
-- 
2.34.1

Re: [PATCH v4 07/43] arm64: RME: Check for RME support at KVM init

[Gavin Shan]

On 8/22/24 1:38 AM, Steven Price wrote:
> Query the RMI version number and check if it is a compatible version. A
> static key is also provided to signal that a supported RMM is available.
> 
> Functions are provided to query if a VM or VCPU is a realm (or rec)
> which currently will always return false.
> 
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>   * Drop return value from kvm_init_rme(), it was always 0.
>   * Rely on the RMM return value to identify whether the RSI ABI is
>     compatible.
> ---
>   arch/arm64/include/asm/kvm_emulate.h | 17 +++++++++
>   arch/arm64/include/asm/kvm_host.h    |  4 ++
>   arch/arm64/include/asm/kvm_rme.h     | 56 ++++++++++++++++++++++++++++
>   arch/arm64/include/asm/virt.h        |  1 +
>   arch/arm64/kvm/Makefile              |  3 +-
>   arch/arm64/kvm/arm.c                 |  6 +++
>   arch/arm64/kvm/rme.c                 | 50 +++++++++++++++++++++++++
>   7 files changed, 136 insertions(+), 1 deletion(-)
>   create mode 100644 arch/arm64/include/asm/kvm_rme.h
>   create mode 100644 arch/arm64/kvm/rme.c
> 

[...]

> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> new file mode 100644
> index 000000000000..418685fbf6ed
> --- /dev/null
> +++ b/arch/arm64/kvm/rme.c
> @@ -0,0 +1,50 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2023 ARM Ltd.
> + */
> +
> +#include <linux/kvm_host.h>
> +
> +#include <asm/rmi_cmds.h>
> +#include <asm/virt.h>
> +
> +static int rmi_check_version(void)
> +{
> +	struct arm_smccc_res res;
> +	int version_major, version_minor;
> +	unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION,
> +						     RMI_ABI_MINOR_VERSION);
> +
> +	arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res);
> +
> +	if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
> +		return -ENXIO;
> +
> +	version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1);
> +	version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1);
> +
> +	if (res.a0 != RMI_SUCCESS) {
> +		kvm_err("Unsupported RMI ABI (v%d.%d) host supports v%d.%d\n",
> +			version_major, version_minor,
> +			RMI_ABI_MAJOR_VERSION,
> +			RMI_ABI_MINOR_VERSION);

This message is perhaps something like below since a range of versions can be
supported by one particular RMM release.

     kvm_err("Unsupported RMI ABI v%d.%d. Host supports v%ld.%ld - v%ld.%ld\n",
             RMI_ABI_MAJOR_VERSION, RMI_ABI_MINOR_VERSION,
             RMI_ABI_VERSION_GET_MAJOR(res.a1), RMI_ABI_VERSION_GET_MINOR(res.a1),
             RMI_ABI_VERSION_GET_MAJOR(res.a2), RMI_ABI_VERSION_GET_MINOR(res.a2));

> +		return -ENXIO;
> +	}
> +
> +	kvm_info("RMI ABI version %d.%d\n", version_major, version_minor);
> +

We probably need to print the requested version, instead of the lower implemented
version, if I'm correct. At present, both of them have been fixed to v1.0 and we
don't have a problem though.

         kvm_info("RMI ABI version v%d.%d\n", RMI_ABI_MAJOR_VERSION, RMI_ABI_MINOR_VERSION);

> +	return 0;
> +}
> +

Thanks,
Gavin

Re: [PATCH v4 07/43] arm64: RME: Check for RME support at KVM init

[Steven Price]

Hi Gavin,

On 12/09/2024 09:49, Gavin Shan wrote:
> On 8/22/24 1:38 AM, Steven Price wrote:
>> Query the RMI version number and check if it is a compatible version. A
>> static key is also provided to signal that a supported RMM is available.
>>
>> Functions are provided to query if a VM or VCPU is a realm (or rec)
>> which currently will always return false.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>   * Drop return value from kvm_init_rme(), it was always 0.
>>   * Rely on the RMM return value to identify whether the RSI ABI is
>>     compatible.
>> ---
>>   arch/arm64/include/asm/kvm_emulate.h | 17 +++++++++
>>   arch/arm64/include/asm/kvm_host.h    |  4 ++
>>   arch/arm64/include/asm/kvm_rme.h     | 56 ++++++++++++++++++++++++++++
>>   arch/arm64/include/asm/virt.h        |  1 +
>>   arch/arm64/kvm/Makefile              |  3 +-
>>   arch/arm64/kvm/arm.c                 |  6 +++
>>   arch/arm64/kvm/rme.c                 | 50 +++++++++++++++++++++++++
>>   7 files changed, 136 insertions(+), 1 deletion(-)
>>   create mode 100644 arch/arm64/include/asm/kvm_rme.h
>>   create mode 100644 arch/arm64/kvm/rme.c
>>
> 
> [...]
> 
>> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
>> new file mode 100644
>> index 000000000000..418685fbf6ed
>> --- /dev/null
>> +++ b/arch/arm64/kvm/rme.c
>> @@ -0,0 +1,50 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (C) 2023 ARM Ltd.
>> + */
>> +
>> +#include <linux/kvm_host.h>
>> +
>> +#include <asm/rmi_cmds.h>
>> +#include <asm/virt.h>
>> +
>> +static int rmi_check_version(void)
>> +{
>> +    struct arm_smccc_res res;
>> +    int version_major, version_minor;
>> +    unsigned long host_version = RMI_ABI_VERSION(RMI_ABI_MAJOR_VERSION,
>> +                             RMI_ABI_MINOR_VERSION);
>> +
>> +    arm_smccc_1_1_invoke(SMC_RMI_VERSION, host_version, &res);
>> +
>> +    if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
>> +        return -ENXIO;
>> +
>> +    version_major = RMI_ABI_VERSION_GET_MAJOR(res.a1);
>> +    version_minor = RMI_ABI_VERSION_GET_MINOR(res.a1);
>> +
>> +    if (res.a0 != RMI_SUCCESS) {
>> +        kvm_err("Unsupported RMI ABI (v%d.%d) host supports v%d.%d\n",
>> +            version_major, version_minor,
>> +            RMI_ABI_MAJOR_VERSION,
>> +            RMI_ABI_MINOR_VERSION);
> 
> This message is perhaps something like below since a range of versions
> can be
> supported by one particular RMM release.
> 
>     kvm_err("Unsupported RMI ABI v%d.%d. Host supports v%ld.%ld -
> v%ld.%ld\n",
>             RMI_ABI_MAJOR_VERSION, RMI_ABI_MINOR_VERSION,
>             RMI_ABI_VERSION_GET_MAJOR(res.a1),
> RMI_ABI_VERSION_GET_MINOR(res.a1),
>             RMI_ABI_VERSION_GET_MAJOR(res.a2),
> RMI_ABI_VERSION_GET_MINOR(res.a2));
> 
>> +        return -ENXIO;
>> +    }
>> +
>> +    kvm_info("RMI ABI version %d.%d\n", version_major, version_minor);
>> +
> 
> We probably need to print the requested version, instead of the lower
> implemented
> version, if I'm correct. At present, both of them have been fixed to
> v1.0 and we
> don't have a problem though.

The RSI_VERSION command is somewhat complex. The RMM returns both a
"higher revision" and a "lower revision". The higher revision is the
highest interface revision supported by the RMM - and not especially
useful at least for the moment when Linux is only aiming for v1.0. So
we're currently just reporting the "lower revision" in the outputs.

There are three possibilities explained in the spec:

a) The RMM is compatible (status code is RSI_SUCCESS). From the spec
"The lower revision is equal to the requested revision". So this last
print will indeed output the requested revision.

b) The RMM doesn't support the requested revision, it supports an older
revision. In this case "The lower revision is the highest interface
revision which is both less than the requested revision and
supported by the RMM". Of course when we're requesting v1.0 this
situation should never occur, but generally we'd expect to negotiate the
lower revision if possible so this is the useful information to output.

c) The RMM does not support the requested revision, it supports a newer
revision. From the spec "The lower revision is equal to the higher
revision". So there's no point outputting both.

So situation (b) is the only case where the higher revision is
interesting. But it's only useful in a situation like:

 * Linux supports v1.1 and v2.0 (and maybe v1.0).
 * Linux prefers v1.1 over v2.0 (and v2.0 over v1.0).
 * Linux therefore requests v1.1.
 * The RMM supports v1.0 and v2.0 (but not v1.1) and so returns failure.
 * lower revision: v1.0
 * higher revision: v2.0

Linux can then use the higher revision field to detect that it can try
again with v2.0.

My expectation is that newer revisions will be preferred and so Linux
will always start by requesting the newest revision it supports (so
"higher revision" will be irrelevant). But it's there so we can support
a scenario like above.

We could output the higher revision just for information, a form of
"hey, your RMM is newer than Linux" - but I'm not sure I see the point.

Steve

>         kvm_info("RMI ABI version v%d.%d\n", RMI_ABI_MAJOR_VERSION,
> RMI_ABI_MINOR_VERSION);
> 
>> +    return 0;
>> +}
>> +
> 
> Thanks,
> Gavin
> 

[PATCH v4 08/43] arm64: RME: Define the user ABI

[Steven Price]

There is one (multiplexed) CAP which can be used to create, populate and
then activate the realm.

Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 Documentation/virt/kvm/api.rst    |  1 +
 arch/arm64/include/uapi/asm/kvm.h | 49 +++++++++++++++++++++++++++++++
 include/uapi/linux/kvm.h          | 12 ++++++++
 3 files changed, 62 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index fe722c5dada9..849ddd2735ca 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -5073,6 +5073,7 @@ Recognised values for feature:
 
   =====      ===========================================
   arm64      KVM_ARM_VCPU_SVE (requires KVM_CAP_ARM_SVE)
+  arm64      KVM_ARM_VCPU_REC (requires KVM_CAP_ARM_RME)
   =====      ===========================================
 
 Finalizes the configuration of the specified vcpu feature.
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 964df31da975..080331008b79 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -108,6 +108,7 @@ struct kvm_regs {
 #define KVM_ARM_VCPU_PTRAUTH_ADDRESS	5 /* VCPU uses address authentication */
 #define KVM_ARM_VCPU_PTRAUTH_GENERIC	6 /* VCPU uses generic authentication */
 #define KVM_ARM_VCPU_HAS_EL2		7 /* Support nested virtualization */
+#define KVM_ARM_VCPU_REC		8 /* VCPU REC state as part of Realm */
 
 struct kvm_vcpu_init {
 	__u32 target;
@@ -418,6 +419,54 @@ enum {
 #define   KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES	3
 #define   KVM_DEV_ARM_ITS_CTRL_RESET		4
 
+/* KVM_CAP_ARM_RME on VM fd */
+#define KVM_CAP_ARM_RME_CONFIG_REALM		0
+#define KVM_CAP_ARM_RME_CREATE_RD		1
+#define KVM_CAP_ARM_RME_INIT_IPA_REALM		2
+#define KVM_CAP_ARM_RME_POPULATE_REALM		3
+#define KVM_CAP_ARM_RME_ACTIVATE_REALM		4
+
+#define KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA256		0
+#define KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA512		1
+
+#define KVM_CAP_ARM_RME_RPV_SIZE 64
+
+/* List of configuration items accepted for KVM_CAP_ARM_RME_CONFIG_REALM */
+#define KVM_CAP_ARM_RME_CFG_RPV			0
+#define KVM_CAP_ARM_RME_CFG_HASH_ALGO		1
+
+struct kvm_cap_arm_rme_config_item {
+	__u32 cfg;
+	union {
+		/* cfg == KVM_CAP_ARM_RME_CFG_RPV */
+		struct {
+			__u8	rpv[KVM_CAP_ARM_RME_RPV_SIZE];
+		};
+
+		/* cfg == KVM_CAP_ARM_RME_CFG_HASH_ALGO */
+		struct {
+			__u32	hash_algo;
+		};
+
+		/* Fix the size of the union */
+		__u8	reserved[256];
+	};
+};
+
+#define KVM_ARM_RME_POPULATE_FLAGS_MEASURE	BIT(0)
+struct kvm_cap_arm_rme_populate_realm_args {
+	__u64 populate_ipa_base;
+	__u64 populate_ipa_size;
+	__u32 flags;
+	__u32 reserved[3];
+};
+
+struct kvm_cap_arm_rme_init_ipa_args {
+	__u64 init_ipa_base;
+	__u64 init_ipa_size;
+	__u32 reserved[4];
+};
+
 /* Device Control API on vcpu fd */
 #define KVM_ARM_VCPU_PMU_V3_CTRL	0
 #define   KVM_ARM_VCPU_PMU_V3_IRQ	0
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 637efc055145..b3884757739d 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -934,6 +934,8 @@ struct kvm_enable_cap {
 #define KVM_CAP_X86_APIC_BUS_CYCLES_NS 237
 #define KVM_CAP_X86_GUEST_MODE 238
 
+#define KVM_CAP_ARM_RME 300 /* FIXME: Large number to prevent conflicts */
+
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
 	__u32 pin;
@@ -1573,4 +1575,14 @@ struct kvm_pre_fault_memory {
 	__u64 padding[5];
 };
 
+/* Available with KVM_CAP_ARM_RME, only for VMs with KVM_VM_TYPE_ARM_REALM  */
+struct kvm_arm_rmm_psci_complete {
+	__u64 target_mpidr;
+	__u32 psci_status;
+	__u32 padding[3];
+};
+
+/* FIXME: Update nr (0xd2) when merging */
+#define KVM_ARM_VCPU_RMM_PSCI_COMPLETE	_IOW(KVMIO, 0xd2, struct kvm_arm_rmm_psci_complete)
+
 #endif /* __LINUX_KVM_H */
-- 
2.34.1

[PATCH v4 09/43] arm64: RME: ioctls to create and configure realms

[Steven Price]

Add the KVM_CAP_ARM_RME_CREATE_RD ioctl to create a realm. This involves
delegating pages to the RMM to hold the Realm Descriptor (RD) and for
the base level of the Realm Translation Tables (RTT). A VMID also need
to be picked, since the RMM has a separate VMID address space a
dedicated allocator is added for this purpose.

KVM_CAP_ARM_RME_CONFIG_REALM is provided to allow configuring the realm
before it is created. Configuration options can be classified as:

 1. Parameters specific to the Realm stage2 (e.g. IPA Size, vmid, stage2
    entry level, entry level RTTs, number of RTTs in start level, LPA2)
    Most of these are not measured by RMM and comes from KVM book
    keeping.

 2. Parameters controlling "Arm Architecture features for the VM". (e.g.
    SVE VL, PMU counters, number of HW BRPs/WPs), configured by the VMM
    using the "user ID register write" mechanism. These will be
    supported in the later patches.

 3. Parameters are not part of the core Arm architecture but defined
    by the RMM spec (e.g. Hash algorithm for measurement,
    Personalisation value). These are programmed via
    KVM_CAP_ARM_RME_CONFIG_REALM.

For the IPA size there is the possibility that the RMM supports a
different size to the IPA size supported by KVM for normal guests. At
the moment the 'normal limit' is exposed by KVM_CAP_ARM_VM_IPA_SIZE and
the IPA size is configured by the bottom bits of vm_type in
KVM_CREATE_VM. This means that it isn't easy for the VMM to discover
what IPA sizes are supported for Realm guests. Since the IPA is part of
the measurement of the realm guest the current expectation is that the
VMM will be required to pick the IPA size demanded by attestation and
therefore simply failing if this isn't available is fine. An option
would be to expose a new capability ioctl to obtain the RMM's maximum
IPA size if this is needed in the future.

Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Improved commit description.
 * Improved return failures for rmi_check_version().
 * Clear contents of PGD after it has been undelegated in case the RMM
   left stale data.
 * Minor changes to reflect changes in previous patches.
---
 arch/arm64/include/asm/kvm_emulate.h |   5 +
 arch/arm64/include/asm/kvm_rme.h     |  19 ++
 arch/arm64/kvm/arm.c                 |  18 ++
 arch/arm64/kvm/mmu.c                 |  20 +-
 arch/arm64/kvm/rme.c                 | 283 +++++++++++++++++++++++++++
 5 files changed, 341 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index c7bfb6788c96..5edcfb1b6c68 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -705,6 +705,11 @@ static inline enum realm_state kvm_realm_state(struct kvm *kvm)
 	return READ_ONCE(kvm->arch.realm.state);
 }
 
+static inline bool kvm_realm_is_created(struct kvm *kvm)
+{
+	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
+}
+
 static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
 {
 	return false;
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 69af5c3a1e44..209cd99f03dd 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -6,6 +6,8 @@
 #ifndef __ASM_KVM_RME_H
 #define __ASM_KVM_RME_H
 
+#include <uapi/linux/kvm.h>
+
 /**
  * enum realm_state - State of a Realm
  */
@@ -46,11 +48,28 @@ enum realm_state {
  * struct realm - Additional per VM data for a Realm
  *
  * @state: The lifetime state machine for the realm
+ * @rd: Kernel mapping of the Realm Descriptor (RD)
+ * @params: Parameters for the RMI_REALM_CREATE command
+ * @num_aux: The number of auxiliary pages required by the RMM
+ * @vmid: VMID to be used by the RMM for the realm
+ * @ia_bits: Number of valid Input Address bits in the IPA
  */
 struct realm {
 	enum realm_state state;
+
+	void *rd;
+	struct realm_params *params;
+
+	unsigned long num_aux;
+	unsigned int vmid;
+	unsigned int ia_bits;
 };
 
 void kvm_init_rme(void);
+u32 kvm_realm_ipa_limit(void);
+
+int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
+int kvm_init_realm_vm(struct kvm *kvm);
+void kvm_destroy_realm(struct kvm *kvm);
 
 #endif
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 71ffcc766eeb..15c7c2cabbf7 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -152,6 +152,13 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
 		}
 		mutex_unlock(&kvm->slots_lock);
 		break;
+	case KVM_CAP_ARM_RME:
+		if (!kvm_is_realm(kvm))
+			return -EINVAL;
+		mutex_lock(&kvm->lock);
+		r = kvm_realm_enable_cap(kvm, cap);
+		mutex_unlock(&kvm->lock);
+		break;
 	default:
 		break;
 	}
@@ -213,6 +220,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 	bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES);
 
+	/* Initialise the realm bits after the generic bits are enabled */
+	if (kvm_is_realm(kvm)) {
+		ret = kvm_init_realm_vm(kvm);
+		if (ret)
+			goto err_free_cpumask;
+	}
+
 	return 0;
 
 err_free_cpumask:
@@ -271,6 +285,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
 	kvm_unshare_hyp(kvm, kvm + 1);
 
 	kvm_arm_teardown_hypercalls(kvm);
+	kvm_destroy_realm(kvm);
 }
 
 static bool kvm_has_full_ptr_auth(void)
@@ -418,6 +433,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES:
 		r = BIT(0);
 		break;
+	case KVM_CAP_ARM_RME:
+		r = static_key_enabled(&kvm_rme_is_available);
+		break;
 	default:
 		r = 0;
 	}
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 6981b1bc0946..2257a3b4fb06 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -862,11 +862,16 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
 	.icache_inval_pou	= invalidate_icache_guest_page,
 };
 
-static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
+static int kvm_init_ipa_range(struct kvm *kvm,
+			      struct kvm_s2_mmu *mmu, unsigned long type)
 {
 	u32 kvm_ipa_limit = get_kvm_ipa_limit();
 	u64 mmfr0, mmfr1;
 	u32 phys_shift;
+	u32 ipa_limit = kvm_ipa_limit;
+
+	if (kvm_is_realm(kvm))
+		ipa_limit = kvm_realm_ipa_limit();
 
 	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
 		return -EINVAL;
@@ -875,12 +880,12 @@ static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
 	if (is_protected_kvm_enabled()) {
 		phys_shift = kvm_ipa_limit;
 	} else if (phys_shift) {
-		if (phys_shift > kvm_ipa_limit ||
+		if (phys_shift > ipa_limit ||
 		    phys_shift < ARM64_MIN_PARANGE_BITS)
 			return -EINVAL;
 	} else {
 		phys_shift = KVM_PHYS_SHIFT;
-		if (phys_shift > kvm_ipa_limit) {
+		if (phys_shift > ipa_limit) {
 			pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
 				     current->comm);
 			return -EINVAL;
@@ -932,7 +937,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 		return -EINVAL;
 	}
 
-	err = kvm_init_ipa_range(mmu, type);
+	err = kvm_init_ipa_range(kvm, mmu, type);
 	if (err)
 		return err;
 
@@ -1055,6 +1060,13 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 	struct kvm_pgtable *pgt = NULL;
 
 	write_lock(&kvm->mmu_lock);
+	if (kvm_is_realm(kvm) &&
+	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
+	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
+		/* Tearing down RTTs will be added in a later patch */
+		write_unlock(&kvm->mmu_lock);
+		return;
+	}
 	pgt = mmu->pgt;
 	if (pgt) {
 		mmu->pgd_phys = 0;
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 418685fbf6ed..4d21ec5f2910 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -5,9 +5,20 @@
 
 #include <linux/kvm_host.h>
 
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_mmu.h>
 #include <asm/rmi_cmds.h>
 #include <asm/virt.h>
 
+#include <asm/kvm_pgtable.h>
+
+static unsigned long rmm_feat_reg0;
+
+static bool rme_supports(unsigned long feature)
+{
+	return !!u64_get_bits(rmm_feat_reg0, feature);
+}
+
 static int rmi_check_version(void)
 {
 	struct arm_smccc_res res;
@@ -36,6 +47,272 @@ static int rmi_check_version(void)
 	return 0;
 }
 
+u32 kvm_realm_ipa_limit(void)
+{
+	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
+}
+
+static int get_start_level(struct realm *realm)
+{
+	return 4 - stage2_pgtable_levels(realm->ia_bits);
+}
+
+static int realm_create_rd(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+	struct realm_params *params = realm->params;
+	void *rd = NULL;
+	phys_addr_t rd_phys, params_phys;
+	struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
+	int i, r;
+
+	if (WARN_ON(realm->rd) || WARN_ON(!realm->params))
+		return -EEXIST;
+
+	rd = (void *)__get_free_page(GFP_KERNEL);
+	if (!rd)
+		return -ENOMEM;
+
+	rd_phys = virt_to_phys(rd);
+	if (rmi_granule_delegate(rd_phys)) {
+		r = -ENXIO;
+		goto free_rd;
+	}
+
+	for (i = 0; i < pgt->pgd_pages; i++) {
+		phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
+
+		if (rmi_granule_delegate(pgd_phys)) {
+			r = -ENXIO;
+			goto out_undelegate_tables;
+		}
+	}
+
+	realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
+
+	params->s2sz = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
+	params->rtt_level_start = get_start_level(realm);
+	params->rtt_num_start = pgt->pgd_pages;
+	params->rtt_base = kvm->arch.mmu.pgd_phys;
+	params->vmid = realm->vmid;
+
+	params_phys = virt_to_phys(params);
+
+	if (rmi_realm_create(rd_phys, params_phys)) {
+		r = -ENXIO;
+		goto out_undelegate_tables;
+	}
+
+	realm->rd = rd;
+
+	if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
+		WARN_ON(rmi_realm_destroy(rd_phys));
+		goto out_undelegate_tables;
+	}
+
+	return 0;
+
+out_undelegate_tables:
+	while (--i >= 0) {
+		phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
+
+		WARN_ON(rmi_granule_undelegate(pgd_phys));
+	}
+	WARN_ON(rmi_granule_undelegate(rd_phys));
+free_rd:
+	free_page((unsigned long)rd);
+	return r;
+}
+
+/* Protects access to rme_vmid_bitmap */
+static DEFINE_SPINLOCK(rme_vmid_lock);
+static unsigned long *rme_vmid_bitmap;
+
+static int rme_vmid_init(void)
+{
+	unsigned int vmid_count = 1 << kvm_get_vmid_bits();
+
+	rme_vmid_bitmap = bitmap_zalloc(vmid_count, GFP_KERNEL);
+	if (!rme_vmid_bitmap) {
+		kvm_err("%s: Couldn't allocate rme vmid bitmap\n", __func__);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int rme_vmid_reserve(void)
+{
+	int ret;
+	unsigned int vmid_count = 1 << kvm_get_vmid_bits();
+
+	spin_lock(&rme_vmid_lock);
+	ret = bitmap_find_free_region(rme_vmid_bitmap, vmid_count, 0);
+	spin_unlock(&rme_vmid_lock);
+
+	return ret;
+}
+
+static void rme_vmid_release(unsigned int vmid)
+{
+	spin_lock(&rme_vmid_lock);
+	bitmap_release_region(rme_vmid_bitmap, vmid, 0);
+	spin_unlock(&rme_vmid_lock);
+}
+
+static int kvm_create_realm(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+	int ret;
+
+	if (!kvm_is_realm(kvm))
+		return -EINVAL;
+	if (kvm_realm_is_created(kvm))
+		return -EEXIST;
+
+	ret = rme_vmid_reserve();
+	if (ret < 0)
+		return ret;
+	realm->vmid = ret;
+
+	ret = realm_create_rd(kvm);
+	if (ret) {
+		rme_vmid_release(realm->vmid);
+		return ret;
+	}
+
+	WRITE_ONCE(realm->state, REALM_STATE_NEW);
+
+	/* The realm is up, free the parameters.  */
+	free_page((unsigned long)realm->params);
+	realm->params = NULL;
+
+	return 0;
+}
+
+static int config_realm_hash_algo(struct realm *realm,
+				  struct kvm_cap_arm_rme_config_item *cfg)
+{
+	switch (cfg->hash_algo) {
+	case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA256:
+		if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_256))
+			return -EINVAL;
+		break;
+	case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA512:
+		if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_512))
+			return -EINVAL;
+		break;
+	default:
+		return -EINVAL;
+	}
+	realm->params->hash_algo = cfg->hash_algo;
+	return 0;
+}
+
+static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap)
+{
+	struct kvm_cap_arm_rme_config_item cfg;
+	struct realm *realm = &kvm->arch.realm;
+	int r = 0;
+
+	if (kvm_realm_is_created(kvm))
+		return -EBUSY;
+
+	if (copy_from_user(&cfg, (void __user *)cap->args[1], sizeof(cfg)))
+		return -EFAULT;
+
+	switch (cfg.cfg) {
+	case KVM_CAP_ARM_RME_CFG_RPV:
+		memcpy(&realm->params->rpv, &cfg.rpv, sizeof(cfg.rpv));
+		break;
+	case KVM_CAP_ARM_RME_CFG_HASH_ALGO:
+		r = config_realm_hash_algo(realm, &cfg);
+		break;
+	default:
+		r = -EINVAL;
+	}
+
+	return r;
+}
+
+int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
+{
+	int r = 0;
+
+	if (!kvm_is_realm(kvm))
+		return -EINVAL;
+
+	switch (cap->args[0]) {
+	case KVM_CAP_ARM_RME_CONFIG_REALM:
+		r = kvm_rme_config_realm(kvm, cap);
+		break;
+	case KVM_CAP_ARM_RME_CREATE_RD:
+		r = kvm_create_realm(kvm);
+		break;
+	default:
+		r = -EINVAL;
+		break;
+	}
+
+	return r;
+}
+
+void kvm_destroy_realm(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+	struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
+	int i;
+
+	if (realm->params) {
+		free_page((unsigned long)realm->params);
+		realm->params = NULL;
+	}
+
+	if (!kvm_realm_is_created(kvm))
+		return;
+
+	WRITE_ONCE(realm->state, REALM_STATE_DYING);
+
+	if (realm->rd) {
+		phys_addr_t rd_phys = virt_to_phys(realm->rd);
+
+		if (WARN_ON(rmi_realm_destroy(rd_phys)))
+			return;
+		if (WARN_ON(rmi_granule_undelegate(rd_phys)))
+			return;
+		free_page((unsigned long)realm->rd);
+		realm->rd = NULL;
+	}
+
+	rme_vmid_release(realm->vmid);
+
+	for (i = 0; i < pgt->pgd_pages; i++) {
+		phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
+
+		if (WARN_ON(rmi_granule_undelegate(pgd_phys)))
+			return;
+
+		clear_page(phys_to_virt(pgd_phys));
+	}
+
+	WRITE_ONCE(realm->state, REALM_STATE_DEAD);
+
+	/* Now that the Realm is destroyed, free the entry level RTTs */
+	kvm_free_stage2_pgd(&kvm->arch.mmu);
+}
+
+int kvm_init_realm_vm(struct kvm *kvm)
+{
+	struct realm_params *params;
+
+	params = (struct realm_params *)get_zeroed_page(GFP_KERNEL);
+	if (!params)
+		return -ENOMEM;
+
+	kvm->arch.realm.params = params;
+	return 0;
+}
+
 void kvm_init_rme(void)
 {
 	if (PAGE_SIZE != SZ_4K)
@@ -46,5 +323,11 @@ void kvm_init_rme(void)
 		/* Continue without realm support */
 		return;
 
+	if (WARN_ON(rmi_features(0, &rmm_feat_reg0)))
+		return;
+
+	if (rme_vmid_init())
+		return;
+
 	/* Future patch will enable static branch kvm_rme_is_available */
 }
-- 
2.34.1

Re: [PATCH v4 09/43] arm64: RME: ioctls to create and configure realms

[Shanker Donthineni]

On 8/21/24 10:38, Steven Price wrote:
> External email: Use caution opening links or attachments
> 
> 
> Add the KVM_CAP_ARM_RME_CREATE_RD ioctl to create a realm. This involves
> delegating pages to the RMM to hold the Realm Descriptor (RD) and for
> the base level of the Realm Translation Tables (RTT). A VMID also need
> to be picked, since the RMM has a separate VMID address space a
> dedicated allocator is added for this purpose.
> 
> KVM_CAP_ARM_RME_CONFIG_REALM is provided to allow configuring the realm
> before it is created. Configuration options can be classified as:
> 
>   1. Parameters specific to the Realm stage2 (e.g. IPA Size, vmid, stage2
>      entry level, entry level RTTs, number of RTTs in start level, LPA2)
>      Most of these are not measured by RMM and comes from KVM book
>      keeping.
> 
>   2. Parameters controlling "Arm Architecture features for the VM". (e.g.
>      SVE VL, PMU counters, number of HW BRPs/WPs), configured by the VMM
>      using the "user ID register write" mechanism. These will be
>      supported in the later patches.
> 
>   3. Parameters are not part of the core Arm architecture but defined
>      by the RMM spec (e.g. Hash algorithm for measurement,
>      Personalisation value). These are programmed via
>      KVM_CAP_ARM_RME_CONFIG_REALM.
> 
> For the IPA size there is the possibility that the RMM supports a
> different size to the IPA size supported by KVM for normal guests. At
> the moment the 'normal limit' is exposed by KVM_CAP_ARM_VM_IPA_SIZE and
> the IPA size is configured by the bottom bits of vm_type in
> KVM_CREATE_VM. This means that it isn't easy for the VMM to discover
> what IPA sizes are supported for Realm guests. Since the IPA is part of
> the measurement of the realm guest the current expectation is that the
> VMM will be required to pick the IPA size demanded by attestation and
> therefore simply failing if this isn't available is fine. An option
> would be to expose a new capability ioctl to obtain the RMM's maximum
> IPA size if this is needed in the future.
> 
> Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>   * Improved commit description.
>   * Improved return failures for rmi_check_version().
>   * Clear contents of PGD after it has been undelegated in case the RMM
>     left stale data.
>   * Minor changes to reflect changes in previous patches.
> ---
>   arch/arm64/include/asm/kvm_emulate.h |   5 +
>   arch/arm64/include/asm/kvm_rme.h     |  19 ++
>   arch/arm64/kvm/arm.c                 |  18 ++
>   arch/arm64/kvm/mmu.c                 |  20 +-
>   arch/arm64/kvm/rme.c                 | 283 +++++++++++++++++++++++++++
>   5 files changed, 341 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index c7bfb6788c96..5edcfb1b6c68 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -705,6 +705,11 @@ static inline enum realm_state kvm_realm_state(struct kvm *kvm)
>          return READ_ONCE(kvm->arch.realm.state);
>   }
> 
> +static inline bool kvm_realm_is_created(struct kvm *kvm)
> +{
> +       return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
> +}
> +
>   static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>   {
>          return false;
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index 69af5c3a1e44..209cd99f03dd 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -6,6 +6,8 @@
>   #ifndef __ASM_KVM_RME_H
>   #define __ASM_KVM_RME_H
> 
> +#include <uapi/linux/kvm.h>
> +
>   /**
>    * enum realm_state - State of a Realm
>    */
> @@ -46,11 +48,28 @@ enum realm_state {
>    * struct realm - Additional per VM data for a Realm
>    *
>    * @state: The lifetime state machine for the realm
> + * @rd: Kernel mapping of the Realm Descriptor (RD)
> + * @params: Parameters for the RMI_REALM_CREATE command
> + * @num_aux: The number of auxiliary pages required by the RMM
> + * @vmid: VMID to be used by the RMM for the realm
> + * @ia_bits: Number of valid Input Address bits in the IPA
>    */
>   struct realm {
>          enum realm_state state;
> +
> +       void *rd;
> +       struct realm_params *params;
> +
> +       unsigned long num_aux;
> +       unsigned int vmid;
> +       unsigned int ia_bits;
>   };
> 
>   void kvm_init_rme(void);
> +u32 kvm_realm_ipa_limit(void);
> +
> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
> +int kvm_init_realm_vm(struct kvm *kvm);
> +void kvm_destroy_realm(struct kvm *kvm);
> 
>   #endif
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 71ffcc766eeb..15c7c2cabbf7 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -152,6 +152,13 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
>                  }
>                  mutex_unlock(&kvm->slots_lock);
>                  break;
> +       case KVM_CAP_ARM_RME:
> +               if (!kvm_is_realm(kvm))
> +                       return -EINVAL;
> +               mutex_lock(&kvm->lock);
> +               r = kvm_realm_enable_cap(kvm, cap);
> +               mutex_unlock(&kvm->lock);
> +               break;
>          default:
>                  break;
>          }
> @@ -213,6 +220,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> 
>          bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES);
> 
> +       /* Initialise the realm bits after the generic bits are enabled */
> +       if (kvm_is_realm(kvm)) {
> +               ret = kvm_init_realm_vm(kvm);
> +               if (ret)
> +                       goto err_free_cpumask;
> +       }
> +
>          return 0;
> 
>   err_free_cpumask:
> @@ -271,6 +285,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
>          kvm_unshare_hyp(kvm, kvm + 1);
> 
>          kvm_arm_teardown_hypercalls(kvm);
> +       kvm_destroy_realm(kvm);
>   }
> 
>   static bool kvm_has_full_ptr_auth(void)
> @@ -418,6 +433,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>          case KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES:
>                  r = BIT(0);
>                  break;
> +       case KVM_CAP_ARM_RME:
> +               r = static_key_enabled(&kvm_rme_is_available);
> +               break;
>          default:
>                  r = 0;
>          }
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 6981b1bc0946..2257a3b4fb06 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -862,11 +862,16 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
>          .icache_inval_pou       = invalidate_icache_guest_page,
>   };
> 
> -static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
> +static int kvm_init_ipa_range(struct kvm *kvm,
> +                             struct kvm_s2_mmu *mmu, unsigned long type)
>   {
>          u32 kvm_ipa_limit = get_kvm_ipa_limit();
>          u64 mmfr0, mmfr1;
>          u32 phys_shift;
> +       u32 ipa_limit = kvm_ipa_limit;
> +
> +       if (kvm_is_realm(kvm))
> +               ipa_limit = kvm_realm_ipa_limit();
> 
>          if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
>                  return -EINVAL;
> @@ -875,12 +880,12 @@ static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long type)
>          if (is_protected_kvm_enabled()) {
>                  phys_shift = kvm_ipa_limit;
>          } else if (phys_shift) {
> -               if (phys_shift > kvm_ipa_limit ||
> +               if (phys_shift > ipa_limit ||
>                      phys_shift < ARM64_MIN_PARANGE_BITS)
>                          return -EINVAL;
>          } else {
>                  phys_shift = KVM_PHYS_SHIFT;
> -               if (phys_shift > kvm_ipa_limit) {
> +               if (phys_shift > ipa_limit) {
>                          pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
>                                       current->comm);
>                          return -EINVAL;
> @@ -932,7 +937,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
>                  return -EINVAL;
>          }
> 
> -       err = kvm_init_ipa_range(mmu, type);
> +       err = kvm_init_ipa_range(kvm, mmu, type);
>          if (err)
>                  return err;
> 
> @@ -1055,6 +1060,13 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>          struct kvm_pgtable *pgt = NULL;
> 
>          write_lock(&kvm->mmu_lock);
> +       if (kvm_is_realm(kvm) &&
> +           (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
> +            kvm_realm_state(kvm) != REALM_STATE_NONE)) {
> +               /* Tearing down RTTs will be added in a later patch */
> +               write_unlock(&kvm->mmu_lock);
> +               return;
> +       }
>          pgt = mmu->pgt;
>          if (pgt) {
>                  mmu->pgd_phys = 0;
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> index 418685fbf6ed..4d21ec5f2910 100644
> --- a/arch/arm64/kvm/rme.c
> +++ b/arch/arm64/kvm/rme.c
> @@ -5,9 +5,20 @@
> 
>   #include <linux/kvm_host.h>
> 
> +#include <asm/kvm_emulate.h>
> +#include <asm/kvm_mmu.h>
>   #include <asm/rmi_cmds.h>
>   #include <asm/virt.h>
> 
> +#include <asm/kvm_pgtable.h>
> +
> +static unsigned long rmm_feat_reg0;
> +
> +static bool rme_supports(unsigned long feature)
> +{
> +       return !!u64_get_bits(rmm_feat_reg0, feature);
> +}
> +
>   static int rmi_check_version(void)
>   {
>          struct arm_smccc_res res;
> @@ -36,6 +47,272 @@ static int rmi_check_version(void)
>          return 0;
>   }
> 
> +u32 kvm_realm_ipa_limit(void)
> +{
> +       return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
> +}
> +
> +static int get_start_level(struct realm *realm)
> +{
> +       return 4 - stage2_pgtable_levels(realm->ia_bits);
> +}
> +
> +static int realm_create_rd(struct kvm *kvm)
> +{
> +       struct realm *realm = &kvm->arch.realm;
> +       struct realm_params *params = realm->params;
> +       void *rd = NULL;
> +       phys_addr_t rd_phys, params_phys;
> +       struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
> +       int i, r;
> +
> +       if (WARN_ON(realm->rd) || WARN_ON(!realm->params))
> +               return -EEXIST;
> +
> +       rd = (void *)__get_free_page(GFP_KERNEL);
> +       if (!rd)
> +               return -ENOMEM;
> +
> +       rd_phys = virt_to_phys(rd);
> +       if (rmi_granule_delegate(rd_phys)) {
> +               r = -ENXIO;
> +               goto free_rd;
> +       }
> +
> +       for (i = 0; i < pgt->pgd_pages; i++) {
> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
> +
> +               if (rmi_granule_delegate(pgd_phys)) {
> +                       r = -ENXIO;
> +                       goto out_undelegate_tables;
> +               }
> +       }
> +
> +       realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
> +
> +       params->s2sz = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
> +       params->rtt_level_start = get_start_level(realm);
> +       params->rtt_num_start = pgt->pgd_pages;
> +       params->rtt_base = kvm->arch.mmu.pgd_phys;
> +       params->vmid = realm->vmid;
> +
> +       params_phys = virt_to_phys(params);
> +
> +       if (rmi_realm_create(rd_phys, params_phys)) {
> +               r = -ENXIO;
> +               goto out_undelegate_tables;
> +       }
> +
> +       realm->rd = rd;
> +
> +       if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
> +               WARN_ON(rmi_realm_destroy(rd_phys));
> +               goto out_undelegate_tables;
> +       }
> +
> +       return 0;
> +
> +out_undelegate_tables:
> +       while (--i >= 0) {
> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
> +
> +               WARN_ON(rmi_granule_undelegate(pgd_phys));
> +       }
> +       WARN_ON(rmi_granule_undelegate(rd_phys));
> +free_rd:
> +       free_page((unsigned long)rd);
> +       return r;
> +}
> +
> +/* Protects access to rme_vmid_bitmap */
> +static DEFINE_SPINLOCK(rme_vmid_lock);
> +static unsigned long *rme_vmid_bitmap;
> +
> +static int rme_vmid_init(void)
> +{
> +       unsigned int vmid_count = 1 << kvm_get_vmid_bits();
> +
> +       rme_vmid_bitmap = bitmap_zalloc(vmid_count, GFP_KERNEL);
> +       if (!rme_vmid_bitmap) {
> +               kvm_err("%s: Couldn't allocate rme vmid bitmap\n", __func__);
> +               return -ENOMEM;
> +       }
> +
> +       return 0;
> +}
> +
> +static int rme_vmid_reserve(void)
> +{
> +       int ret;
> +       unsigned int vmid_count = 1 << kvm_get_vmid_bits();
> +
> +       spin_lock(&rme_vmid_lock);
> +       ret = bitmap_find_free_region(rme_vmid_bitmap, vmid_count, 0);
> +       spin_unlock(&rme_vmid_lock);
> +
> +       return ret;
> +}
> +
> +static void rme_vmid_release(unsigned int vmid)
> +{
> +       spin_lock(&rme_vmid_lock);
> +       bitmap_release_region(rme_vmid_bitmap, vmid, 0);
> +       spin_unlock(&rme_vmid_lock);
> +}
> +
> +static int kvm_create_realm(struct kvm *kvm)
> +{
> +       struct realm *realm = &kvm->arch.realm;
> +       int ret;
> +
> +       if (!kvm_is_realm(kvm))
> +               return -EINVAL;
> +       if (kvm_realm_is_created(kvm))
> +               return -EEXIST;
> +
> +       ret = rme_vmid_reserve();
> +       if (ret < 0)
> +               return ret;
> +       realm->vmid = ret;
> +
> +       ret = realm_create_rd(kvm);
> +       if (ret) {
> +               rme_vmid_release(realm->vmid);
> +               return ret;
> +       }
> +
> +       WRITE_ONCE(realm->state, REALM_STATE_NEW);
> +
> +       /* The realm is up, free the parameters.  */
> +       free_page((unsigned long)realm->params);
> +       realm->params = NULL;
Is there a specific reason for freeing the params? The pointer is
referenced in rtt_get_phys() without a NULL check, which leads to
a kernel crash.

static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
{
         bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;

> +
> +       return 0;
> +}
> +
> +static int config_realm_hash_algo(struct realm *realm,
> +                                 struct kvm_cap_arm_rme_config_item *cfg)
> +{
> +       switch (cfg->hash_algo) {
> +       case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA256:
> +               if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_256))
> +                       return -EINVAL;
> +               break;
> +       case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA512:
> +               if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_512))
> +                       return -EINVAL;
> +               break;
> +       default:
> +               return -EINVAL;
> +       }
> +       realm->params->hash_algo = cfg->hash_algo;
> +       return 0;
> +}
> +
> +static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap)
> +{
> +       struct kvm_cap_arm_rme_config_item cfg;
> +       struct realm *realm = &kvm->arch.realm;
> +       int r = 0;
> +
> +       if (kvm_realm_is_created(kvm))
> +               return -EBUSY;
> +
> +       if (copy_from_user(&cfg, (void __user *)cap->args[1], sizeof(cfg)))
> +               return -EFAULT;
> +
> +       switch (cfg.cfg) {
> +       case KVM_CAP_ARM_RME_CFG_RPV:
> +               memcpy(&realm->params->rpv, &cfg.rpv, sizeof(cfg.rpv));
> +               break;
> +       case KVM_CAP_ARM_RME_CFG_HASH_ALGO:
> +               r = config_realm_hash_algo(realm, &cfg);
> +               break;
> +       default:
> +               r = -EINVAL;
> +       }
> +
> +       return r;
> +}
> +
> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
> +{
> +       int r = 0;
> +
> +       if (!kvm_is_realm(kvm))
> +               return -EINVAL;
> +
> +       switch (cap->args[0]) {
> +       case KVM_CAP_ARM_RME_CONFIG_REALM:
> +               r = kvm_rme_config_realm(kvm, cap);
> +               break;
> +       case KVM_CAP_ARM_RME_CREATE_RD:
> +               r = kvm_create_realm(kvm);
> +               break;
> +       default:
> +               r = -EINVAL;
> +               break;
> +       }
> +
> +       return r;
> +}
> +
> +void kvm_destroy_realm(struct kvm *kvm)
> +{
> +       struct realm *realm = &kvm->arch.realm;
> +       struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
> +       int i;
> +
> +       if (realm->params) {
> +               free_page((unsigned long)realm->params);
> +               realm->params = NULL;
> +       }
> +
> +       if (!kvm_realm_is_created(kvm))
> +               return;
> +
> +       WRITE_ONCE(realm->state, REALM_STATE_DYING);
> +
> +       if (realm->rd) {
> +               phys_addr_t rd_phys = virt_to_phys(realm->rd);
> +
> +               if (WARN_ON(rmi_realm_destroy(rd_phys)))
> +                       return;
> +               if (WARN_ON(rmi_granule_undelegate(rd_phys)))
> +                       return;
> +               free_page((unsigned long)realm->rd);
> +               realm->rd = NULL;
> +       }
> +
> +       rme_vmid_release(realm->vmid);
> +
> +       for (i = 0; i < pgt->pgd_pages; i++) {
> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
> +
> +               if (WARN_ON(rmi_granule_undelegate(pgd_phys)))
> +                       return;
> +
> +               clear_page(phys_to_virt(pgd_phys));
> +       }
> +
> +       WRITE_ONCE(realm->state, REALM_STATE_DEAD);
> +
> +       /* Now that the Realm is destroyed, free the entry level RTTs */
> +       kvm_free_stage2_pgd(&kvm->arch.mmu);
> +}
> +
> +int kvm_init_realm_vm(struct kvm *kvm)
> +{
> +       struct realm_params *params;
> +
> +       params = (struct realm_params *)get_zeroed_page(GFP_KERNEL);
> +       if (!params)
> +               return -ENOMEM;
> +
> +       kvm->arch.realm.params = params;
> +       return 0;
> +}
> +
>   void kvm_init_rme(void)
>   {
>          if (PAGE_SIZE != SZ_4K)
> @@ -46,5 +323,11 @@ void kvm_init_rme(void)
>                  /* Continue without realm support */
>                  return;
> 
> +       if (WARN_ON(rmi_features(0, &rmm_feat_reg0)))
> +               return;
> +
> +       if (rme_vmid_init())
> +               return;
> +
>          /* Future patch will enable static branch kvm_rme_is_available */
>   }
> --
> 2.34.1
> 

Re: [PATCH v4 09/43] arm64: RME: ioctls to create and configure realms

[Suzuki K Poulose]

On 06/09/2024 20:05, Shanker Donthineni wrote:
> 
> 
> On 8/21/24 10:38, Steven Price wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> Add the KVM_CAP_ARM_RME_CREATE_RD ioctl to create a realm. This involves
>> delegating pages to the RMM to hold the Realm Descriptor (RD) and for
>> the base level of the Realm Translation Tables (RTT). A VMID also need
>> to be picked, since the RMM has a separate VMID address space a
>> dedicated allocator is added for this purpose.
>>
>> KVM_CAP_ARM_RME_CONFIG_REALM is provided to allow configuring the realm
>> before it is created. Configuration options can be classified as:
>>
>>   1. Parameters specific to the Realm stage2 (e.g. IPA Size, vmid, stage2
>>      entry level, entry level RTTs, number of RTTs in start level, LPA2)
>>      Most of these are not measured by RMM and comes from KVM book
>>      keeping.
>>
>>   2. Parameters controlling "Arm Architecture features for the VM". (e.g.
>>      SVE VL, PMU counters, number of HW BRPs/WPs), configured by the VMM
>>      using the "user ID register write" mechanism. These will be
>>      supported in the later patches.
>>
>>   3. Parameters are not part of the core Arm architecture but defined
>>      by the RMM spec (e.g. Hash algorithm for measurement,
>>      Personalisation value). These are programmed via
>>      KVM_CAP_ARM_RME_CONFIG_REALM.
>>
>> For the IPA size there is the possibility that the RMM supports a
>> different size to the IPA size supported by KVM for normal guests. At
>> the moment the 'normal limit' is exposed by KVM_CAP_ARM_VM_IPA_SIZE and
>> the IPA size is configured by the bottom bits of vm_type in
>> KVM_CREATE_VM. This means that it isn't easy for the VMM to discover
>> what IPA sizes are supported for Realm guests. Since the IPA is part of
>> the measurement of the realm guest the current expectation is that the
>> VMM will be required to pick the IPA size demanded by attestation and
>> therefore simply failing if this isn't available is fine. An option
>> would be to expose a new capability ioctl to obtain the RMM's maximum
>> IPA size if this is needed in the future.
>>
>> Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>   * Improved commit description.
>>   * Improved return failures for rmi_check_version().
>>   * Clear contents of PGD after it has been undelegated in case the RMM
>>     left stale data.
>>   * Minor changes to reflect changes in previous patches.
>> ---
>>   arch/arm64/include/asm/kvm_emulate.h |   5 +
>>   arch/arm64/include/asm/kvm_rme.h     |  19 ++
>>   arch/arm64/kvm/arm.c                 |  18 ++
>>   arch/arm64/kvm/mmu.c                 |  20 +-
>>   arch/arm64/kvm/rme.c                 | 283 +++++++++++++++++++++++++++
>>   5 files changed, 341 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/kvm_emulate.h 
>> b/arch/arm64/include/asm/kvm_emulate.h
>> index c7bfb6788c96..5edcfb1b6c68 100644
>> --- a/arch/arm64/include/asm/kvm_emulate.h
>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>> @@ -705,6 +705,11 @@ static inline enum realm_state 
>> kvm_realm_state(struct kvm *kvm)
>>          return READ_ONCE(kvm->arch.realm.state);
>>   }
>>
>> +static inline bool kvm_realm_is_created(struct kvm *kvm)
>> +{
>> +       return kvm_is_realm(kvm) && kvm_realm_state(kvm) != 
>> REALM_STATE_NONE;
>> +}
>> +
>>   static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>>   {
>>          return false;
>> diff --git a/arch/arm64/include/asm/kvm_rme.h 
>> b/arch/arm64/include/asm/kvm_rme.h
>> index 69af5c3a1e44..209cd99f03dd 100644
>> --- a/arch/arm64/include/asm/kvm_rme.h
>> +++ b/arch/arm64/include/asm/kvm_rme.h
>> @@ -6,6 +6,8 @@
>>   #ifndef __ASM_KVM_RME_H
>>   #define __ASM_KVM_RME_H
>>
>> +#include <uapi/linux/kvm.h>
>> +
>>   /**
>>    * enum realm_state - State of a Realm
>>    */
>> @@ -46,11 +48,28 @@ enum realm_state {
>>    * struct realm - Additional per VM data for a Realm
>>    *
>>    * @state: The lifetime state machine for the realm
>> + * @rd: Kernel mapping of the Realm Descriptor (RD)
>> + * @params: Parameters for the RMI_REALM_CREATE command
>> + * @num_aux: The number of auxiliary pages required by the RMM
>> + * @vmid: VMID to be used by the RMM for the realm
>> + * @ia_bits: Number of valid Input Address bits in the IPA
>>    */
>>   struct realm {
>>          enum realm_state state;
>> +
>> +       void *rd;
>> +       struct realm_params *params;
>> +
>> +       unsigned long num_aux;
>> +       unsigned int vmid;
>> +       unsigned int ia_bits;
>>   };
>>
>>   void kvm_init_rme(void);
>> +u32 kvm_realm_ipa_limit(void);
>> +
>> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
>> +int kvm_init_realm_vm(struct kvm *kvm);
>> +void kvm_destroy_realm(struct kvm *kvm);
>>
>>   #endif
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 71ffcc766eeb..15c7c2cabbf7 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -152,6 +152,13 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
>>                  }
>>                  mutex_unlock(&kvm->slots_lock);
>>                  break;
>> +       case KVM_CAP_ARM_RME:
>> +               if (!kvm_is_realm(kvm))
>> +                       return -EINVAL;
>> +               mutex_lock(&kvm->lock);
>> +               r = kvm_realm_enable_cap(kvm, cap);
>> +               mutex_unlock(&kvm->lock);
>> +               break;
>>          default:
>>                  break;
>>          }
>> @@ -213,6 +220,13 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned 
>> long type)
>>
>>          bitmap_zero(kvm->arch.vcpu_features, KVM_VCPU_MAX_FEATURES);
>>
>> +       /* Initialise the realm bits after the generic bits are 
>> enabled */
>> +       if (kvm_is_realm(kvm)) {
>> +               ret = kvm_init_realm_vm(kvm);
>> +               if (ret)
>> +                       goto err_free_cpumask;
>> +       }
>> +
>>          return 0;
>>
>>   err_free_cpumask:
>> @@ -271,6 +285,7 @@ void kvm_arch_destroy_vm(struct kvm *kvm)
>>          kvm_unshare_hyp(kvm, kvm + 1);
>>
>>          kvm_arm_teardown_hypercalls(kvm);
>> +       kvm_destroy_realm(kvm);
>>   }
>>
>>   static bool kvm_has_full_ptr_auth(void)
>> @@ -418,6 +433,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, 
>> long ext)
>>          case KVM_CAP_ARM_SUPPORTED_REG_MASK_RANGES:
>>                  r = BIT(0);
>>                  break;
>> +       case KVM_CAP_ARM_RME:
>> +               r = static_key_enabled(&kvm_rme_is_available);
>> +               break;
>>          default:
>>                  r = 0;
>>          }
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 6981b1bc0946..2257a3b4fb06 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -862,11 +862,16 @@ static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
>>          .icache_inval_pou       = invalidate_icache_guest_page,
>>   };
>>
>> -static int kvm_init_ipa_range(struct kvm_s2_mmu *mmu, unsigned long 
>> type)
>> +static int kvm_init_ipa_range(struct kvm *kvm,
>> +                             struct kvm_s2_mmu *mmu, unsigned long type)
>>   {
>>          u32 kvm_ipa_limit = get_kvm_ipa_limit();
>>          u64 mmfr0, mmfr1;
>>          u32 phys_shift;
>> +       u32 ipa_limit = kvm_ipa_limit;
>> +
>> +       if (kvm_is_realm(kvm))
>> +               ipa_limit = kvm_realm_ipa_limit();
>>
>>          if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
>>                  return -EINVAL;
>> @@ -875,12 +880,12 @@ static int kvm_init_ipa_range(struct kvm_s2_mmu 
>> *mmu, unsigned long type)
>>          if (is_protected_kvm_enabled()) {
>>                  phys_shift = kvm_ipa_limit;
>>          } else if (phys_shift) {
>> -               if (phys_shift > kvm_ipa_limit ||
>> +               if (phys_shift > ipa_limit ||
>>                      phys_shift < ARM64_MIN_PARANGE_BITS)
>>                          return -EINVAL;
>>          } else {
>>                  phys_shift = KVM_PHYS_SHIFT;
>> -               if (phys_shift > kvm_ipa_limit) {
>> +               if (phys_shift > ipa_limit) {
>>                          pr_warn_once("%s using unsupported default 
>> IPA limit, upgrade your VMM\n",
>>                                       current->comm);
>>                          return -EINVAL;
>> @@ -932,7 +937,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct 
>> kvm_s2_mmu *mmu, unsigned long t
>>                  return -EINVAL;
>>          }
>>
>> -       err = kvm_init_ipa_range(mmu, type);
>> +       err = kvm_init_ipa_range(kvm, mmu, type);
>>          if (err)
>>                  return err;
>>
>> @@ -1055,6 +1060,13 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>>          struct kvm_pgtable *pgt = NULL;
>>
>>          write_lock(&kvm->mmu_lock);
>> +       if (kvm_is_realm(kvm) &&
>> +           (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
>> +            kvm_realm_state(kvm) != REALM_STATE_NONE)) {
>> +               /* Tearing down RTTs will be added in a later patch */
>> +               write_unlock(&kvm->mmu_lock);
>> +               return;
>> +       }
>>          pgt = mmu->pgt;
>>          if (pgt) {
>>                  mmu->pgd_phys = 0;
>> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
>> index 418685fbf6ed..4d21ec5f2910 100644
>> --- a/arch/arm64/kvm/rme.c
>> +++ b/arch/arm64/kvm/rme.c
>> @@ -5,9 +5,20 @@
>>
>>   #include <linux/kvm_host.h>
>>
>> +#include <asm/kvm_emulate.h>
>> +#include <asm/kvm_mmu.h>
>>   #include <asm/rmi_cmds.h>
>>   #include <asm/virt.h>
>>
>> +#include <asm/kvm_pgtable.h>
>> +
>> +static unsigned long rmm_feat_reg0;
>> +
>> +static bool rme_supports(unsigned long feature)
>> +{
>> +       return !!u64_get_bits(rmm_feat_reg0, feature);
>> +}
>> +
>>   static int rmi_check_version(void)
>>   {
>>          struct arm_smccc_res res;
>> @@ -36,6 +47,272 @@ static int rmi_check_version(void)
>>          return 0;
>>   }
>>
>> +u32 kvm_realm_ipa_limit(void)
>> +{
>> +       return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
>> +}
>> +
>> +static int get_start_level(struct realm *realm)
>> +{
>> +       return 4 - stage2_pgtable_levels(realm->ia_bits);
>> +}
>> +
>> +static int realm_create_rd(struct kvm *kvm)
>> +{
>> +       struct realm *realm = &kvm->arch.realm;
>> +       struct realm_params *params = realm->params;
>> +       void *rd = NULL;
>> +       phys_addr_t rd_phys, params_phys;
>> +       struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
>> +       int i, r;
>> +
>> +       if (WARN_ON(realm->rd) || WARN_ON(!realm->params))
>> +               return -EEXIST;
>> +
>> +       rd = (void *)__get_free_page(GFP_KERNEL);
>> +       if (!rd)
>> +               return -ENOMEM;
>> +
>> +       rd_phys = virt_to_phys(rd);
>> +       if (rmi_granule_delegate(rd_phys)) {
>> +               r = -ENXIO;
>> +               goto free_rd;
>> +       }
>> +
>> +       for (i = 0; i < pgt->pgd_pages; i++) {
>> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * 
>> PAGE_SIZE;
>> +
>> +               if (rmi_granule_delegate(pgd_phys)) {
>> +                       r = -ENXIO;
>> +                       goto out_undelegate_tables;
>> +               }
>> +       }
>> +
>> +       realm->ia_bits = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
>> +
>> +       params->s2sz = VTCR_EL2_IPA(kvm->arch.mmu.vtcr);
>> +       params->rtt_level_start = get_start_level(realm);
>> +       params->rtt_num_start = pgt->pgd_pages;
>> +       params->rtt_base = kvm->arch.mmu.pgd_phys;
>> +       params->vmid = realm->vmid;
>> +
>> +       params_phys = virt_to_phys(params);
>> +
>> +       if (rmi_realm_create(rd_phys, params_phys)) {
>> +               r = -ENXIO;
>> +               goto out_undelegate_tables;
>> +       }
>> +
>> +       realm->rd = rd;
>> +
>> +       if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
>> +               WARN_ON(rmi_realm_destroy(rd_phys));
>> +               goto out_undelegate_tables;
>> +       }
>> +
>> +       return 0;
>> +
>> +out_undelegate_tables:
>> +       while (--i >= 0) {
>> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * 
>> PAGE_SIZE;
>> +
>> +               WARN_ON(rmi_granule_undelegate(pgd_phys));
>> +       }
>> +       WARN_ON(rmi_granule_undelegate(rd_phys));
>> +free_rd:
>> +       free_page((unsigned long)rd);
>> +       return r;
>> +}
>> +
>> +/* Protects access to rme_vmid_bitmap */
>> +static DEFINE_SPINLOCK(rme_vmid_lock);
>> +static unsigned long *rme_vmid_bitmap;
>> +
>> +static int rme_vmid_init(void)
>> +{
>> +       unsigned int vmid_count = 1 << kvm_get_vmid_bits();
>> +
>> +       rme_vmid_bitmap = bitmap_zalloc(vmid_count, GFP_KERNEL);
>> +       if (!rme_vmid_bitmap) {
>> +               kvm_err("%s: Couldn't allocate rme vmid bitmap\n", 
>> __func__);
>> +               return -ENOMEM;
>> +       }
>> +
>> +       return 0;
>> +}
>> +
>> +static int rme_vmid_reserve(void)
>> +{
>> +       int ret;
>> +       unsigned int vmid_count = 1 << kvm_get_vmid_bits();
>> +
>> +       spin_lock(&rme_vmid_lock);
>> +       ret = bitmap_find_free_region(rme_vmid_bitmap, vmid_count, 0);
>> +       spin_unlock(&rme_vmid_lock);
>> +
>> +       return ret;
>> +}
>> +
>> +static void rme_vmid_release(unsigned int vmid)
>> +{
>> +       spin_lock(&rme_vmid_lock);
>> +       bitmap_release_region(rme_vmid_bitmap, vmid, 0);
>> +       spin_unlock(&rme_vmid_lock);
>> +}
>> +
>> +static int kvm_create_realm(struct kvm *kvm)
>> +{
>> +       struct realm *realm = &kvm->arch.realm;
>> +       int ret;
>> +
>> +       if (!kvm_is_realm(kvm))
>> +               return -EINVAL;
>> +       if (kvm_realm_is_created(kvm))
>> +               return -EEXIST;
>> +
>> +       ret = rme_vmid_reserve();
>> +       if (ret < 0)
>> +               return ret;
>> +       realm->vmid = ret;
>> +
>> +       ret = realm_create_rd(kvm);
>> +       if (ret) {
>> +               rme_vmid_release(realm->vmid);
>> +               return ret;
>> +       }
>> +
>> +       WRITE_ONCE(realm->state, REALM_STATE_NEW);
>> +
>> +       /* The realm is up, free the parameters.  */
>> +       free_page((unsigned long)realm->params);
>> +       realm->params = NULL;
> Is there a specific reason for freeing the params? The pointer is
> referenced in rtt_get_phys() without a NULL check, which leads to
> a kernel crash.
> 
> static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
> {
>          bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;
> 

Good catch. The params is a full PAGE (4K) which is passed on to the RMM
for initial parameters and we don't need as much space to keep track of
the realm attributes. Hence we free it after the use.

The LPA2 flag could be cached in the struct realm instead.

Suzuki


>> +
>> +       return 0;
>> +}
>> +
>> +static int config_realm_hash_algo(struct realm *realm,
>> +                                 struct kvm_cap_arm_rme_config_item 
>> *cfg)
>> +{
>> +       switch (cfg->hash_algo) {
>> +       case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA256:
>> +               if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_256))
>> +                       return -EINVAL;
>> +               break;
>> +       case KVM_CAP_ARM_RME_MEASUREMENT_ALGO_SHA512:
>> +               if (!rme_supports(RMI_FEATURE_REGISTER_0_HASH_SHA_512))
>> +                       return -EINVAL;
>> +               break;
>> +       default:
>> +               return -EINVAL;
>> +       }
>> +       realm->params->hash_algo = cfg->hash_algo;
>> +       return 0;
>> +}
>> +
>> +static int kvm_rme_config_realm(struct kvm *kvm, struct 
>> kvm_enable_cap *cap)
>> +{
>> +       struct kvm_cap_arm_rme_config_item cfg;
>> +       struct realm *realm = &kvm->arch.realm;
>> +       int r = 0;
>> +
>> +       if (kvm_realm_is_created(kvm))
>> +               return -EBUSY;
>> +
>> +       if (copy_from_user(&cfg, (void __user *)cap->args[1], 
>> sizeof(cfg)))
>> +               return -EFAULT;
>> +
>> +       switch (cfg.cfg) {
>> +       case KVM_CAP_ARM_RME_CFG_RPV:
>> +               memcpy(&realm->params->rpv, &cfg.rpv, sizeof(cfg.rpv));
>> +               break;
>> +       case KVM_CAP_ARM_RME_CFG_HASH_ALGO:
>> +               r = config_realm_hash_algo(realm, &cfg);
>> +               break;
>> +       default:
>> +               r = -EINVAL;
>> +       }
>> +
>> +       return r;
>> +}
>> +
>> +int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
>> +{
>> +       int r = 0;
>> +
>> +       if (!kvm_is_realm(kvm))
>> +               return -EINVAL;
>> +
>> +       switch (cap->args[0]) {
>> +       case KVM_CAP_ARM_RME_CONFIG_REALM:
>> +               r = kvm_rme_config_realm(kvm, cap);
>> +               break;
>> +       case KVM_CAP_ARM_RME_CREATE_RD:
>> +               r = kvm_create_realm(kvm);
>> +               break;
>> +       default:
>> +               r = -EINVAL;
>> +               break;
>> +       }
>> +
>> +       return r;
>> +}
>> +
>> +void kvm_destroy_realm(struct kvm *kvm)
>> +{
>> +       struct realm *realm = &kvm->arch.realm;
>> +       struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
>> +       int i;
>> +
>> +       if (realm->params) {
>> +               free_page((unsigned long)realm->params);
>> +               realm->params = NULL;
>> +       }
>> +
>> +       if (!kvm_realm_is_created(kvm))
>> +               return;
>> +
>> +       WRITE_ONCE(realm->state, REALM_STATE_DYING);
>> +
>> +       if (realm->rd) {
>> +               phys_addr_t rd_phys = virt_to_phys(realm->rd);
>> +
>> +               if (WARN_ON(rmi_realm_destroy(rd_phys)))
>> +                       return;
>> +               if (WARN_ON(rmi_granule_undelegate(rd_phys)))
>> +                       return;
>> +               free_page((unsigned long)realm->rd);
>> +               realm->rd = NULL;
>> +       }
>> +
>> +       rme_vmid_release(realm->vmid);
>> +
>> +       for (i = 0; i < pgt->pgd_pages; i++) {
>> +               phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * 
>> PAGE_SIZE;
>> +
>> +               if (WARN_ON(rmi_granule_undelegate(pgd_phys)))
>> +                       return;
>> +
>> +               clear_page(phys_to_virt(pgd_phys));
>> +       }
>> +
>> +       WRITE_ONCE(realm->state, REALM_STATE_DEAD);
>> +
>> +       /* Now that the Realm is destroyed, free the entry level RTTs */
>> +       kvm_free_stage2_pgd(&kvm->arch.mmu);
>> +}
>> +
>> +int kvm_init_realm_vm(struct kvm *kvm)
>> +{
>> +       struct realm_params *params;
>> +
>> +       params = (struct realm_params *)get_zeroed_page(GFP_KERNEL);
>> +       if (!params)
>> +               return -ENOMEM;
>> +
>> +       kvm->arch.realm.params = params;
>> +       return 0;
>> +}
>> +
>>   void kvm_init_rme(void)
>>   {
>>          if (PAGE_SIZE != SZ_4K)
>> @@ -46,5 +323,11 @@ void kvm_init_rme(void)
>>                  /* Continue without realm support */
>>                  return;
>>
>> +       if (WARN_ON(rmi_features(0, &rmm_feat_reg0)))
>> +               return;
>> +
>> +       if (rme_vmid_init())
>> +               return;
>> +
>>          /* Future patch will enable static branch 
>> kvm_rme_is_available */
>>   }
>> -- 
>> 2.34.1
>>
> 

[PATCH v4 10/43] kvm: arm64: Expose debug HW register numbers for Realm

[Steven Price]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

Expose VM specific Debug HW register numbers.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 15c7c2cabbf7..6f3b2c907c85 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -77,6 +77,22 @@ bool is_kvm_arm_initialised(void)
 	return kvm_arm_initialised;
 }
 
+static u32 kvm_arm_get_num_brps(struct kvm *kvm)
+{
+	if (!kvm_is_realm(kvm))
+		return get_num_brps();
+	/* Realm guest is not debuggable. */
+	return 0;
+}
+
+static u32 kvm_arm_get_num_wrps(struct kvm *kvm)
+{
+	if (!kvm_is_realm(kvm))
+		return get_num_wrps();
+	/* Realm guest is not debuggable. */
+	return 0;
+}
+
 int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu)
 {
 	return kvm_vcpu_exiting_guest_mode(vcpu) == IN_GUEST_MODE;
@@ -347,7 +363,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ARM_IRQ_LINE_LAYOUT_2:
 	case KVM_CAP_ARM_NISV_TO_USER:
 	case KVM_CAP_ARM_INJECT_EXT_DABT:
-	case KVM_CAP_SET_GUEST_DEBUG:
 	case KVM_CAP_VCPU_ATTRIBUTES:
 	case KVM_CAP_PTP_KVM:
 	case KVM_CAP_ARM_SYSTEM_SUSPEND:
@@ -355,6 +370,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_COUNTER_OFFSET:
 		r = 1;
 		break;
+	case KVM_CAP_SET_GUEST_DEBUG:
+		r = !kvm_is_realm(kvm);
+		break;
 	case KVM_CAP_SET_GUEST_DEBUG2:
 		return KVM_GUESTDBG_VALID_MASK;
 	case KVM_CAP_ARM_SET_DEVICE_ADDR:
@@ -400,10 +418,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = cpus_have_final_cap(ARM64_HAS_32BIT_EL1);
 		break;
 	case KVM_CAP_GUEST_DEBUG_HW_BPS:
-		r = get_num_brps();
+		r = kvm_arm_get_num_brps(kvm);
 		break;
 	case KVM_CAP_GUEST_DEBUG_HW_WPS:
-		r = get_num_wrps();
+		r = kvm_arm_get_num_wrps(kvm);
 		break;
 	case KVM_CAP_ARM_PMU_V3:
 		r = kvm_arm_support_pmu_v3();
-- 
2.34.1

[PATCH v4 11/43] arm64: kvm: Allow passing machine type in KVM creation

[Steven Price]

Previously machine type was used purely for specifying the physical
address size of the guest. Reserve the higher bits to specify an ARM
specific machine type and declare a new type 'KVM_VM_TYPE_ARM_REALM'
used to create a realm guest.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c     | 17 +++++++++++++++++
 arch/arm64/kvm/mmu.c     |  3 ---
 include/uapi/linux/kvm.h | 19 +++++++++++++++----
 3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 6f3b2c907c85..fb1ed1f44561 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -205,6 +205,23 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	mutex_unlock(&kvm->lock);
 #endif
 
+	if (type & ~(KVM_VM_TYPE_ARM_MASK | KVM_VM_TYPE_ARM_IPA_SIZE_MASK))
+		return -EINVAL;
+
+	switch (type & KVM_VM_TYPE_ARM_MASK) {
+	case KVM_VM_TYPE_ARM_NORMAL:
+		break;
+	case KVM_VM_TYPE_ARM_REALM:
+		kvm->arch.is_realm = true;
+		if (!kvm_is_realm(kvm)) {
+			/* Realm support unavailable */
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
 	kvm_init_nested(kvm);
 
 	ret = kvm_share_hyp(kvm, kvm + 1);
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 2257a3b4fb06..4e6a1e39ceb3 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -873,9 +873,6 @@ static int kvm_init_ipa_range(struct kvm *kvm,
 	if (kvm_is_realm(kvm))
 		ipa_limit = kvm_realm_ipa_limit();
 
-	if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
-		return -EINVAL;
-
 	phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
 	if (is_protected_kvm_enabled()) {
 		phys_shift = kvm_ipa_limit;
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index b3884757739d..74f256eb07d2 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -648,14 +648,25 @@ struct kvm_enable_cap {
 #define KVM_S390_SIE_PAGE_OFFSET 1
 
 /*
- * On arm64, machine type can be used to request the physical
- * address size for the VM. Bits[7-0] are reserved for the guest
- * PA size shift (i.e, log2(PA_Size)). For backward compatibility,
- * value 0 implies the default IPA size, 40bits.
+ * On arm64, machine type can be used to request both the machine type and
+ * the physical address size for the VM.
+ *
+ * Bits[11-8] are reserved for the ARM specific machine type.
+ *
+ * Bits[7-0] are reserved for the guest PA size shift (i.e, log2(PA_Size)).
+ * For backward compatibility, value 0 implies the default IPA size, 40bits.
  */
+#define KVM_VM_TYPE_ARM_SHIFT		8
+#define KVM_VM_TYPE_ARM_MASK		(0xfULL << KVM_VM_TYPE_ARM_SHIFT)
+#define KVM_VM_TYPE_ARM(_type)		\
+	(((_type) << KVM_VM_TYPE_ARM_SHIFT) & KVM_VM_TYPE_ARM_MASK)
+#define KVM_VM_TYPE_ARM_NORMAL		KVM_VM_TYPE_ARM(0)
+#define KVM_VM_TYPE_ARM_REALM		KVM_VM_TYPE_ARM(1)
+
 #define KVM_VM_TYPE_ARM_IPA_SIZE_MASK	0xffULL
 #define KVM_VM_TYPE_ARM_IPA_SIZE(x)		\
 	((x) & KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
+
 /*
  * ioctls for /dev/kvm fds:
  */
-- 
2.34.1

[PATCH v4 12/43] arm64: RME: Keep a spare page delegated to the RMM

[Steven Price]

Pages can only be populated/destroyed on the RMM at the 4KB granule,
this requires creating the full depth of RTTs. However if the pages are
going to be combined into a 2MB huge page the last RTT is only
temporarily needed. Similarly when freeing memory the huge page must be
temporarily split requiring temporary usage of the full depth oF RTTs.

To avoid needing to perform a temporary allocation and delegation of a
page for this purpose we keep a spare delegated page around. In
particular this avoids the need for memory allocation while destroying
the realm guest.

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h | 5 +++++
 arch/arm64/kvm/rme.c             | 8 ++++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 209cd99f03dd..bd306bd7b64b 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -50,6 +50,9 @@ enum realm_state {
  * @state: The lifetime state machine for the realm
  * @rd: Kernel mapping of the Realm Descriptor (RD)
  * @params: Parameters for the RMI_REALM_CREATE command
+ * @spare_page: A physical page that has been delegated to the Realm world but
+ *              is otherwise free. Used to avoid temporary allocation during
+ *              RTT operations.
  * @num_aux: The number of auxiliary pages required by the RMM
  * @vmid: VMID to be used by the RMM for the realm
  * @ia_bits: Number of valid Input Address bits in the IPA
@@ -60,6 +63,8 @@ struct realm {
 	void *rd;
 	struct realm_params *params;
 
+	phys_addr_t spare_page;
+
 	unsigned long num_aux;
 	unsigned int vmid;
 	unsigned int ia_bits;
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 4d21ec5f2910..f6430d460519 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -104,6 +104,7 @@ static int realm_create_rd(struct kvm *kvm)
 	}
 
 	realm->rd = rd;
+	realm->spare_page = PHYS_ADDR_MAX;
 
 	if (WARN_ON(rmi_rec_aux_count(rd_phys, &realm->num_aux))) {
 		WARN_ON(rmi_realm_destroy(rd_phys));
@@ -286,6 +287,13 @@ void kvm_destroy_realm(struct kvm *kvm)
 
 	rme_vmid_release(realm->vmid);
 
+	if (realm->spare_page != PHYS_ADDR_MAX) {
+		/* Leak the page if the undelegate fails */
+		if (!WARN_ON(rmi_granule_undelegate(realm->spare_page)))
+			free_page((unsigned long)phys_to_virt(realm->spare_page));
+		realm->spare_page = PHYS_ADDR_MAX;
+	}
+
 	for (i = 0; i < pgt->pgd_pages; i++) {
 		phys_addr_t pgd_phys = kvm->arch.mmu.pgd_phys + i * PAGE_SIZE;
 
-- 
2.34.1

[PATCH v4 13/43] arm64: RME: RTT tear down

[Steven Price]

The RMM owns the stage 2 page tables for a realm, and KVM must request
that the RMM creates/destroys entries as necessary. The physical pages
to store the page tables are delegated to the realm as required, and can
be undelegated when no longer used.

Creating new RTTs is the easy part, tearing down is a little more
tricky. The result of realm_rtt_destroy() can be used to effectively
walk the tree and destroy the entries (undelegating pages that were
given to the realm).

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Moved {alloc,free}_delegated_page() and ensure_spare_page() to a
   later patch when they are actually used.
 * Some simplifications now rmi_xxx() functions allow NULL as an output
   parameter.
 * Improved comments and code layout.
---
 arch/arm64/include/asm/kvm_rme.h |  19 ++++++
 arch/arm64/kvm/mmu.c             |   6 +-
 arch/arm64/kvm/rme.c             | 113 +++++++++++++++++++++++++++++++
 3 files changed, 135 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index bd306bd7b64b..e5704859a6e5 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -76,5 +76,24 @@ u32 kvm_realm_ipa_limit(void);
 int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
 int kvm_init_realm_vm(struct kvm *kvm);
 void kvm_destroy_realm(struct kvm *kvm);
+void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
+
+#define RME_RTT_BLOCK_LEVEL	2
+#define RME_RTT_MAX_LEVEL	3
+
+#define RME_PAGE_SHIFT		12
+#define RME_PAGE_SIZE		BIT(RME_PAGE_SHIFT)
+/* See ARM64_HW_PGTABLE_LEVEL_SHIFT() */
+#define RME_RTT_LEVEL_SHIFT(l)	\
+	((RME_PAGE_SHIFT - 3) * (4 - (l)) + 3)
+#define RME_L2_BLOCK_SIZE	BIT(RME_RTT_LEVEL_SHIFT(2))
+
+static inline unsigned long rme_rtt_level_mapsize(int level)
+{
+	if (WARN_ON(level > RME_RTT_MAX_LEVEL))
+		return RME_PAGE_SIZE;
+
+	return (1UL << RME_RTT_LEVEL_SHIFT(level));
+}
 
 #endif
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 4e6a1e39ceb3..d0e4642dadc9 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1054,17 +1054,17 @@ void stage2_unmap_vm(struct kvm *kvm)
 void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 {
 	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
-	struct kvm_pgtable *pgt = NULL;
+	struct kvm_pgtable *pgt;
 
 	write_lock(&kvm->mmu_lock);
+	pgt = mmu->pgt;
 	if (kvm_is_realm(kvm) &&
 	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
 	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
-		/* Tearing down RTTs will be added in a later patch */
 		write_unlock(&kvm->mmu_lock);
+		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
 		return;
 	}
-	pgt = mmu->pgt;
 	if (pgt) {
 		mmu->pgd_phys = 0;
 		mmu->pgt = NULL;
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index f6430d460519..7db405d2b2b2 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -125,6 +125,119 @@ static int realm_create_rd(struct kvm *kvm)
 	return r;
 }
 
+static int realm_rtt_destroy(struct realm *realm, unsigned long addr,
+			     int level, phys_addr_t *rtt_granule,
+			     unsigned long *next_addr)
+{
+	unsigned long out_rtt;
+	int ret;
+
+	ret = rmi_rtt_destroy(virt_to_phys(realm->rd), addr, level,
+			      &out_rtt, next_addr);
+
+	*rtt_granule = out_rtt;
+
+	return ret;
+}
+
+static int realm_tear_down_rtt_level(struct realm *realm, int level,
+				     unsigned long start, unsigned long end)
+{
+	ssize_t map_size;
+	unsigned long addr, next_addr;
+
+	if (WARN_ON(level > RME_RTT_MAX_LEVEL))
+		return -EINVAL;
+
+	map_size = rme_rtt_level_mapsize(level - 1);
+
+	for (addr = start; addr < end; addr = next_addr) {
+		phys_addr_t rtt_granule;
+		int ret;
+		unsigned long align_addr = ALIGN(addr, map_size);
+
+		next_addr = ALIGN(addr + 1, map_size);
+
+		if (next_addr > end || align_addr != addr) {
+			/*
+			 * The target range is smaller than what this level
+			 * covers, recurse deeper.
+			 */
+			ret = realm_tear_down_rtt_level(realm,
+							level + 1,
+							addr,
+							min(next_addr, end));
+			if (ret)
+				return ret;
+			continue;
+		}
+
+		ret = realm_rtt_destroy(realm, addr, level,
+					&rtt_granule, &next_addr);
+
+		switch (RMI_RETURN_STATUS(ret)) {
+		case RMI_SUCCESS:
+			if (!WARN_ON(rmi_granule_undelegate(rtt_granule)))
+				free_page((unsigned long)phys_to_virt(rtt_granule));
+			break;
+		case RMI_ERROR_RTT:
+			if (next_addr > addr) {
+				/* Missing RTT, skip */
+				break;
+			}
+			if (WARN_ON(RMI_RETURN_INDEX(ret) != level))
+				return -EBUSY;
+			/*
+			 * We tear down the RTT range for the full IPA
+			 * space, after everything is unmapped. Also we
+			 * descend down only if we cannot tear down a
+			 * top level RTT. Thus RMM must be able to walk
+			 * to the requested level. e.g., a block mapping
+			 * exists at L1 or L2.
+			 */
+			if (WARN_ON(level == RME_RTT_MAX_LEVEL))
+				return -EBUSY;
+
+			/*
+			 * The table has active entries in it, recurse deeper
+			 * and tear down the RTTs.
+			 */
+			next_addr = ALIGN(addr + 1, map_size);
+			ret = realm_tear_down_rtt_level(realm,
+							level + 1,
+							addr,
+							next_addr);
+			if (ret)
+				return ret;
+			/*
+			 * Now that the child RTTs are destroyed,
+			 * retry at this level.
+			 */
+			next_addr = addr;
+			break;
+		default:
+			WARN_ON(1);
+			return -ENXIO;
+		}
+	}
+
+	return 0;
+}
+
+static int realm_tear_down_rtt_range(struct realm *realm,
+				     unsigned long start, unsigned long end)
+{
+	return realm_tear_down_rtt_level(realm, get_start_level(realm) + 1,
+					 start, end);
+}
+
+void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits)
+{
+	struct realm *realm = &kvm->arch.realm;
+
+	WARN_ON(realm_tear_down_rtt_range(realm, 0, (1UL << ia_bits)));
+}
+
 /* Protects access to rme_vmid_bitmap */
 static DEFINE_SPINLOCK(rme_vmid_lock);
 static unsigned long *rme_vmid_bitmap;
-- 
2.34.1

[PATCH v4 14/43] arm64: RME: Allocate/free RECs to match vCPUs

[Steven Price]

The RMM maintains a data structure known as the Realm Execution Context
(or REC). It is similar to struct kvm_vcpu and tracks the state of the
virtual CPUs. KVM must delegate memory and request the structures are
created when vCPUs are created, and suitably tear down on destruction.

RECs must also be supplied with addition pages - auxiliary (or AUX)
granules - for storing the larger registers state (e.g. for SVE). The
number of AUX granules for a REC depends on the parameters with which
the Realm was created - the RMM makes this information available via the
RMI_REC_AUX_COUNT call performed after creating the Realm Descriptor (RD).

Note that only some of register state for the REC can be set by KVM, the
rest is defined by the RMM (zeroed). The register state then cannot be
changed by KVM after the REC is created (except when the guest
explicitly requests this e.g. by performing a PSCI call).

See Realm Management Monitor specification (DEN0137) for more information:
https://developer.arm.com/documentation/den0137/

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Free rec->run earlier in kvm_destroy_realm() and adapt to previous patches.
---
 arch/arm64/include/asm/kvm_emulate.h |   2 +
 arch/arm64/include/asm/kvm_host.h    |   3 +
 arch/arm64/include/asm/kvm_rme.h     |  18 ++++
 arch/arm64/kvm/arm.c                 |   2 +
 arch/arm64/kvm/reset.c               |  11 ++
 arch/arm64/kvm/rme.c                 | 155 +++++++++++++++++++++++++++
 6 files changed, 191 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 5edcfb1b6c68..7430c77574e3 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -712,6 +712,8 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
 
 static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
 {
+	if (static_branch_unlikely(&kvm_rme_is_available))
+		return vcpu->arch.rec.mpidr != INVALID_HWID;
 	return false;
 }
 
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e36be05b97f8..27e4ae382b38 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -755,6 +755,9 @@ struct kvm_vcpu_arch {
 
 	/* Per-vcpu CCSIDR override or NULL */
 	u32 *ccsidr;
+
+	/* Realm meta data */
+	struct realm_rec rec;
 };
 
 /*
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index e5704859a6e5..3a3aaf5d591c 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -6,6 +6,7 @@
 #ifndef __ASM_KVM_RME_H
 #define __ASM_KVM_RME_H
 
+#include <asm/rmi_smc.h>
 #include <uapi/linux/kvm.h>
 
 /**
@@ -70,6 +71,21 @@ struct realm {
 	unsigned int ia_bits;
 };
 
+/**
+ * struct realm_rec - Additional per VCPU data for a Realm
+ *
+ * @mpidr: MPIDR (Multiprocessor Affinity Register) value to identify this VCPU
+ * @rec_page: Kernel VA of the RMM's private page for this REC
+ * @aux_pages: Additional pages private to the RMM for this REC
+ * @run: Kernel VA of the RmiRecRun structure shared with the RMM
+ */
+struct realm_rec {
+	unsigned long mpidr;
+	void *rec_page;
+	struct page *aux_pages[REC_PARAMS_AUX_GRANULES];
+	struct rec_run *run;
+};
+
 void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
 
@@ -77,6 +93,8 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
 int kvm_init_realm_vm(struct kvm *kvm);
 void kvm_destroy_realm(struct kvm *kvm);
 void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
+int kvm_create_rec(struct kvm_vcpu *vcpu);
+void kvm_destroy_rec(struct kvm_vcpu *vcpu);
 
 #define RME_RTT_BLOCK_LEVEL	2
 #define RME_RTT_MAX_LEVEL	3
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index fb1ed1f44561..89432ccee389 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -522,6 +522,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	/* Force users to call KVM_ARM_VCPU_INIT */
 	vcpu_clear_flag(vcpu, VCPU_INITIALIZED);
 
+	vcpu->arch.rec.mpidr = INVALID_HWID;
+
 	vcpu->arch.mmu_page_cache.gfp_zero = __GFP_ZERO;
 
 	/* Set up the timer */
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 0b0ae5ae7bc2..845b1ece47d4 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -137,6 +137,11 @@ int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
 			return -EPERM;
 
 		return kvm_vcpu_finalize_sve(vcpu);
+	case KVM_ARM_VCPU_REC:
+		if (!kvm_is_realm(vcpu->kvm))
+			return -EINVAL;
+
+		return kvm_create_rec(vcpu);
 	}
 
 	return -EINVAL;
@@ -147,6 +152,11 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
 	if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
 		return false;
 
+	if (kvm_is_realm(vcpu->kvm) &&
+	    !(vcpu_is_rec(vcpu) &&
+	      READ_ONCE(vcpu->kvm->arch.realm.state) == REALM_STATE_ACTIVE))
+		return false;
+
 	return true;
 }
 
@@ -159,6 +169,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
 		kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
 	kfree(sve_state);
 	kfree(vcpu->arch.ccsidr);
+	kvm_destroy_rec(vcpu);
 }
 
 static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 7db405d2b2b2..6f0ced6e0cc1 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -422,6 +422,161 @@ void kvm_destroy_realm(struct kvm *kvm)
 	kvm_free_stage2_pgd(&kvm->arch.mmu);
 }
 
+static void free_rec_aux(struct page **aux_pages,
+			 unsigned int num_aux)
+{
+	unsigned int i;
+
+	for (i = 0; i < num_aux; i++) {
+		phys_addr_t aux_page_phys = page_to_phys(aux_pages[i]);
+
+		/* If the undelegate fails then leak the page */
+		if (WARN_ON(rmi_granule_undelegate(aux_page_phys)))
+			continue;
+
+		__free_page(aux_pages[i]);
+	}
+}
+
+static int alloc_rec_aux(struct page **aux_pages,
+			 u64 *aux_phys_pages,
+			 unsigned int num_aux)
+{
+	int ret;
+	unsigned int i;
+
+	for (i = 0; i < num_aux; i++) {
+		struct page *aux_page;
+		phys_addr_t aux_page_phys;
+
+		aux_page = alloc_page(GFP_KERNEL);
+		if (!aux_page) {
+			ret = -ENOMEM;
+			goto out_err;
+		}
+		aux_page_phys = page_to_phys(aux_page);
+		if (rmi_granule_delegate(aux_page_phys)) {
+			__free_page(aux_page);
+			ret = -ENXIO;
+			goto out_err;
+		}
+		aux_pages[i] = aux_page;
+		aux_phys_pages[i] = aux_page_phys;
+	}
+
+	return 0;
+out_err:
+	free_rec_aux(aux_pages, i);
+	return ret;
+}
+
+int kvm_create_rec(struct kvm_vcpu *vcpu)
+{
+	struct user_pt_regs *vcpu_regs = vcpu_gp_regs(vcpu);
+	unsigned long mpidr = kvm_vcpu_get_mpidr_aff(vcpu);
+	struct realm *realm = &vcpu->kvm->arch.realm;
+	struct realm_rec *rec = &vcpu->arch.rec;
+	unsigned long rec_page_phys;
+	struct rec_params *params;
+	int r, i;
+
+	if (kvm_realm_state(vcpu->kvm) != REALM_STATE_NEW)
+		return -ENOENT;
+
+	/*
+	 * The RMM will report PSCI v1.0 to Realms and the KVM_ARM_VCPU_PSCI_0_2
+	 * flag covers v0.2 and onwards.
+	 */
+	if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_PSCI_0_2))
+		return -EINVAL;
+
+	BUILD_BUG_ON(sizeof(*params) > PAGE_SIZE);
+	BUILD_BUG_ON(sizeof(*rec->run) > PAGE_SIZE);
+
+	params = (struct rec_params *)get_zeroed_page(GFP_KERNEL);
+	rec->rec_page = (void *)__get_free_page(GFP_KERNEL);
+	rec->run = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!params || !rec->rec_page || !rec->run) {
+		r = -ENOMEM;
+		goto out_free_pages;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(params->gprs); i++)
+		params->gprs[i] = vcpu_regs->regs[i];
+
+	params->pc = vcpu_regs->pc;
+
+	if (vcpu->vcpu_id == 0)
+		params->flags |= REC_PARAMS_FLAG_RUNNABLE;
+
+	rec_page_phys = virt_to_phys(rec->rec_page);
+
+	if (rmi_granule_delegate(rec_page_phys)) {
+		r = -ENXIO;
+		goto out_free_pages;
+	}
+
+	r = alloc_rec_aux(rec->aux_pages, params->aux, realm->num_aux);
+	if (r)
+		goto out_undelegate_rmm_rec;
+
+	params->num_rec_aux = realm->num_aux;
+	params->mpidr = mpidr;
+
+	if (rmi_rec_create(virt_to_phys(realm->rd),
+			   rec_page_phys,
+			   virt_to_phys(params))) {
+		r = -ENXIO;
+		goto out_free_rec_aux;
+	}
+
+	rec->mpidr = mpidr;
+
+	free_page((unsigned long)params);
+	return 0;
+
+out_free_rec_aux:
+	free_rec_aux(rec->aux_pages, realm->num_aux);
+out_undelegate_rmm_rec:
+	if (WARN_ON(rmi_granule_undelegate(rec_page_phys)))
+		rec->rec_page = NULL;
+out_free_pages:
+	free_page((unsigned long)rec->run);
+	free_page((unsigned long)rec->rec_page);
+	free_page((unsigned long)params);
+	return r;
+}
+
+void kvm_destroy_rec(struct kvm_vcpu *vcpu)
+{
+	struct realm *realm = &vcpu->kvm->arch.realm;
+	struct realm_rec *rec = &vcpu->arch.rec;
+	unsigned long rec_page_phys;
+
+	if (!vcpu_is_rec(vcpu))
+		return;
+
+	free_page((unsigned long)rec->run);
+
+	rec_page_phys = virt_to_phys(rec->rec_page);
+
+	/*
+	 * The REC and any AUX pages cannot be reclaimed until the REC is
+	 * destroyed. So if the REC destroy fails then the REC page and any AUX
+	 * pages will be leaked.
+	 */
+	if (WARN_ON(rmi_rec_destroy(rec_page_phys)))
+		return;
+
+	free_rec_aux(rec->aux_pages, realm->num_aux);
+
+	/* If the undelegate fails then leak the REC page */
+	if (WARN_ON(rmi_granule_undelegate(rec_page_phys)))
+		return;
+
+	free_page((unsigned long)rec->rec_page);
+}
+
 int kvm_init_realm_vm(struct kvm *kvm)
 {
 	struct realm_params *params;
-- 
2.34.1

[PATCH v4 15/43] arm64: RME: Support for the VGIC in realms

[Steven Price]

The RMM provides emulation of a VGIC to the realm guest but delegates
much of the handling to the host. Implement support in KVM for
saving/restoring state to/from the REC structure.

Signed-off-by: Steven Price <steven.price@arm.com>
---
v3: Changes to adapt to rebasing only.
---
 arch/arm64/kvm/arm.c          | 15 +++++++++++---
 arch/arm64/kvm/vgic/vgic-v3.c |  8 +++++++-
 arch/arm64/kvm/vgic/vgic.c    | 37 +++++++++++++++++++++++++++++++++--
 3 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 89432ccee389..568e9e6e5a4e 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -689,19 +689,24 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+	kvm_timer_vcpu_put(vcpu);
+	kvm_vgic_put(vcpu);
+
+	vcpu->cpu = -1;
+
+	if (vcpu_is_rec(vcpu))
+		return;
+
 	kvm_arch_vcpu_put_debug_state_flags(vcpu);
 	kvm_arch_vcpu_put_fp(vcpu);
 	if (has_vhe())
 		kvm_vcpu_put_vhe(vcpu);
-	kvm_timer_vcpu_put(vcpu);
-	kvm_vgic_put(vcpu);
 	kvm_vcpu_pmu_restore_host(vcpu);
 	if (vcpu_has_nv(vcpu))
 		kvm_vcpu_put_hw_mmu(vcpu);
 	kvm_arm_vmid_clear_active();
 
 	vcpu_clear_on_unsupported_cpu(vcpu);
-	vcpu->cpu = -1;
 }
 
 static void __kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu)
@@ -911,6 +916,10 @@ int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu)
 	}
 
 	if (!irqchip_in_kernel(kvm)) {
+		/* Userspace irqchip not yet supported with Realms */
+		if (kvm_is_realm(vcpu->kvm))
+			return -EOPNOTSUPP;
+
 		/*
 		 * Tell the rest of the code that there are userspace irqchip
 		 * VMs in the wild.
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index ed6e412cd74b..ffb42966fe63 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -7,9 +7,11 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <kvm/arm_vgic.h>
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_asm.h>
+#include <asm/rmi_smc.h>
 
 #include "vgic.h"
 
@@ -667,7 +669,8 @@ int vgic_v3_probe(const struct gic_kvm_info *info)
 			(unsigned long long)info->vcpu.start);
 	} else if (kvm_get_mode() != KVM_MODE_PROTECTED) {
 		kvm_vgic_global_state.vcpu_base = info->vcpu.start;
-		kvm_vgic_global_state.can_emulate_gicv2 = true;
+		if (!static_branch_unlikely(&kvm_rme_is_available))
+			kvm_vgic_global_state.can_emulate_gicv2 = true;
 		ret = kvm_register_vgic_device(KVM_DEV_TYPE_ARM_VGIC_V2);
 		if (ret) {
 			kvm_err("Cannot register GICv2 KVM device.\n");
@@ -734,6 +737,9 @@ void vgic_v3_put(struct kvm_vcpu *vcpu)
 {
 	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
 
+	if (vcpu_is_rec(vcpu))
+		cpu_if->vgic_vmcr = vcpu->arch.rec.run->exit.gicv3_vmcr;
+
 	kvm_call_hyp(__vgic_v3_save_vmcr_aprs, cpu_if);
 	WARN_ON(vgic_v4_put(vcpu));
 
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index f07b3ddff7d4..46f7065e993c 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -10,7 +10,9 @@
 #include <linux/list_sort.h>
 #include <linux/nospec.h>
 
+#include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
+#include <asm/rmi_smc.h>
 
 #include "vgic.h"
 
@@ -843,10 +845,23 @@ static inline bool can_access_vgic_from_kernel(void)
 	return !static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) || has_vhe();
 }
 
+static inline void vgic_rmm_save_state(struct kvm_vcpu *vcpu)
+{
+	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	int i;
+
+	for (i = 0; i < kvm_vgic_global_state.nr_lr; i++) {
+		cpu_if->vgic_lr[i] = vcpu->arch.rec.run->exit.gicv3_lrs[i];
+		vcpu->arch.rec.run->enter.gicv3_lrs[i] = 0;
+	}
+}
+
 static inline void vgic_save_state(struct kvm_vcpu *vcpu)
 {
 	if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 		vgic_v2_save_state(vcpu);
+	else if (vcpu_is_rec(vcpu))
+		vgic_rmm_save_state(vcpu);
 	else
 		__vgic_v3_save_state(&vcpu->arch.vgic_cpu.vgic_v3);
 }
@@ -873,10 +888,28 @@ void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu)
 	vgic_prune_ap_list(vcpu);
 }
 
+static inline void vgic_rmm_restore_state(struct kvm_vcpu *vcpu)
+{
+	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
+	int i;
+
+	for (i = 0; i < kvm_vgic_global_state.nr_lr; i++) {
+		vcpu->arch.rec.run->enter.gicv3_lrs[i] = cpu_if->vgic_lr[i];
+		/*
+		 * Also populate the rec.run->exit copies so that a late
+		 * decision to back out from entering the realm doesn't cause
+		 * the state to be lost
+		 */
+		vcpu->arch.rec.run->exit.gicv3_lrs[i] = cpu_if->vgic_lr[i];
+	}
+}
+
 static inline void vgic_restore_state(struct kvm_vcpu *vcpu)
 {
 	if (!static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif))
 		vgic_v2_restore_state(vcpu);
+	else if (vcpu_is_rec(vcpu))
+		vgic_rmm_restore_state(vcpu);
 	else
 		__vgic_v3_restore_state(&vcpu->arch.vgic_cpu.vgic_v3);
 }
@@ -917,7 +950,7 @@ void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu)
 
 void kvm_vgic_load(struct kvm_vcpu *vcpu)
 {
-	if (unlikely(!vgic_initialized(vcpu->kvm)))
+	if (unlikely(!vgic_initialized(vcpu->kvm)) || vcpu_is_rec(vcpu))
 		return;
 
 	if (kvm_vgic_global_state.type == VGIC_V2)
@@ -928,7 +961,7 @@ void kvm_vgic_load(struct kvm_vcpu *vcpu)
 
 void kvm_vgic_put(struct kvm_vcpu *vcpu)
 {
-	if (unlikely(!vgic_initialized(vcpu->kvm)))
+	if (unlikely(!vgic_initialized(vcpu->kvm)) || vcpu_is_rec(vcpu))
 		return;
 
 	if (kvm_vgic_global_state.type == VGIC_V2)
-- 
2.34.1

[PATCH v4 16/43] KVM: arm64: Support timers in realm RECs

[Steven Price]

The RMM keeps track of the timer while the realm REC is running, but on
exit to the normal world KVM is responsible for handling the timers.

A later patch adds the support for propagating the timer values from the
exit data structure and calling kvm_realm_timers_update().

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arch_timer.c  | 45 ++++++++++++++++++++++++++++++++----
 include/kvm/arm_arch_timer.h |  2 ++
 2 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 879982b1cc73..0b2be34a9ba3 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -162,6 +162,13 @@ static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval)
 
 static void timer_set_offset(struct arch_timer_context *ctxt, u64 offset)
 {
+	struct kvm_vcpu *vcpu = ctxt->vcpu;
+
+	if (kvm_is_realm(vcpu->kvm)) {
+		WARN_ON(offset);
+		return;
+	}
+
 	if (!ctxt->offset.vm_offset) {
 		WARN(offset, "timer %ld\n", arch_timer_ctx_index(ctxt));
 		return;
@@ -460,6 +467,21 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
 	}
 }
 
+void kvm_realm_timers_update(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_cpu *arch_timer = &vcpu->arch.timer_cpu;
+	int i;
+
+	for (i = 0; i < NR_KVM_EL0_TIMERS; i++) {
+		struct arch_timer_context *timer = &arch_timer->timers[i];
+		bool status = timer_get_ctl(timer) & ARCH_TIMER_CTRL_IT_STAT;
+		bool level = kvm_timer_irq_can_fire(timer) && status;
+
+		if (level != timer->irq.level)
+			kvm_timer_update_irq(vcpu, level, timer);
+	}
+}
+
 /* Only called for a fully emulated timer */
 static void timer_emulate(struct arch_timer_context *ctx)
 {
@@ -831,6 +853,8 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 	if (unlikely(!timer->enabled))
 		return;
 
+	kvm_timer_unblocking(vcpu);
+
 	get_timer_map(vcpu, &map);
 
 	if (static_branch_likely(&has_gic_active_state)) {
@@ -844,8 +868,6 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 		kvm_timer_vcpu_load_nogic(vcpu);
 	}
 
-	kvm_timer_unblocking(vcpu);
-
 	timer_restore_state(map.direct_vtimer);
 	if (map.direct_ptimer)
 		timer_restore_state(map.direct_ptimer);
@@ -988,7 +1010,9 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 
 	ctxt->vcpu = vcpu;
 
-	if (timerid == TIMER_VTIMER)
+	if (kvm_is_realm(vcpu->kvm))
+		ctxt->offset.vm_offset = NULL;
+	else if (timerid == TIMER_VTIMER)
 		ctxt->offset.vm_offset = &kvm->arch.timer_data.voffset;
 	else
 		ctxt->offset.vm_offset = &kvm->arch.timer_data.poffset;
@@ -1011,13 +1035,19 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
+	u64 cntvoff;
 
 	for (int i = 0; i < NR_KVM_TIMERS; i++)
 		timer_context_init(vcpu, i);
 
+	if (kvm_is_realm(vcpu->kvm))
+		cntvoff = 0;
+	else
+		cntvoff = kvm_phys_timer_read();
+
 	/* Synchronize offsets across timers of a VM if not already provided */
 	if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &vcpu->kvm->arch.flags)) {
-		timer_set_offset(vcpu_vtimer(vcpu), kvm_phys_timer_read());
+		timer_set_offset(vcpu_vtimer(vcpu), cntvoff);
 		timer_set_offset(vcpu_ptimer(vcpu), 0);
 	}
 
@@ -1525,6 +1555,13 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 		return -EINVAL;
 	}
 
+	/*
+	 * We don't use mapped IRQs for Realms because the RMI doesn't allow
+	 * us setting the LR.HW bit in the VGIC.
+	 */
+	if (vcpu_is_rec(vcpu))
+		return 0;
+
 	get_timer_map(vcpu, &map);
 
 	ret = kvm_vgic_map_phys_irq(vcpu,
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index c819c5d16613..d8ab297560d0 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -112,6 +112,8 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr);
 
+void kvm_realm_timers_update(struct kvm_vcpu *vcpu);
+
 u64 kvm_phys_timer_read(void);
 
 void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu);
-- 
2.34.1

[PATCH v4 17/43] arm64: RME: Allow VMM to set RIPAS

[Steven Price]

Each page within the protected region of the realm guest can be marked
as either RAM or EMPTY. Allow the VMM to control this before the guest
has started and provide the equivalent functions to change this (with
the guest's approval) at runtime.

When transitioning from RIPAS RAM (1) to RIPAS EMPTY (0) the memory is
unmapped from the guest and undelegated allowing the memory to be reused
by the host. When transitioning to RIPAS RAM the actual population of
the leaf RTTs is done later on stage 2 fault, however it may be
necessary to allocate additional RTTs to allow the RMM track the RIPAS
for the requested range.

When freeing a block mapping it is necessary to temporarily unfold the
RTT which requires delegating an extra page to the RMM, this page can
then be recovered once the contents of the block mapping have been
freed. A spare, delegated page (spare_page) is used for this purpose.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes from v2:
 * {alloc,free}_delegated_page() moved from previous patch to this one.
 * alloc_delegated_page() now takes a gfp_t flags parameter.
 * Fix the reference counting of guestmem pages to avoid leaking memory.
 * Several misc code improvements and extra comments.
---
 arch/arm64/include/asm/kvm_rme.h |  17 ++
 arch/arm64/kvm/mmu.c             |   8 +-
 arch/arm64/kvm/rme.c             | 481 ++++++++++++++++++++++++++++++-
 3 files changed, 501 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 3a3aaf5d591c..c064bfb080ad 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -96,6 +96,15 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
 int kvm_create_rec(struct kvm_vcpu *vcpu);
 void kvm_destroy_rec(struct kvm_vcpu *vcpu);
 
+void kvm_realm_unmap_range(struct kvm *kvm,
+			   unsigned long ipa,
+			   u64 size,
+			   bool unmap_private);
+int realm_set_ipa_state(struct kvm_vcpu *vcpu,
+			unsigned long addr, unsigned long end,
+			unsigned long ripas,
+			unsigned long *top_ipa);
+
 #define RME_RTT_BLOCK_LEVEL	2
 #define RME_RTT_MAX_LEVEL	3
 
@@ -114,4 +123,12 @@ static inline unsigned long rme_rtt_level_mapsize(int level)
 	return (1UL << RME_RTT_LEVEL_SHIFT(level));
 }
 
+static inline bool realm_is_addr_protected(struct realm *realm,
+					   unsigned long addr)
+{
+	unsigned int ia_bits = realm->ia_bits;
+
+	return !(addr & ~(BIT(ia_bits - 1) - 1));
+}
+
 #endif
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d0e4642dadc9..620d26810019 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -310,6 +310,7 @@ static void invalidate_icache_guest_page(void *va, size_t size)
  * @start: The intermediate physical base address of the range to unmap
  * @size:  The size of the area to unmap
  * @may_block: Whether or not we are permitted to block
+ * @only_shared: If true then protected mappings should not be unmapped
  *
  * Clear a range of stage-2 mappings, lowering the various ref-counts.  Must
  * be called while holding mmu_lock (unless for freeing the stage2 pgd before
@@ -317,7 +318,7 @@ static void invalidate_icache_guest_page(void *va, size_t size)
  * with things behind our backs.
  */
 static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size,
-				 bool may_block)
+				 bool may_block, bool only_shared)
 {
 	struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
 	phys_addr_t end = start + size;
@@ -330,7 +331,7 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
 
 void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
 {
-	__unmap_stage2_range(mmu, start, size, true);
+	__unmap_stage2_range(mmu, start, size, true, false);
 }
 
 void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
@@ -1912,7 +1913,8 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
 
 	__unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
 			     (range->end - range->start) << PAGE_SHIFT,
-			     range->may_block);
+			     range->may_block,
+			     range->only_shared);
 
 	kvm_nested_s2_unmap(kvm);
 	return false;
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 6f0ced6e0cc1..1fa9991d708b 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -47,9 +47,197 @@ static int rmi_check_version(void)
 	return 0;
 }
 
-u32 kvm_realm_ipa_limit(void)
+static phys_addr_t alloc_delegated_page(struct realm *realm,
+					struct kvm_mmu_memory_cache *mc,
+					gfp_t flags)
 {
-	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
+	phys_addr_t phys = PHYS_ADDR_MAX;
+	void *virt;
+
+	if (realm->spare_page != PHYS_ADDR_MAX) {
+		swap(realm->spare_page, phys);
+		goto out;
+	}
+
+	if (mc)
+		virt = kvm_mmu_memory_cache_alloc(mc);
+	else
+		virt = (void *)__get_free_page(flags);
+
+	if (!virt)
+		goto out;
+
+	phys = virt_to_phys(virt);
+
+	if (rmi_granule_delegate(phys)) {
+		free_page((unsigned long)virt);
+
+		phys = PHYS_ADDR_MAX;
+	}
+
+out:
+	return phys;
+}
+
+static void free_delegated_page(struct realm *realm, phys_addr_t phys)
+{
+	if (realm->spare_page == PHYS_ADDR_MAX) {
+		realm->spare_page = phys;
+		return;
+	}
+
+	if (WARN_ON(rmi_granule_undelegate(phys))) {
+		/* Undelegate failed: leak the page */
+		return;
+	}
+
+	free_page((unsigned long)phys_to_virt(phys));
+}
+
+static int realm_rtt_create(struct realm *realm,
+			    unsigned long addr,
+			    int level,
+			    phys_addr_t phys)
+{
+	addr = ALIGN_DOWN(addr, rme_rtt_level_mapsize(level - 1));
+	return rmi_rtt_create(virt_to_phys(realm->rd), phys, addr, level);
+}
+
+static int realm_rtt_fold(struct realm *realm,
+			  unsigned long addr,
+			  int level,
+			  phys_addr_t *rtt_granule)
+{
+	unsigned long out_rtt;
+	int ret;
+
+	ret = rmi_rtt_fold(virt_to_phys(realm->rd), addr, level, &out_rtt);
+
+	if (RMI_RETURN_STATUS(ret) == RMI_SUCCESS && rtt_granule)
+		*rtt_granule = out_rtt;
+
+	return ret;
+}
+
+static int realm_destroy_protected(struct realm *realm,
+				   unsigned long ipa,
+				   unsigned long *next_addr)
+{
+	unsigned long rd = virt_to_phys(realm->rd);
+	unsigned long addr;
+	phys_addr_t rtt;
+	int ret;
+
+loop:
+	ret = rmi_data_destroy(rd, ipa, &addr, next_addr);
+	if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+		if (*next_addr > ipa)
+			return 0; /* UNASSIGNED */
+		rtt = alloc_delegated_page(realm, NULL, GFP_KERNEL);
+		if (WARN_ON(rtt == PHYS_ADDR_MAX))
+			return -1;
+		/*
+		 * ASSIGNED - ipa is mapped as a block, so split. The index
+		 * from the return code should be 2 otherwise it appears
+		 * there's a huge page bigger than allowed
+		 */
+		WARN_ON(RMI_RETURN_INDEX(ret) != 2);
+		ret = realm_rtt_create(realm, ipa, 3, rtt);
+		if (WARN_ON(ret)) {
+			free_delegated_page(realm, rtt);
+			return -1;
+		}
+		/* retry */
+		goto loop;
+	} else if (WARN_ON(ret)) {
+		return -1;
+	}
+	ret = rmi_granule_undelegate(addr);
+
+	/*
+	 * If the undelegate fails then something has gone seriously
+	 * wrong: take an extra reference to just leak the page
+	 */
+	if (!WARN_ON(ret))
+		put_page(phys_to_page(addr));
+
+	return 0;
+}
+
+static void realm_unmap_range_shared(struct kvm *kvm,
+				     int level,
+				     unsigned long start,
+				     unsigned long end)
+{
+	struct realm *realm = &kvm->arch.realm;
+	unsigned long rd = virt_to_phys(realm->rd);
+	ssize_t map_size = rme_rtt_level_mapsize(level);
+	unsigned long next_addr, addr;
+	unsigned long shared_bit = BIT(realm->ia_bits - 1);
+
+	if (WARN_ON(level > RME_RTT_MAX_LEVEL))
+		return;
+
+	start |= shared_bit;
+	end |= shared_bit;
+
+	for (addr = start; addr < end; addr = next_addr) {
+		unsigned long align_addr = ALIGN(addr, map_size);
+		int ret;
+
+		next_addr = ALIGN(addr + 1, map_size);
+
+		if (align_addr != addr || next_addr > end) {
+			/* Need to recurse deeper */
+			if (addr < align_addr)
+				next_addr = align_addr;
+			realm_unmap_range_shared(kvm, level + 1, addr,
+						 min(next_addr, end));
+			continue;
+		}
+
+		ret = rmi_rtt_unmap_unprotected(rd, addr, level, &next_addr);
+		switch (RMI_RETURN_STATUS(ret)) {
+		case RMI_SUCCESS:
+			break;
+		case RMI_ERROR_RTT:
+			if (next_addr == addr) {
+				/*
+				 * There's a mapping here, but it's not a block
+				 * mapping, so reset next_addr to the next block
+				 * boundary and recurse to clear out the pages
+				 * one level deeper.
+				 */
+				next_addr = ALIGN(addr + 1, map_size);
+				realm_unmap_range_shared(kvm, level + 1, addr,
+							 next_addr);
+			}
+			break;
+		default:
+			WARN_ON(1);
+			return;
+		}
+	}
+}
+
+static void realm_unmap_range_private(struct kvm *kvm,
+				      unsigned long start,
+				      unsigned long end)
+{
+	struct realm *realm = &kvm->arch.realm;
+	ssize_t map_size = RME_PAGE_SIZE;
+	unsigned long next_addr, addr;
+
+	for (addr = start; addr < end; addr = next_addr) {
+		int ret;
+
+		next_addr = ALIGN(addr + 1, map_size);
+
+		ret = realm_destroy_protected(realm, addr, &next_addr);
+
+		if (WARN_ON(ret))
+			break;
+	}
 }
 
 static int get_start_level(struct realm *realm)
@@ -57,6 +245,26 @@ static int get_start_level(struct realm *realm)
 	return 4 - stage2_pgtable_levels(realm->ia_bits);
 }
 
+static void realm_unmap_range(struct kvm *kvm,
+			      unsigned long start,
+			      unsigned long end,
+			      bool unmap_private)
+{
+	struct realm *realm = &kvm->arch.realm;
+
+	if (realm->state == REALM_STATE_NONE)
+		return;
+
+	realm_unmap_range_shared(kvm, get_start_level(realm), start, end);
+	if (unmap_private)
+		realm_unmap_range_private(kvm, start, end);
+}
+
+u32 kvm_realm_ipa_limit(void)
+{
+	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
+}
+
 static int realm_create_rd(struct kvm *kvm)
 {
 	struct realm *realm = &kvm->arch.realm;
@@ -140,6 +348,30 @@ static int realm_rtt_destroy(struct realm *realm, unsigned long addr,
 	return ret;
 }
 
+static int realm_create_rtt_levels(struct realm *realm,
+				   unsigned long ipa,
+				   int level,
+				   int max_level,
+				   struct kvm_mmu_memory_cache *mc)
+{
+	if (WARN_ON(level == max_level))
+		return 0;
+
+	while (level++ < max_level) {
+		phys_addr_t rtt = alloc_delegated_page(realm, mc, GFP_KERNEL);
+
+		if (rtt == PHYS_ADDR_MAX)
+			return -ENOMEM;
+
+		if (realm_rtt_create(realm, ipa, level, rtt)) {
+			free_delegated_page(realm, rtt);
+			return -ENXIO;
+		}
+	}
+
+	return 0;
+}
+
 static int realm_tear_down_rtt_level(struct realm *realm, int level,
 				     unsigned long start, unsigned long end)
 {
@@ -231,6 +463,90 @@ static int realm_tear_down_rtt_range(struct realm *realm,
 					 start, end);
 }
 
+/*
+ * Returns 0 on successful fold, a negative value on error, a positive value if
+ * we were not able to fold all tables at this level.
+ */
+static int realm_fold_rtt_level(struct realm *realm, int level,
+				unsigned long start, unsigned long end)
+{
+	int not_folded = 0;
+	ssize_t map_size;
+	unsigned long addr, next_addr;
+
+	if (WARN_ON(level > RME_RTT_MAX_LEVEL))
+		return -EINVAL;
+
+	map_size = rme_rtt_level_mapsize(level - 1);
+
+	for (addr = start; addr < end; addr = next_addr) {
+		phys_addr_t rtt_granule;
+		int ret;
+		unsigned long align_addr = ALIGN(addr, map_size);
+
+		next_addr = ALIGN(addr + 1, map_size);
+
+		ret = realm_rtt_fold(realm, align_addr, level, &rtt_granule);
+
+		switch (RMI_RETURN_STATUS(ret)) {
+		case RMI_SUCCESS:
+			if (!WARN_ON(rmi_granule_undelegate(rtt_granule)))
+				free_page((unsigned long)phys_to_virt(rtt_granule));
+			break;
+		case RMI_ERROR_RTT:
+			if (level == RME_RTT_MAX_LEVEL ||
+			    RMI_RETURN_INDEX(ret) < level) {
+				not_folded++;
+				break;
+			}
+			/* Recurse a level deeper */
+			ret = realm_fold_rtt_level(realm,
+						   level + 1,
+						   addr,
+						   next_addr);
+			if (ret < 0)
+				return ret;
+			else if (ret == 0)
+				/* Try again at this level */
+				next_addr = addr;
+			break;
+		default:
+			WARN_ON(1);
+			return -ENXIO;
+		}
+	}
+
+	return not_folded;
+}
+
+static int realm_fold_rtt_range(struct realm *realm,
+				unsigned long start, unsigned long end)
+{
+	return realm_fold_rtt_level(realm, get_start_level(realm) + 1,
+				    start, end);
+}
+
+static void ensure_spare_page(struct realm *realm)
+{
+	phys_addr_t tmp_rtt;
+
+	/*
+	 * Make sure we have a spare delegated page for tearing down the
+	 * block mappings. We do this by allocating then freeing a page.
+	 * We must use Atomic allocations as we are called with kvm->mmu_lock
+	 * held.
+	 */
+	tmp_rtt = alloc_delegated_page(realm, NULL, GFP_ATOMIC);
+
+	/*
+	 * If the allocation failed, continue as we may not have a block level
+	 * mapping so it may not be fatal, otherwise free it to assign it
+	 * to the spare page.
+	 */
+	if (tmp_rtt != PHYS_ADDR_MAX)
+		free_delegated_page(realm, tmp_rtt);
+}
+
 void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits)
 {
 	struct realm *realm = &kvm->arch.realm;
@@ -238,6 +554,155 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits)
 	WARN_ON(realm_tear_down_rtt_range(realm, 0, (1UL << ia_bits)));
 }
 
+void kvm_realm_unmap_range(struct kvm *kvm, unsigned long ipa, u64 size,
+			   bool unmap_private)
+{
+	unsigned long end = ipa + size;
+	struct realm *realm = &kvm->arch.realm;
+
+	end = min(BIT(realm->ia_bits - 1), end);
+
+	ensure_spare_page(realm);
+
+	realm_unmap_range(kvm, ipa, end, unmap_private);
+
+	if (unmap_private)
+		realm_fold_rtt_range(realm, ipa, end);
+}
+
+static int find_map_level(struct realm *realm,
+			  unsigned long start,
+			  unsigned long end)
+{
+	int level = RME_RTT_MAX_LEVEL;
+
+	while (level > get_start_level(realm)) {
+		unsigned long map_size = rme_rtt_level_mapsize(level - 1);
+
+		if (!IS_ALIGNED(start, map_size) ||
+		    (start + map_size) > end)
+			break;
+
+		level--;
+	}
+
+	return level;
+}
+
+int realm_set_ipa_state(struct kvm_vcpu *vcpu,
+			unsigned long start,
+			unsigned long end,
+			unsigned long ripas,
+			unsigned long *top_ipa)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct realm *realm = &kvm->arch.realm;
+	struct realm_rec *rec = &vcpu->arch.rec;
+	phys_addr_t rd_phys = virt_to_phys(realm->rd);
+	phys_addr_t rec_phys = virt_to_phys(rec->rec_page);
+	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
+	unsigned long ipa = start;
+	int ret = 0;
+
+	while (ipa < end) {
+		unsigned long next;
+
+		ret = rmi_rtt_set_ripas(rd_phys, rec_phys, ipa, end, &next);
+
+		if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+			int walk_level = RMI_RETURN_INDEX(ret);
+			int level = find_map_level(realm, ipa, end);
+
+			/*
+			 * If the RMM walk ended early then more tables are
+			 * needed to reach the required depth to set the RIPAS.
+			 */
+			if (walk_level < level) {
+				ret = realm_create_rtt_levels(realm, ipa,
+							      walk_level,
+							      level,
+							      memcache);
+				/* Retry with RTTs created */
+				if (!ret)
+					continue;
+			} else {
+				ret = -EINVAL;
+			}
+
+			break;
+		} else if (RMI_RETURN_STATUS(ret) != RMI_SUCCESS) {
+			WARN(1, "Unexpected error in %s: %#x\n", __func__,
+			     ret);
+			ret = -EINVAL;
+			break;
+		}
+		ipa = next;
+	}
+
+	*top_ipa = ipa;
+
+	if (ripas == RMI_EMPTY && ipa != start) {
+		realm_unmap_range_private(kvm, start, ipa);
+		realm_fold_rtt_range(realm, start, ipa);
+	}
+
+	return ret;
+}
+
+static int realm_init_ipa_state(struct realm *realm,
+				unsigned long ipa,
+				unsigned long end)
+{
+	phys_addr_t rd_phys = virt_to_phys(realm->rd);
+	int ret;
+
+	while (ipa < end) {
+		unsigned long next;
+
+		ret = rmi_rtt_init_ripas(rd_phys, ipa, end, &next);
+
+		if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+			int err_level = RMI_RETURN_INDEX(ret);
+			int level = find_map_level(realm, ipa, end);
+
+			if (WARN_ON(err_level >= level))
+				return -ENXIO;
+
+			ret = realm_create_rtt_levels(realm, ipa,
+						      err_level,
+						      level, NULL);
+			if (ret)
+				return ret;
+			/* Retry with the RTT levels in place */
+			continue;
+		} else if (WARN_ON(ret)) {
+			return -ENXIO;
+		}
+
+		ipa = next;
+	}
+
+	return 0;
+}
+
+static int kvm_init_ipa_range_realm(struct kvm *kvm,
+				    struct kvm_cap_arm_rme_init_ipa_args *args)
+{
+	gpa_t addr, end;
+	struct realm *realm = &kvm->arch.realm;
+
+	addr = args->init_ipa_base;
+	end = addr + args->init_ipa_size;
+
+	if (end < addr)
+		return -EINVAL;
+
+	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
+		return -EINVAL;
+
+	return realm_init_ipa_state(realm, addr, end);
+}
+
 /* Protects access to rme_vmid_bitmap */
 static DEFINE_SPINLOCK(rme_vmid_lock);
 static unsigned long *rme_vmid_bitmap;
@@ -363,6 +828,18 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 	case KVM_CAP_ARM_RME_CREATE_RD:
 		r = kvm_create_realm(kvm);
 		break;
+	case KVM_CAP_ARM_RME_INIT_IPA_REALM: {
+		struct kvm_cap_arm_rme_init_ipa_args args;
+		void __user *argp = u64_to_user_ptr(cap->args[1]);
+
+		if (copy_from_user(&args, argp, sizeof(args))) {
+			r = -EFAULT;
+			break;
+		}
+
+		r = kvm_init_ipa_range_realm(kvm, &args);
+		break;
+	}
 	default:
 		r = -EINVAL;
 		break;
-- 
2.34.1

[PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Steven Price]

Entering a realm is done using a SMC call to the RMM. On exit the
exit-codes need to be handled slightly differently to the normal KVM
path so define our own functions for realm enter/exit and hook them
in if the guest is a realm guest.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * realm_set_ipa_state() now provides an output parameter for the
   top_iap that was changed. Use this to signal the VMM with the correct
   range that has been transitioned.
 * Adapt to previous patch changes.
---
 arch/arm64/include/asm/kvm_rme.h |   3 +
 arch/arm64/kvm/Makefile          |   2 +-
 arch/arm64/kvm/arm.c             |  19 +++-
 arch/arm64/kvm/rme-exit.c        | 181 +++++++++++++++++++++++++++++++
 arch/arm64/kvm/rme.c             |  11 ++
 5 files changed, 210 insertions(+), 6 deletions(-)
 create mode 100644 arch/arm64/kvm/rme-exit.c

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index c064bfb080ad..0e44b20cfa48 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -96,6 +96,9 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
 int kvm_create_rec(struct kvm_vcpu *vcpu);
 void kvm_destroy_rec(struct kvm_vcpu *vcpu);
 
+int kvm_rec_enter(struct kvm_vcpu *vcpu);
+int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
+
 void kvm_realm_unmap_range(struct kvm *kvm,
 			   unsigned long ipa,
 			   u64 size,
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 5e79e5eee88d..9f893e86cac9 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -21,7 +21,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
 	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
 	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
 	 vgic/vgic-its.o vgic/vgic-debug.o \
-	 rme.o
+	 rme.o rme-exit.o
 
 kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
 kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 568e9e6e5a4e..e8dabb996705 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1282,7 +1282,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		trace_kvm_entry(*vcpu_pc(vcpu));
 		guest_timing_enter_irqoff();
 
-		ret = kvm_arm_vcpu_enter_exit(vcpu);
+		if (vcpu_is_rec(vcpu))
+			ret = kvm_rec_enter(vcpu);
+		else
+			ret = kvm_arm_vcpu_enter_exit(vcpu);
 
 		vcpu->mode = OUTSIDE_GUEST_MODE;
 		vcpu->stat.exits++;
@@ -1336,10 +1339,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 
 		local_irq_enable();
 
-		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
-
 		/* Exit types that need handling before we can be preempted */
-		handle_exit_early(vcpu, ret);
+		if (!vcpu_is_rec(vcpu)) {
+			trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu),
+				       *vcpu_pc(vcpu));
+
+			handle_exit_early(vcpu, ret);
+		}
 
 		preempt_enable();
 
@@ -1362,7 +1368,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 			ret = ARM_EXCEPTION_IL;
 		}
 
-		ret = handle_exit(vcpu, ret);
+		if (vcpu_is_rec(vcpu))
+			ret = handle_rme_exit(vcpu, ret);
+		else
+			ret = handle_exit(vcpu, ret);
 	}
 
 	/* Tell userspace about in-kernel device output levels */
diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
new file mode 100644
index 000000000000..f4e45d475798
--- /dev/null
+++ b/arch/arm64/kvm/rme-exit.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2023 ARM Ltd.
+ */
+
+#include <linux/kvm_host.h>
+#include <kvm/arm_hypercalls.h>
+#include <kvm/arm_psci.h>
+
+#include <asm/rmi_smc.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_rme.h>
+#include <asm/kvm_mmu.h>
+
+typedef int (*exit_handler_fn)(struct kvm_vcpu *vcpu);
+
+static int rec_exit_reason_notimpl(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	pr_err("[vcpu %d] Unhandled exit reason from realm (ESR: %#llx)\n",
+	       vcpu->vcpu_id, rec->run->exit.esr);
+	return -ENXIO;
+}
+
+static int rec_exit_sync_dabt(struct kvm_vcpu *vcpu)
+{
+	return kvm_handle_guest_abort(vcpu);
+}
+
+static int rec_exit_sync_iabt(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	pr_err("[vcpu %d] Unhandled instruction abort (ESR: %#llx).\n",
+	       vcpu->vcpu_id, rec->run->exit.esr);
+	return -ENXIO;
+}
+
+static int rec_exit_sys_reg(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+	unsigned long esr = kvm_vcpu_get_esr(vcpu);
+	int rt = kvm_vcpu_sys_get_rt(vcpu);
+	bool is_write = !(esr & 1);
+	int ret;
+
+	if (is_write)
+		vcpu_set_reg(vcpu, rt, rec->run->exit.gprs[0]);
+
+	ret = kvm_handle_sys_reg(vcpu);
+
+	if (ret >= 0 && !is_write)
+		rec->run->enter.gprs[0] = vcpu_get_reg(vcpu, rt);
+
+	return ret;
+}
+
+static exit_handler_fn rec_exit_handlers[] = {
+	[0 ... ESR_ELx_EC_MAX]	= rec_exit_reason_notimpl,
+	[ESR_ELx_EC_SYS64]	= rec_exit_sys_reg,
+	[ESR_ELx_EC_DABT_LOW]	= rec_exit_sync_dabt,
+	[ESR_ELx_EC_IABT_LOW]	= rec_exit_sync_iabt
+};
+
+static int rec_exit_psci(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+	int i;
+	int ret;
+
+	for (i = 0; i < REC_RUN_GPRS; i++)
+		vcpu_set_reg(vcpu, i, rec->run->exit.gprs[i]);
+
+	ret = kvm_smccc_call_handler(vcpu);
+
+	for (i = 0; i < REC_RUN_GPRS; i++)
+		rec->run->enter.gprs[i] = vcpu_get_reg(vcpu, i);
+
+	return ret;
+}
+
+static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+	struct realm *realm = &kvm->arch.realm;
+	struct realm_rec *rec = &vcpu->arch.rec;
+	unsigned long base = rec->run->exit.ripas_base;
+	unsigned long top = rec->run->exit.ripas_top;
+	unsigned long ripas = rec->run->exit.ripas_value & 1;
+	unsigned long top_ipa;
+	int ret = -EINVAL;
+
+	if (realm_is_addr_protected(realm, base) &&
+	    realm_is_addr_protected(realm, top - 1)) {
+		kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_cache,
+					   kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
+		write_lock(&kvm->mmu_lock);
+		ret = realm_set_ipa_state(vcpu, base, top, ripas, &top_ipa);
+		write_unlock(&kvm->mmu_lock);
+	}
+
+	WARN(ret && ret != -ENOMEM,
+	     "Unable to satisfy SET_IPAS for %#lx - %#lx, ripas: %#lx\n",
+	     base, top, ripas);
+
+	/* Exit to VMM to complete the change */
+	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
+				      ripas == 1);
+
+	return 0;
+}
+
+static void update_arch_timer_irq_lines(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	__vcpu_sys_reg(vcpu, CNTV_CTL_EL0) = rec->run->exit.cntv_ctl;
+	__vcpu_sys_reg(vcpu, CNTV_CVAL_EL0) = rec->run->exit.cntv_cval;
+	__vcpu_sys_reg(vcpu, CNTP_CTL_EL0) = rec->run->exit.cntp_ctl;
+	__vcpu_sys_reg(vcpu, CNTP_CVAL_EL0) = rec->run->exit.cntp_cval;
+
+	kvm_realm_timers_update(vcpu);
+}
+
+/*
+ * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
+ * proper exit to userspace.
+ */
+int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+	u8 esr_ec = ESR_ELx_EC(rec->run->exit.esr);
+	unsigned long status, index;
+
+	status = RMI_RETURN_STATUS(rec_run_ret);
+	index = RMI_RETURN_INDEX(rec_run_ret);
+
+	/*
+	 * If a PSCI_SYSTEM_OFF request raced with a vcpu executing, we might
+	 * see the following status code and index indicating an attempt to run
+	 * a REC when the RD state is SYSTEM_OFF.  In this case, we just need to
+	 * return to user space which can deal with the system event or will try
+	 * to run the KVM VCPU again, at which point we will no longer attempt
+	 * to enter the Realm because we will have a sleep request pending on
+	 * the VCPU as a result of KVM's PSCI handling.
+	 */
+	if (status == RMI_ERROR_REALM && index == 1) {
+		vcpu->run->exit_reason = KVM_EXIT_UNKNOWN;
+		return 0;
+	}
+
+	if (rec_run_ret)
+		return -ENXIO;
+
+	vcpu->arch.fault.esr_el2 = rec->run->exit.esr;
+	vcpu->arch.fault.far_el2 = rec->run->exit.far;
+	vcpu->arch.fault.hpfar_el2 = rec->run->exit.hpfar;
+
+	update_arch_timer_irq_lines(vcpu);
+
+	/* Reset the emulation flags for the next run of the REC */
+	rec->run->enter.flags = 0;
+
+	switch (rec->run->exit.exit_reason) {
+	case RMI_EXIT_SYNC:
+		return rec_exit_handlers[esr_ec](vcpu);
+	case RMI_EXIT_IRQ:
+	case RMI_EXIT_FIQ:
+		return 1;
+	case RMI_EXIT_PSCI:
+		return rec_exit_psci(vcpu);
+	case RMI_EXIT_RIPAS_CHANGE:
+		return rec_exit_ripas_change(vcpu);
+	}
+
+	kvm_pr_unimpl("Unsupported exit reason: %u\n",
+		      rec->run->exit.exit_reason);
+	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+	return 0;
+}
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 1fa9991d708b..fd4162af551d 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -899,6 +899,17 @@ void kvm_destroy_realm(struct kvm *kvm)
 	kvm_free_stage2_pgd(&kvm->arch.mmu);
 }
 
+int kvm_rec_enter(struct kvm_vcpu *vcpu)
+{
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	if (kvm_realm_state(vcpu->kvm) != REALM_STATE_ACTIVE)
+		return -EINVAL;
+
+	return rmi_rec_enter(virt_to_phys(rec->rec_page),
+			     virt_to_phys(rec->run));
+}
+
 static void free_rec_aux(struct page **aux_pages,
 			 unsigned int num_aux)
 {
-- 
2.34.1

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> Entering a realm is done using a SMC call to the RMM. On exit the
> exit-codes need to be handled slightly differently to the normal KVM
> path so define our own functions for realm enter/exit and hook them
> in if the guest is a realm guest.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>  * realm_set_ipa_state() now provides an output parameter for the
>    top_iap that was changed. Use this to signal the VMM with the correct
>    range that has been transitioned.
>  * Adapt to previous patch changes.
> ---
>  arch/arm64/include/asm/kvm_rme.h |   3 +
>  arch/arm64/kvm/Makefile          |   2 +-
>  arch/arm64/kvm/arm.c             |  19 +++-
>  arch/arm64/kvm/rme-exit.c        | 181 +++++++++++++++++++++++++++++++
>  arch/arm64/kvm/rme.c             |  11 ++
>  5 files changed, 210 insertions(+), 6 deletions(-)
>  create mode 100644 arch/arm64/kvm/rme-exit.c
>
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index c064bfb080ad..0e44b20cfa48 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -96,6 +96,9 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
>  int kvm_create_rec(struct kvm_vcpu *vcpu);
>  void kvm_destroy_rec(struct kvm_vcpu *vcpu);
>  
> +int kvm_rec_enter(struct kvm_vcpu *vcpu);
> +int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
> +
>  void kvm_realm_unmap_range(struct kvm *kvm,
>  			   unsigned long ipa,
>  			   u64 size,
> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
> index 5e79e5eee88d..9f893e86cac9 100644
> --- a/arch/arm64/kvm/Makefile
> +++ b/arch/arm64/kvm/Makefile
> @@ -21,7 +21,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
>  	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
>  	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
>  	 vgic/vgic-its.o vgic/vgic-debug.o \
> -	 rme.o
> +	 rme.o rme-exit.o
>  
>  kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
>  kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 568e9e6e5a4e..e8dabb996705 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1282,7 +1282,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		trace_kvm_entry(*vcpu_pc(vcpu));
>  		guest_timing_enter_irqoff();
>  
> -		ret = kvm_arm_vcpu_enter_exit(vcpu);
> +		if (vcpu_is_rec(vcpu))
> +			ret = kvm_rec_enter(vcpu);
> +		else
> +			ret = kvm_arm_vcpu_enter_exit(vcpu);
>  
>  		vcpu->mode = OUTSIDE_GUEST_MODE;
>  		vcpu->stat.exits++;
> @@ -1336,10 +1339,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  
>  		local_irq_enable();
>  
> -		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
> -
>  		/* Exit types that need handling before we can be preempted */
> -		handle_exit_early(vcpu, ret);
> +		if (!vcpu_is_rec(vcpu)) {
> +			trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu),
> +				       *vcpu_pc(vcpu));
> +
> +			handle_exit_early(vcpu, ret);
> +		}
>  
>  		preempt_enable();
>  
> @@ -1362,7 +1368,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  			ret = ARM_EXCEPTION_IL;
>  		}
>  
> -		ret = handle_exit(vcpu, ret);
> +		if (vcpu_is_rec(vcpu))
> +			ret = handle_rme_exit(vcpu, ret);
> +		else
> +			ret = handle_exit(vcpu, ret);
>  	}
>

like kvm_rec_enter, should we name this as handle_rec_exit()?

 arch/arm64/include/asm/kvm_rme.h | 2 +-
 arch/arm64/kvm/arm.c             | 2 +-
 arch/arm64/kvm/rme-exit.c        | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index a72e06cf4ea6..cd42c19ca21d 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -102,7 +102,7 @@ int kvm_create_rec(struct kvm_vcpu *vcpu);
 void kvm_destroy_rec(struct kvm_vcpu *vcpu);
 
 int kvm_rec_enter(struct kvm_vcpu *vcpu);
-int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
+int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_status);
 
 void kvm_realm_unmap_range(struct kvm *kvm,
 			   unsigned long ipa,
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 05d9062470c2..1e34541d88db 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1391,7 +1391,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 		}
 
 		if (vcpu_is_rec(vcpu))
-			ret = handle_rme_exit(vcpu, ret);
+			ret = handle_rec_exit(vcpu, ret);
 		else
 			ret = handle_exit(vcpu, ret);
 	}
diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
index 0940575b0a14..f888cfe72dfa 100644
--- a/arch/arm64/kvm/rme-exit.c
+++ b/arch/arm64/kvm/rme-exit.c
@@ -156,7 +156,7 @@ static void update_arch_timer_irq_lines(struct kvm_vcpu *vcpu)
  * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
  * proper exit to userspace.
  */
-int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
+int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
 {
 	struct realm_rec *rec = &vcpu->arch.rec;
 	u8 esr_ec = ESR_ELx_EC(rec->run->exit.esr);
-- 

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Steven Price]

On 22/08/2024 04:53, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> Entering a realm is done using a SMC call to the RMM. On exit the
>> exit-codes need to be handled slightly differently to the normal KVM
>> path so define our own functions for realm enter/exit and hook them
>> in if the guest is a realm guest.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>  * realm_set_ipa_state() now provides an output parameter for the
>>    top_iap that was changed. Use this to signal the VMM with the correct
>>    range that has been transitioned.
>>  * Adapt to previous patch changes.
>> ---
>>  arch/arm64/include/asm/kvm_rme.h |   3 +
>>  arch/arm64/kvm/Makefile          |   2 +-
>>  arch/arm64/kvm/arm.c             |  19 +++-
>>  arch/arm64/kvm/rme-exit.c        | 181 +++++++++++++++++++++++++++++++
>>  arch/arm64/kvm/rme.c             |  11 ++
>>  5 files changed, 210 insertions(+), 6 deletions(-)
>>  create mode 100644 arch/arm64/kvm/rme-exit.c
>>
>> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
>> index c064bfb080ad..0e44b20cfa48 100644
>> --- a/arch/arm64/include/asm/kvm_rme.h
>> +++ b/arch/arm64/include/asm/kvm_rme.h
>> @@ -96,6 +96,9 @@ void kvm_realm_destroy_rtts(struct kvm *kvm, u32 ia_bits);
>>  int kvm_create_rec(struct kvm_vcpu *vcpu);
>>  void kvm_destroy_rec(struct kvm_vcpu *vcpu);
>>  
>> +int kvm_rec_enter(struct kvm_vcpu *vcpu);
>> +int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
>> +
>>  void kvm_realm_unmap_range(struct kvm *kvm,
>>  			   unsigned long ipa,
>>  			   u64 size,
>> diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
>> index 5e79e5eee88d..9f893e86cac9 100644
>> --- a/arch/arm64/kvm/Makefile
>> +++ b/arch/arm64/kvm/Makefile
>> @@ -21,7 +21,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
>>  	 vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
>>  	 vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
>>  	 vgic/vgic-its.o vgic/vgic-debug.o \
>> -	 rme.o
>> +	 rme.o rme-exit.o
>>  
>>  kvm-$(CONFIG_HW_PERF_EVENTS)  += pmu-emul.o pmu.o
>>  kvm-$(CONFIG_ARM64_PTR_AUTH)  += pauth.o
>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
>> index 568e9e6e5a4e..e8dabb996705 100644
>> --- a/arch/arm64/kvm/arm.c
>> +++ b/arch/arm64/kvm/arm.c
>> @@ -1282,7 +1282,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  		trace_kvm_entry(*vcpu_pc(vcpu));
>>  		guest_timing_enter_irqoff();
>>  
>> -		ret = kvm_arm_vcpu_enter_exit(vcpu);
>> +		if (vcpu_is_rec(vcpu))
>> +			ret = kvm_rec_enter(vcpu);
>> +		else
>> +			ret = kvm_arm_vcpu_enter_exit(vcpu);
>>  
>>  		vcpu->mode = OUTSIDE_GUEST_MODE;
>>  		vcpu->stat.exits++;
>> @@ -1336,10 +1339,13 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  
>>  		local_irq_enable();
>>  
>> -		trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu), *vcpu_pc(vcpu));
>> -
>>  		/* Exit types that need handling before we can be preempted */
>> -		handle_exit_early(vcpu, ret);
>> +		if (!vcpu_is_rec(vcpu)) {
>> +			trace_kvm_exit(ret, kvm_vcpu_trap_get_class(vcpu),
>> +				       *vcpu_pc(vcpu));
>> +
>> +			handle_exit_early(vcpu, ret);
>> +		}
>>  
>>  		preempt_enable();
>>  
>> @@ -1362,7 +1368,10 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>>  			ret = ARM_EXCEPTION_IL;
>>  		}
>>  
>> -		ret = handle_exit(vcpu, ret);
>> +		if (vcpu_is_rec(vcpu))
>> +			ret = handle_rme_exit(vcpu, ret);
>> +		else
>> +			ret = handle_exit(vcpu, ret);
>>  	}
>>
> 
> like kvm_rec_enter, should we name this as handle_rec_exit()?

Fair enough, will rename.

Steve

> 
>  arch/arm64/include/asm/kvm_rme.h | 2 +-
>  arch/arm64/kvm/arm.c             | 2 +-
>  arch/arm64/kvm/rme-exit.c        | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index a72e06cf4ea6..cd42c19ca21d 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -102,7 +102,7 @@ int kvm_create_rec(struct kvm_vcpu *vcpu);
>  void kvm_destroy_rec(struct kvm_vcpu *vcpu);
>  
>  int kvm_rec_enter(struct kvm_vcpu *vcpu);
> -int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_status);
> +int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_status);
>  
>  void kvm_realm_unmap_range(struct kvm *kvm,
>  			   unsigned long ipa,
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index 05d9062470c2..1e34541d88db 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -1391,7 +1391,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		}
>  
>  		if (vcpu_is_rec(vcpu))
> -			ret = handle_rme_exit(vcpu, ret);
> +			ret = handle_rec_exit(vcpu, ret);
>  		else
>  			ret = handle_exit(vcpu, ret);
>  	}
> diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
> index 0940575b0a14..f888cfe72dfa 100644
> --- a/arch/arm64/kvm/rme-exit.c
> +++ b/arch/arm64/kvm/rme-exit.c
> @@ -156,7 +156,7 @@ static void update_arch_timer_irq_lines(struct kvm_vcpu *vcpu)
>   * Return > 0 to return to guest, < 0 on error, 0 (and set exit_reason) on
>   * proper exit to userspace.
>   */
> -int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
> +int handle_rec_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
>  {
>  	struct realm_rec *rec = &vcpu->arch.rec;
>  	u8 esr_ec = ESR_ELx_EC(rec->run->exit.esr);

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> +	/* Exit to VMM to complete the change */
> +	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
> +				      ripas == 1);
> +


s/1/RMI_RAM ?

May be we can make it an enum like rsi_ripas

modified   arch/arm64/include/asm/rmi_smc.h
@@ -62,9 +62,11 @@
 #define RMI_ERROR_REC		3
 #define RMI_ERROR_RTT		4
 
-#define RMI_EMPTY		0
-#define RMI_RAM			1
-#define RMI_DESTROYED		2
+enum rmi_ripas {
+	RMI_EMPTY,
+	RMI_RAM,
+	RMI_DESTROYED,
+};
 
 #define RMI_NO_MEASURE_CONTENT	0
 #define RMI_MEASURE_CONTENT	1
modified   arch/arm64/kvm/rme-exit.c
@@ -112,7 +112,7 @@ static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
 
 	/* Exit to VMM to complete the change */
 	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
-				      ripas == 1);
+				      ripas == RMI_RAM);
 
 	return 0;
 }

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Steven Price]

On 22/08/2024 04:58, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> +	/* Exit to VMM to complete the change */
>> +	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
>> +				      ripas == 1);
>> +
> 
> 
> s/1/RMI_RAM ?

Ah, good spot - I must have missed that when I added the definitions.

> May be we can make it an enum like rsi_ripas

I guess that makes sense - I tend to avoid enums where the value is
controlled by something external, but here it makes some sense.

Thanks,

Steve

> modified   arch/arm64/include/asm/rmi_smc.h
> @@ -62,9 +62,11 @@
>  #define RMI_ERROR_REC		3
>  #define RMI_ERROR_RTT		4
>  
> -#define RMI_EMPTY		0
> -#define RMI_RAM			1
> -#define RMI_DESTROYED		2
> +enum rmi_ripas {
> +	RMI_EMPTY,
> +	RMI_RAM,
> +	RMI_DESTROYED,
> +};
>  
>  #define RMI_NO_MEASURE_CONTENT	0
>  #define RMI_MEASURE_CONTENT	1
> modified   arch/arm64/kvm/rme-exit.c
> @@ -112,7 +112,7 @@ static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
>  
>  	/* Exit to VMM to complete the change */
>  	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
> -				      ripas == 1);
> +				      ripas == RMI_RAM);
>  
>  	return 0;
>  }

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

....

> +static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	struct realm *realm = &kvm->arch.realm;
> +	struct realm_rec *rec = &vcpu->arch.rec;
> +	unsigned long base = rec->run->exit.ripas_base;
> +	unsigned long top = rec->run->exit.ripas_top;
> +	unsigned long ripas = rec->run->exit.ripas_value & 1;
> +	unsigned long top_ipa;
> +	int ret = -EINVAL;
> +
> +	if (realm_is_addr_protected(realm, base) &&
> +	    realm_is_addr_protected(realm, top - 1)) {
> +		kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_cache,
> +					   kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
> +		write_lock(&kvm->mmu_lock);
> +		ret = realm_set_ipa_state(vcpu, base, top, ripas, &top_ipa);
> +		write_unlock(&kvm->mmu_lock);
> +	}
> +
> +	WARN(ret && ret != -ENOMEM,
> +	     "Unable to satisfy SET_IPAS for %#lx - %#lx, ripas: %#lx\n",
> +	     base, top, ripas);
> +
> +	/* Exit to VMM to complete the change */
> +	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
> +				      ripas == 1);
> +
> +	return 0;
> +}
> +

arch/arm64/kvm/rme-exit.c:100:6: warning: variable 'top_ipa' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
        if (realm_is_addr_protected(realm, base) &&
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/arm64/kvm/rme-exit.c:114:44: note: uninitialized use occurs here
        kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
                                                  ^~~~~~~

-aneesh

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[Steven Price]

On 22/08/2024 05:04, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
> ....
> 
>> +static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
>> +{
>> +	struct kvm *kvm = vcpu->kvm;
>> +	struct realm *realm = &kvm->arch.realm;
>> +	struct realm_rec *rec = &vcpu->arch.rec;
>> +	unsigned long base = rec->run->exit.ripas_base;
>> +	unsigned long top = rec->run->exit.ripas_top;
>> +	unsigned long ripas = rec->run->exit.ripas_value & 1;
>> +	unsigned long top_ipa;
>> +	int ret = -EINVAL;
>> +
>> +	if (realm_is_addr_protected(realm, base) &&
>> +	    realm_is_addr_protected(realm, top - 1)) {
>> +		kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_cache,
>> +					   kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
>> +		write_lock(&kvm->mmu_lock);
>> +		ret = realm_set_ipa_state(vcpu, base, top, ripas, &top_ipa);
>> +		write_unlock(&kvm->mmu_lock);
>> +	}
>> +
>> +	WARN(ret && ret != -ENOMEM,
>> +	     "Unable to satisfy SET_IPAS for %#lx - %#lx, ripas: %#lx\n",
>> +	     base, top, ripas);
>> +
>> +	/* Exit to VMM to complete the change */
>> +	kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
>> +				      ripas == 1);
>> +
>> +	return 0;
>> +}
>> +
> 
> arch/arm64/kvm/rme-exit.c:100:6: warning: variable 'top_ipa' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
>         if (realm_is_addr_protected(realm, base) &&
>             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> arch/arm64/kvm/rme-exit.c:114:44: note: uninitialized use occurs here
>         kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
>                                                   ^~~~~~~

I'm not sure why I didn't notice this before, if the condition is false
then we're hitting the WARN (i.e. this shouldn't happen), but I should
fix that up to handle the situation better.

Steve

Re: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit

[kernel test robot]

Hi Steven,

kernel test robot noticed the following build warnings:

[auto build test WARNING on kvmarm/next]
[also build test WARNING on kvm/queue arm64/for-next/core linus/master v6.11-rc4 next-20240822]
[cannot apply to kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Steven-Price/KVM-Prepare-for-handling-only-shared-mappings-in-mmu_notifier-events/20240821-235327
base:   https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next
patch link:    https://lore.kernel.org/r/20240821153844.60084-19-steven.price%40arm.com
patch subject: [PATCH v4 18/43] arm64: RME: Handle realm enter/exit
config: arm64-allmodconfig (https://download.01.org/0day-ci/archive/20240822/202408222119.6YF3UR6O-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 26670e7fa4f032a019d23d56c6a02926e854e8af)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240822/202408222119.6YF3UR6O-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408222119.6YF3UR6O-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from arch/arm64/kvm/rme-exit.c:6:
   In file included from include/linux/kvm_host.h:16:
   In file included from include/linux/mm.h:2228:
   include/linux/vmstat.h:500:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     500 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     501 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:507:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     507 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     508 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:519:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     519 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     520 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:528:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     528 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     529 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:61:23: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
      61 |         [ESR_ELx_EC_SYS64]      = rec_exit_sys_reg,
         |                                   ^~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:60:27: note: previous initialization is here
      60 |         [0 ... ESR_ELx_EC_MAX]  = rec_exit_reason_notimpl,
         |                                   ^~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:62:26: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
      62 |         [ESR_ELx_EC_DABT_LOW]   = rec_exit_sync_dabt,
         |                                   ^~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:60:27: note: previous initialization is here
      60 |         [0 ... ESR_ELx_EC_MAX]  = rec_exit_reason_notimpl,
         |                                   ^~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:63:26: warning: initializer overrides prior initialization of this subobject [-Winitializer-overrides]
      63 |         [ESR_ELx_EC_IABT_LOW]   = rec_exit_sync_iabt
         |                                   ^~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:60:27: note: previous initialization is here
      60 |         [0 ... ESR_ELx_EC_MAX]  = rec_exit_reason_notimpl,
         |                                   ^~~~~~~~~~~~~~~~~~~~~~~
>> arch/arm64/kvm/rme-exit.c:94:6: warning: variable 'top_ipa' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
      94 |         if (realm_is_addr_protected(realm, base) &&
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      95 |             realm_is_addr_protected(realm, top - 1)) {
         |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:108:44: note: uninitialized use occurs here
     108 |         kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
         |                                                   ^~~~~~~
   arch/arm64/kvm/rme-exit.c:94:2: note: remove the 'if' if its condition is always true
      94 |         if (realm_is_addr_protected(realm, base) &&
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      95 |             realm_is_addr_protected(realm, top - 1)) {
         |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> arch/arm64/kvm/rme-exit.c:94:6: warning: variable 'top_ipa' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
      94 |         if (realm_is_addr_protected(realm, base) &&
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:108:44: note: uninitialized use occurs here
     108 |         kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
         |                                                   ^~~~~~~
   arch/arm64/kvm/rme-exit.c:94:6: note: remove the '&&' if its condition is always true
      94 |         if (realm_is_addr_protected(realm, base) &&
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/arm64/kvm/rme-exit.c:91:23: note: initialize the variable 'top_ipa' to silence this warning
      91 |         unsigned long top_ipa;
         |                              ^
         |                               = 0
   10 warnings generated.


vim +94 arch/arm64/kvm/rme-exit.c

    58	
    59	static exit_handler_fn rec_exit_handlers[] = {
  > 60		[0 ... ESR_ELx_EC_MAX]	= rec_exit_reason_notimpl,
    61		[ESR_ELx_EC_SYS64]	= rec_exit_sys_reg,
    62		[ESR_ELx_EC_DABT_LOW]	= rec_exit_sync_dabt,
    63		[ESR_ELx_EC_IABT_LOW]	= rec_exit_sync_iabt
    64	};
    65	
    66	static int rec_exit_psci(struct kvm_vcpu *vcpu)
    67	{
    68		struct realm_rec *rec = &vcpu->arch.rec;
    69		int i;
    70		int ret;
    71	
    72		for (i = 0; i < REC_RUN_GPRS; i++)
    73			vcpu_set_reg(vcpu, i, rec->run->exit.gprs[i]);
    74	
    75		ret = kvm_smccc_call_handler(vcpu);
    76	
    77		for (i = 0; i < REC_RUN_GPRS; i++)
    78			rec->run->enter.gprs[i] = vcpu_get_reg(vcpu, i);
    79	
    80		return ret;
    81	}
    82	
    83	static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
    84	{
    85		struct kvm *kvm = vcpu->kvm;
    86		struct realm *realm = &kvm->arch.realm;
    87		struct realm_rec *rec = &vcpu->arch.rec;
    88		unsigned long base = rec->run->exit.ripas_base;
    89		unsigned long top = rec->run->exit.ripas_top;
    90		unsigned long ripas = rec->run->exit.ripas_value & 1;
    91		unsigned long top_ipa;
    92		int ret = -EINVAL;
    93	
  > 94		if (realm_is_addr_protected(realm, base) &&
    95		    realm_is_addr_protected(realm, top - 1)) {
    96			kvm_mmu_topup_memory_cache(&vcpu->arch.mmu_page_cache,
    97						   kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
    98			write_lock(&kvm->mmu_lock);
    99			ret = realm_set_ipa_state(vcpu, base, top, ripas, &top_ipa);
   100			write_unlock(&kvm->mmu_lock);
   101		}
   102	
   103		WARN(ret && ret != -ENOMEM,
   104		     "Unable to satisfy SET_IPAS for %#lx - %#lx, ripas: %#lx\n",
   105		     base, top, ripas);
   106	
   107		/* Exit to VMM to complete the change */
 > 108		kvm_prepare_memory_fault_exit(vcpu, base, top_ipa - base, false, false,
   109					      ripas == 1);
   110	
   111		return 0;
   112	}
   113	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v4 19/43] KVM: arm64: Handle realm MMIO emulation

[Steven Price]

MMIO emulation for a realm cannot be done directly with the VM's
registers as they are protected from the host. However, for emulatable
data aborts, the RMM uses GPRS[0] to provide the read/written value.
We can transfer this from/to the equivalent VCPU's register entry and
then depend on the generic MMIO handling code in KVM.

For a MMIO read, the value is placed in the shared RecExit structure
during kvm_handle_mmio_return() rather than in the VCPU's register
entry.

Signed-off-by: Steven Price <steven.price@arm.com>
---
v3: Adapt to previous patch changes
---
 arch/arm64/kvm/mmio.c     | 10 +++++++++-
 arch/arm64/kvm/rme-exit.c |  6 ++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/mmio.c b/arch/arm64/kvm/mmio.c
index cd6b7b83e2c3..dbd06ca368e8 100644
--- a/arch/arm64/kvm/mmio.c
+++ b/arch/arm64/kvm/mmio.c
@@ -6,6 +6,7 @@
 
 #include <linux/kvm_host.h>
 #include <asm/kvm_emulate.h>
+#include <asm/rmi_smc.h>
 #include <trace/events/kvm.h>
 
 #include "trace.h"
@@ -90,6 +91,9 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
 
 	vcpu->mmio_needed = 0;
 
+	if (vcpu_is_rec(vcpu))
+		vcpu->arch.rec.run->enter.flags |= RMI_EMULATED_MMIO;
+
 	if (!kvm_vcpu_dabt_iswrite(vcpu)) {
 		struct kvm_run *run = vcpu->run;
 
@@ -108,7 +112,11 @@ int kvm_handle_mmio_return(struct kvm_vcpu *vcpu)
 		trace_kvm_mmio(KVM_TRACE_MMIO_READ, len, run->mmio.phys_addr,
 			       &data);
 		data = vcpu_data_host_to_guest(vcpu, data, len);
-		vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), data);
+
+		if (vcpu_is_rec(vcpu))
+			vcpu->arch.rec.run->enter.gprs[0] = data;
+		else
+			vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu), data);
 	}
 
 	/*
diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
index f4e45d475798..03ed147f7926 100644
--- a/arch/arm64/kvm/rme-exit.c
+++ b/arch/arm64/kvm/rme-exit.c
@@ -25,6 +25,12 @@ static int rec_exit_reason_notimpl(struct kvm_vcpu *vcpu)
 
 static int rec_exit_sync_dabt(struct kvm_vcpu *vcpu)
 {
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	if (kvm_vcpu_dabt_iswrite(vcpu) && kvm_vcpu_dabt_isvalid(vcpu))
+		vcpu_set_reg(vcpu, kvm_vcpu_dabt_get_rd(vcpu),
+			     rec->run->exit.gprs[0]);
+
 	return kvm_handle_guest_abort(vcpu);
 }
 
-- 
2.34.1

[PATCH v4 20/43] arm64: RME: Allow populating initial contents

[Steven Price]

The VMM needs to populate the realm with some data before starting (e.g.
a kernel and initrd). This is measured by the RMM and used as part of
the attestation later on.

For now only 4k mappings are supported, future work may add support for
larger mappings.

Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
v3: Minor changes to simplify the code. Make the 4k only RMM mapping
support more obvious with a 'FIXME' in the code.
---
 arch/arm64/kvm/rme.c | 223 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 223 insertions(+)

diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index fd4162af551d..2c4e28b457be 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/kvm_host.h>
+#include <linux/hugetlb.h>
 
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_mmu.h>
@@ -570,6 +571,216 @@ void kvm_realm_unmap_range(struct kvm *kvm, unsigned long ipa, u64 size,
 		realm_fold_rtt_range(realm, ipa, end);
 }
 
+static int realm_create_protected_data_page(struct realm *realm,
+					    unsigned long ipa,
+					    struct page *dst_page,
+					    struct page *src_page,
+					    unsigned long flags)
+{
+	phys_addr_t dst_phys, src_phys;
+	int ret;
+
+	dst_phys = page_to_phys(dst_page);
+	src_phys = page_to_phys(src_page);
+
+	if (rmi_granule_delegate(dst_phys))
+		return -ENXIO;
+
+	ret = rmi_data_create(virt_to_phys(realm->rd), dst_phys, ipa, src_phys,
+			      flags);
+
+	if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+		/* Create missing RTTs and retry */
+		int level = RMI_RETURN_INDEX(ret);
+
+		ret = realm_create_rtt_levels(realm, ipa, level,
+					      RME_RTT_MAX_LEVEL, NULL);
+		if (ret)
+			goto err;
+
+		ret = rmi_data_create(virt_to_phys(realm->rd), dst_phys, ipa,
+				      src_phys, flags);
+	}
+
+	if (!ret)
+		return 0;
+
+err:
+	if (WARN_ON(rmi_granule_undelegate(dst_phys))) {
+		/* Page can't be returned to NS world so is lost */
+		get_page(dst_page);
+	}
+	return -ENXIO;
+}
+
+static int fold_rtt(struct realm *realm, unsigned long addr, int level)
+{
+	phys_addr_t rtt_addr;
+	int ret;
+
+	ret = realm_rtt_fold(realm, addr, level + 1, &rtt_addr);
+	if (ret)
+		return ret;
+
+	free_delegated_page(realm, rtt_addr);
+
+	return 0;
+}
+
+static int populate_par_region(struct kvm *kvm,
+			       phys_addr_t ipa_base,
+			       phys_addr_t ipa_end,
+			       u32 flags)
+{
+	struct realm *realm = &kvm->arch.realm;
+	struct kvm_memory_slot *memslot;
+	gfn_t base_gfn, end_gfn;
+	int idx;
+	phys_addr_t ipa;
+	int ret = 0;
+	struct page *tmp_page;
+	unsigned long data_flags = 0;
+
+	base_gfn = gpa_to_gfn(ipa_base);
+	end_gfn = gpa_to_gfn(ipa_end);
+
+	if (flags & KVM_ARM_RME_POPULATE_FLAGS_MEASURE)
+		data_flags = RMI_MEASURE_CONTENT;
+
+	idx = srcu_read_lock(&kvm->srcu);
+	memslot = gfn_to_memslot(kvm, base_gfn);
+	if (!memslot) {
+		ret = -EFAULT;
+		goto out;
+	}
+
+	/* We require the region to be contained within a single memslot */
+	if (memslot->base_gfn + memslot->npages < end_gfn) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	tmp_page = alloc_page(GFP_KERNEL);
+	if (!tmp_page) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	mmap_read_lock(current->mm);
+
+	ipa = ipa_base;
+	while (ipa < ipa_end) {
+		struct vm_area_struct *vma;
+		unsigned long map_size;
+		unsigned int vma_shift;
+		unsigned long offset;
+		unsigned long hva;
+		struct page *page;
+		kvm_pfn_t pfn;
+		int level;
+
+		hva = gfn_to_hva_memslot(memslot, gpa_to_gfn(ipa));
+		vma = vma_lookup(current->mm, hva);
+		if (!vma) {
+			ret = -EFAULT;
+			break;
+		}
+
+		/* FIXME: Currently we only support 4k sized mappings */
+		vma_shift = PAGE_SHIFT;
+
+		map_size = 1 << vma_shift;
+
+		ipa = ALIGN_DOWN(ipa, map_size);
+
+		switch (map_size) {
+		case RME_L2_BLOCK_SIZE:
+			level = 2;
+			break;
+		case PAGE_SIZE:
+			level = 3;
+			break;
+		default:
+			WARN_ONCE(1, "Unsupport vma_shift %d", vma_shift);
+			ret = -EFAULT;
+			break;
+		}
+
+		pfn = gfn_to_pfn_memslot(memslot, gpa_to_gfn(ipa));
+
+		if (is_error_pfn(pfn)) {
+			ret = -EFAULT;
+			break;
+		}
+
+		if (level < RME_RTT_MAX_LEVEL) {
+			/*
+			 * A temporary RTT is needed during the map, precreate
+			 * it, however if there is an error (e.g. missing
+			 * parent tables) this will be handled in the
+			 * realm_create_protected_data_page() call.
+			 */
+			realm_create_rtt_levels(realm, ipa, level,
+						RME_RTT_MAX_LEVEL, NULL);
+		}
+
+		page = pfn_to_page(pfn);
+
+		for (offset = 0; offset < map_size && !ret;
+		     offset += PAGE_SIZE, page++) {
+			phys_addr_t page_ipa = ipa + offset;
+
+			ret = realm_create_protected_data_page(realm, page_ipa,
+							       page, tmp_page,
+							       data_flags);
+		}
+		if (ret)
+			goto err_release_pfn;
+
+		if (level == 2)
+			fold_rtt(realm, ipa, level);
+
+		ipa += map_size;
+		kvm_release_pfn_dirty(pfn);
+err_release_pfn:
+		if (ret) {
+			kvm_release_pfn_clean(pfn);
+			break;
+		}
+	}
+
+	mmap_read_unlock(current->mm);
+	__free_page(tmp_page);
+
+out:
+	srcu_read_unlock(&kvm->srcu, idx);
+	return ret;
+}
+
+static int kvm_populate_realm(struct kvm *kvm,
+			      struct kvm_cap_arm_rme_populate_realm_args *args)
+{
+	phys_addr_t ipa_base, ipa_end;
+
+	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
+		return -EINVAL;
+
+	if (!IS_ALIGNED(args->populate_ipa_base, PAGE_SIZE) ||
+	    !IS_ALIGNED(args->populate_ipa_size, PAGE_SIZE))
+		return -EINVAL;
+
+	if (args->flags & ~RMI_MEASURE_CONTENT)
+		return -EINVAL;
+
+	ipa_base = args->populate_ipa_base;
+	ipa_end = ipa_base + args->populate_ipa_size;
+
+	if (ipa_end < ipa_base)
+		return -EINVAL;
+
+	return populate_par_region(kvm, ipa_base, ipa_end, args->flags);
+}
+
 static int find_map_level(struct realm *realm,
 			  unsigned long start,
 			  unsigned long end)
@@ -840,6 +1051,18 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		r = kvm_init_ipa_range_realm(kvm, &args);
 		break;
 	}
+	case KVM_CAP_ARM_RME_POPULATE_REALM: {
+		struct kvm_cap_arm_rme_populate_realm_args args;
+		void __user *argp = u64_to_user_ptr(cap->args[1]);
+
+		if (copy_from_user(&args, argp, sizeof(args))) {
+			r = -EFAULT;
+			break;
+		}
+
+		r = kvm_populate_realm(kvm, &args);
+		break;
+	}
 	default:
 		r = -EINVAL;
 		break;
-- 
2.34.1

[PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

At runtime if the realm guest accesses memory which hasn't yet been
mapped then KVM needs to either populate the region or fault the guest.

For memory in the lower (protected) region of IPA a fresh page is
provided to the RMM which will zero the contents. For memory in the
upper (shared) region of IPA, the memory from the memslot is mapped
into the realm VM non secure.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Avoid leaking memory if failing to map it in the realm.
 * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
 * Adapt to changes in previous patches.
---
 arch/arm64/include/asm/kvm_emulate.h |  10 ++
 arch/arm64/include/asm/kvm_rme.h     |  10 ++
 arch/arm64/kvm/mmu.c                 | 120 +++++++++++++++-
 arch/arm64/kvm/rme.c                 | 205 +++++++++++++++++++++++++--
 4 files changed, 325 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 7430c77574e3..0b50572d3719 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -710,6 +710,16 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
 	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
 }
 
+static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
+{
+	if (kvm_is_realm(kvm)) {
+		struct realm *realm = &kvm->arch.realm;
+
+		return BIT(realm->ia_bits - 1);
+	}
+	return 0;
+}
+
 static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
 {
 	if (static_branch_unlikely(&kvm_rme_is_available))
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 0e44b20cfa48..c50854f44674 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -103,6 +103,16 @@ void kvm_realm_unmap_range(struct kvm *kvm,
 			   unsigned long ipa,
 			   u64 size,
 			   bool unmap_private);
+int realm_map_protected(struct realm *realm,
+			unsigned long base_ipa,
+			struct page *dst_page,
+			unsigned long map_size,
+			struct kvm_mmu_memory_cache *memcache);
+int realm_map_non_secure(struct realm *realm,
+			 unsigned long ipa,
+			 struct page *page,
+			 unsigned long map_size,
+			 struct kvm_mmu_memory_cache *memcache);
 int realm_set_ipa_state(struct kvm_vcpu *vcpu,
 			unsigned long addr, unsigned long end,
 			unsigned long ripas,
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 620d26810019..eb8b8d013f3e 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -325,8 +325,13 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
 
 	lockdep_assert_held_write(&kvm->mmu_lock);
 	WARN_ON(size & ~PAGE_MASK);
-	WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
-				   may_block));
+
+	if (kvm_is_realm(kvm))
+		kvm_realm_unmap_range(kvm, start, size, !only_shared);
+	else
+		WARN_ON(stage2_apply_range(mmu, start, end,
+					   kvm_pgtable_stage2_unmap,
+					   may_block));
 }
 
 void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
@@ -345,7 +350,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
 	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
 	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
 
-	kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
+	if (kvm_is_realm(kvm))
+		kvm_realm_unmap_range(kvm, addr, end - addr, false);
+	else
+		kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
 }
 
 /**
@@ -1037,6 +1045,10 @@ void stage2_unmap_vm(struct kvm *kvm)
 	struct kvm_memory_slot *memslot;
 	int idx, bkt;
 
+	/* For realms this is handled by the RMM so nothing to do here */
+	if (kvm_is_realm(kvm))
+		return;
+
 	idx = srcu_read_lock(&kvm->srcu);
 	mmap_read_lock(current->mm);
 	write_lock(&kvm->mmu_lock);
@@ -1062,6 +1074,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 	if (kvm_is_realm(kvm) &&
 	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
 	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
+		kvm_stage2_unmap_range(mmu, 0, (~0ULL) & PAGE_MASK);
 		write_unlock(&kvm->mmu_lock);
 		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
 		return;
@@ -1428,6 +1441,71 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
 	return vma->vm_flags & VM_MTE_ALLOWED;
 }
 
+static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
+			 kvm_pfn_t pfn, unsigned long map_size,
+			 enum kvm_pgtable_prot prot,
+			 struct kvm_mmu_memory_cache *memcache)
+{
+	struct realm *realm = &kvm->arch.realm;
+	struct page *page = pfn_to_page(pfn);
+
+	if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
+		return -EFAULT;
+
+	if (!realm_is_addr_protected(realm, ipa))
+		return realm_map_non_secure(realm, ipa, page, map_size,
+					    memcache);
+
+	return realm_map_protected(realm, ipa, page, map_size, memcache);
+}
+
+static int private_memslot_fault(struct kvm_vcpu *vcpu,
+				 phys_addr_t fault_ipa,
+				 struct kvm_memory_slot *memslot)
+{
+	struct kvm *kvm = vcpu->kvm;
+	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
+	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
+	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
+	bool priv_exists = kvm_mem_is_private(kvm, gfn);
+	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
+	kvm_pfn_t pfn;
+	int ret;
+
+	if (priv_exists != is_priv_gfn) {
+		kvm_prepare_memory_fault_exit(vcpu,
+					      fault_ipa & ~gpa_stolen_mask,
+					      PAGE_SIZE,
+					      kvm_is_write_fault(vcpu),
+					      false, is_priv_gfn);
+
+		return 0;
+	}
+
+	if (!is_priv_gfn) {
+		/* Not a private mapping, handling normally */
+		return -EAGAIN;
+	}
+
+	ret = kvm_mmu_topup_memory_cache(memcache,
+					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
+	if (ret)
+		return ret;
+
+	ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, NULL);
+	if (ret)
+		return ret;
+
+	/* FIXME: Should be able to use bigger than PAGE_SIZE mappings */
+	ret = realm_map_ipa(kvm, fault_ipa, pfn, PAGE_SIZE, KVM_PGTABLE_PROT_W,
+			    memcache);
+	if (!ret)
+		return 1; /* Handled */
+
+	put_page(pfn_to_page(pfn));
+	return ret;
+}
+
 static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 			  struct kvm_s2_trans *nested,
 			  struct kvm_memory_slot *memslot, unsigned long hva,
@@ -1449,10 +1527,19 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	long vma_pagesize, fault_granule;
 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
 	struct kvm_pgtable *pgt;
+	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 
 	if (fault_is_perm)
 		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
 	write_fault = kvm_is_write_fault(vcpu);
+
+	/*
+	 * Realms cannot map protected pages read-only
+	 * FIXME: It should be possible to map unprotected pages read-only
+	 */
+	if (vcpu_is_rec(vcpu))
+		write_fault = true;
+
 	exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
 	VM_BUG_ON(write_fault && exec_fault);
 
@@ -1553,7 +1640,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
 		fault_ipa &= ~(vma_pagesize - 1);
 
-	gfn = ipa >> PAGE_SHIFT;
+	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
 	mte_allowed = kvm_vma_mte_allowed(vma);
 
 	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
@@ -1634,7 +1721,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * If we are not forced to use page mapping, check if we are
 	 * backed by a THP and thus use block mapping if possible.
 	 */
-	if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
+	/* FIXME: We shouldn't need to disable this for realms */
+	if (vma_pagesize == PAGE_SIZE && !(force_pte || device || kvm_is_realm(kvm))) {
 		if (fault_is_perm && fault_granule > PAGE_SIZE)
 			vma_pagesize = fault_granule;
 		else
@@ -1686,6 +1774,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		 */
 		prot &= ~KVM_NV_GUEST_MAP_SZ;
 		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
+	} else if (kvm_is_realm(kvm)) {
+		ret = realm_map_ipa(kvm, fault_ipa, pfn, vma_pagesize,
+				    prot, memcache);
 	} else {
 		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
 					     __pfn_to_phys(pfn), prot,
@@ -1744,6 +1835,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 	struct kvm_memory_slot *memslot;
 	unsigned long hva;
 	bool is_iabt, write_fault, writable;
+	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 	gfn_t gfn;
 	int ret, idx;
 
@@ -1834,8 +1926,15 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		nested = &nested_trans;
 	}
 
-	gfn = ipa >> PAGE_SHIFT;
+	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
+
+	if (kvm_slot_can_be_private(memslot)) {
+		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
+		if (ret != -EAGAIN)
+			goto out;
+	}
+
 	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
 	write_fault = kvm_is_write_fault(vcpu);
 	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
@@ -1879,6 +1978,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		 * of the page size.
 		 */
 		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
+		ipa &= ~gpa_stolen_mask;
 		ret = io_mem_abort(vcpu, ipa);
 		goto out_unlock;
 	}
@@ -1927,6 +2027,10 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 	if (!kvm->arch.mmu.pgt)
 		return false;
 
+	/* We don't support aging for Realms */
+	if (kvm_is_realm(kvm))
+		return true;
+
 	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
 						   range->start << PAGE_SHIFT,
 						   size, true);
@@ -1943,6 +2047,10 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 	if (!kvm->arch.mmu.pgt)
 		return false;
 
+	/* We don't support aging for Realms */
+	if (kvm_is_realm(kvm))
+		return true;
+
 	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
 						   range->start << PAGE_SHIFT,
 						   size, false);
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 2c4e28b457be..337b3dd1e00c 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -627,6 +627,181 @@ static int fold_rtt(struct realm *realm, unsigned long addr, int level)
 	return 0;
 }
 
+static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
+{
+	bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;
+
+	if (lpa2)
+		return rtt->desc & GENMASK(49, 12);
+	return rtt->desc & GENMASK(47, 12);
+}
+
+int realm_map_protected(struct realm *realm,
+			unsigned long base_ipa,
+			struct page *dst_page,
+			unsigned long map_size,
+			struct kvm_mmu_memory_cache *memcache)
+{
+	phys_addr_t dst_phys = page_to_phys(dst_page);
+	phys_addr_t rd = virt_to_phys(realm->rd);
+	unsigned long phys = dst_phys;
+	unsigned long ipa = base_ipa;
+	unsigned long size;
+	int map_level;
+	int ret = 0;
+
+	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
+		return -EINVAL;
+
+	switch (map_size) {
+	case PAGE_SIZE:
+		map_level = 3;
+		break;
+	case RME_L2_BLOCK_SIZE:
+		map_level = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (map_level < RME_RTT_MAX_LEVEL) {
+		/*
+		 * A temporary RTT is needed during the map, precreate it,
+		 * however if there is an error (e.g. missing parent tables)
+		 * this will be handled below.
+		 */
+		realm_create_rtt_levels(realm, ipa, map_level,
+					RME_RTT_MAX_LEVEL, memcache);
+	}
+
+	for (size = 0; size < map_size; size += PAGE_SIZE) {
+		if (rmi_granule_delegate(phys)) {
+			struct rtt_entry rtt;
+
+			/*
+			 * It's possible we raced with another VCPU on the same
+			 * fault. If the entry exists and matches then exit
+			 * early and assume the other VCPU will handle the
+			 * mapping.
+			 */
+			if (rmi_rtt_read_entry(rd, ipa, RME_RTT_MAX_LEVEL, &rtt))
+				goto err;
+
+			/*
+			 * FIXME: For a block mapping this could race at level
+			 * 2 or 3... currently we don't support block mappings
+			 */
+			if (WARN_ON((rtt.walk_level != RME_RTT_MAX_LEVEL ||
+				     rtt.state != RMI_ASSIGNED ||
+				     rtt_get_phys(realm, &rtt) != phys))) {
+				goto err;
+			}
+
+			return 0;
+		}
+
+		ret = rmi_data_create_unknown(rd, phys, ipa);
+
+		if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+			/* Create missing RTTs and retry */
+			int level = RMI_RETURN_INDEX(ret);
+
+			ret = realm_create_rtt_levels(realm, ipa, level,
+						      RME_RTT_MAX_LEVEL,
+						      memcache);
+			WARN_ON(ret);
+			if (ret)
+				goto err_undelegate;
+
+			ret = rmi_data_create_unknown(rd, phys, ipa);
+		}
+		WARN_ON(ret);
+
+		if (ret)
+			goto err_undelegate;
+
+		phys += PAGE_SIZE;
+		ipa += PAGE_SIZE;
+	}
+
+	if (map_size == RME_L2_BLOCK_SIZE)
+		ret = fold_rtt(realm, base_ipa, map_level);
+	if (WARN_ON(ret))
+		goto err;
+
+	return 0;
+
+err_undelegate:
+	if (WARN_ON(rmi_granule_undelegate(phys))) {
+		/* Page can't be returned to NS world so is lost */
+		get_page(phys_to_page(phys));
+	}
+err:
+	while (size > 0) {
+		unsigned long data, top;
+
+		phys -= PAGE_SIZE;
+		size -= PAGE_SIZE;
+		ipa -= PAGE_SIZE;
+
+		WARN_ON(rmi_data_destroy(rd, ipa, &data, &top));
+
+		if (WARN_ON(rmi_granule_undelegate(phys))) {
+			/* Page can't be returned to NS world so is lost */
+			get_page(phys_to_page(phys));
+		}
+	}
+	return -ENXIO;
+}
+
+int realm_map_non_secure(struct realm *realm,
+			 unsigned long ipa,
+			 struct page *page,
+			 unsigned long map_size,
+			 struct kvm_mmu_memory_cache *memcache)
+{
+	phys_addr_t rd = virt_to_phys(realm->rd);
+	int map_level;
+	int ret = 0;
+	unsigned long desc = page_to_phys(page) |
+			     PTE_S2_MEMATTR(MT_S2_FWB_NORMAL) |
+			     /* FIXME: Read+Write permissions for now */
+			     (3 << 6) |
+			     PTE_SHARED;
+
+	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
+		return -EINVAL;
+
+	switch (map_size) {
+	case PAGE_SIZE:
+		map_level = 3;
+		break;
+	case RME_L2_BLOCK_SIZE:
+		map_level = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
+
+	if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
+		/* Create missing RTTs and retry */
+		int level = RMI_RETURN_INDEX(ret);
+
+		ret = realm_create_rtt_levels(realm, ipa, level, map_level,
+					      memcache);
+		if (WARN_ON(ret))
+			return -ENXIO;
+
+		ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
+	}
+	if (WARN_ON(ret))
+		return -ENXIO;
+
+	return 0;
+}
+
 static int populate_par_region(struct kvm *kvm,
 			       phys_addr_t ipa_base,
 			       phys_addr_t ipa_end,
@@ -638,7 +813,6 @@ static int populate_par_region(struct kvm *kvm,
 	int idx;
 	phys_addr_t ipa;
 	int ret = 0;
-	struct page *tmp_page;
 	unsigned long data_flags = 0;
 
 	base_gfn = gpa_to_gfn(ipa_base);
@@ -660,9 +834,8 @@ static int populate_par_region(struct kvm *kvm,
 		goto out;
 	}
 
-	tmp_page = alloc_page(GFP_KERNEL);
-	if (!tmp_page) {
-		ret = -ENOMEM;
+	if (!kvm_slot_can_be_private(memslot)) {
+		ret = -EINVAL;
 		goto out;
 	}
 
@@ -729,28 +902,32 @@ static int populate_par_region(struct kvm *kvm,
 		for (offset = 0; offset < map_size && !ret;
 		     offset += PAGE_SIZE, page++) {
 			phys_addr_t page_ipa = ipa + offset;
+			kvm_pfn_t priv_pfn;
+			int order;
+
+			ret = kvm_gmem_get_pfn(kvm, memslot,
+					       page_ipa >> PAGE_SHIFT,
+					       &priv_pfn, &order);
+			if (ret)
+				break;
 
 			ret = realm_create_protected_data_page(realm, page_ipa,
-							       page, tmp_page,
-							       data_flags);
+							       pfn_to_page(priv_pfn),
+							       page, data_flags);
 		}
+
+		kvm_release_pfn_clean(pfn);
+
 		if (ret)
-			goto err_release_pfn;
+			break;
 
 		if (level == 2)
 			fold_rtt(realm, ipa, level);
 
 		ipa += map_size;
-		kvm_release_pfn_dirty(pfn);
-err_release_pfn:
-		if (ret) {
-			kvm_release_pfn_clean(pfn);
-			break;
-		}
 	}
 
 	mmap_read_unlock(current->mm);
-	__free_page(tmp_page);
 
 out:
 	srcu_read_unlock(&kvm->srcu, idx);
-- 
2.34.1

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> At runtime if the realm guest accesses memory which hasn't yet been
> mapped then KVM needs to either populate the region or fault the guest.
>
> For memory in the lower (protected) region of IPA a fresh page is
> provided to the RMM which will zero the contents. For memory in the
> upper (shared) region of IPA, the memory from the memslot is mapped
> into the realm VM non secure.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>  * Avoid leaking memory if failing to map it in the realm.
>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>  * Adapt to changes in previous patches.
>

....

> -	gfn = ipa >> PAGE_SHIFT;
> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
> +
> +	if (kvm_slot_can_be_private(memslot)) {
> +		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
> +		if (ret != -EAGAIN)
> +			goto out;
> +	}
>

Shouldn't this be s/fault_ipa/ipa ?

	ret = private_memslot_fault(vcpu, ipa, memslot);

-aneesh

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

On 22/08/2024 04:32, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> At runtime if the realm guest accesses memory which hasn't yet been
>> mapped then KVM needs to either populate the region or fault the guest.
>>
>> For memory in the lower (protected) region of IPA a fresh page is
>> provided to the RMM which will zero the contents. For memory in the
>> upper (shared) region of IPA, the memory from the memslot is mapped
>> into the realm VM non secure.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>  * Avoid leaking memory if failing to map it in the realm.
>>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>>  * Adapt to changes in previous patches.
>>
> 
> ....
> 
>> -	gfn = ipa >> PAGE_SHIFT;
>> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>> +
>> +	if (kvm_slot_can_be_private(memslot)) {
>> +		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
>> +		if (ret != -EAGAIN)
>> +			goto out;
>> +	}
>>
> 
> Shouldn't this be s/fault_ipa/ipa ?

Well they should both be the same unless we're in some scary parallel
universe where we have nested virtualisation *and* realms at the same
time (shudder!). But yes "ipa" would be more consistent so I'll change it!

Steve

> 	ret = private_memslot_fault(vcpu, ipa, memslot);
> 
> -aneesh

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> At runtime if the realm guest accesses memory which hasn't yet been
> mapped then KVM needs to either populate the region or fault the guest.
>
> For memory in the lower (protected) region of IPA a fresh page is
> provided to the RMM which will zero the contents. For memory in the
> upper (shared) region of IPA, the memory from the memslot is mapped
> into the realm VM non secure.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>  * Avoid leaking memory if failing to map it in the realm.
>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>  * Adapt to changes in previous patches.
> ---
>  arch/arm64/include/asm/kvm_emulate.h |  10 ++
>  arch/arm64/include/asm/kvm_rme.h     |  10 ++
>  arch/arm64/kvm/mmu.c                 | 120 +++++++++++++++-
>  arch/arm64/kvm/rme.c                 | 205 +++++++++++++++++++++++++--
>  4 files changed, 325 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 7430c77574e3..0b50572d3719 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -710,6 +710,16 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>  }
>  
> +static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
> +{
> +	if (kvm_is_realm(kvm)) {
> +		struct realm *realm = &kvm->arch.realm;
> +
> +		return BIT(realm->ia_bits - 1);
> +	}
> +	return 0;
> +}
> +
>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>  {
>  	if (static_branch_unlikely(&kvm_rme_is_available))
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index 0e44b20cfa48..c50854f44674 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -103,6 +103,16 @@ void kvm_realm_unmap_range(struct kvm *kvm,
>  			   unsigned long ipa,
>  			   u64 size,
>  			   bool unmap_private);
> +int realm_map_protected(struct realm *realm,
> +			unsigned long base_ipa,
> +			struct page *dst_page,
> +			unsigned long map_size,
> +			struct kvm_mmu_memory_cache *memcache);
> +int realm_map_non_secure(struct realm *realm,
> +			 unsigned long ipa,
> +			 struct page *page,
> +			 unsigned long map_size,
> +			 struct kvm_mmu_memory_cache *memcache);
>  int realm_set_ipa_state(struct kvm_vcpu *vcpu,
>  			unsigned long addr, unsigned long end,
>  			unsigned long ripas,
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 620d26810019..eb8b8d013f3e 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -325,8 +325,13 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
>  
>  	lockdep_assert_held_write(&kvm->mmu_lock);
>  	WARN_ON(size & ~PAGE_MASK);
> -	WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
> -				   may_block));
> +
> +	if (kvm_is_realm(kvm))
> +		kvm_realm_unmap_range(kvm, start, size, !only_shared);
> +	else
> +		WARN_ON(stage2_apply_range(mmu, start, end,
> +					   kvm_pgtable_stage2_unmap,
> +					   may_block));
>  }
>  
>  void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
> @@ -345,7 +350,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
>  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
>  	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
>  
> -	kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
> +	if (kvm_is_realm(kvm))
> +		kvm_realm_unmap_range(kvm, addr, end - addr, false);
> +	else
> +		kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>  }
>  
>  /**
> @@ -1037,6 +1045,10 @@ void stage2_unmap_vm(struct kvm *kvm)
>  	struct kvm_memory_slot *memslot;
>  	int idx, bkt;
>  
> +	/* For realms this is handled by the RMM so nothing to do here */
> +	if (kvm_is_realm(kvm))
> +		return;
> +
>  	idx = srcu_read_lock(&kvm->srcu);
>  	mmap_read_lock(current->mm);
>  	write_lock(&kvm->mmu_lock);
> @@ -1062,6 +1074,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>  	if (kvm_is_realm(kvm) &&
>  	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
>  	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
> +		kvm_stage2_unmap_range(mmu, 0, (~0ULL) & PAGE_MASK);
>  		write_unlock(&kvm->mmu_lock);
>  		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
>  		return;
> @@ -1428,6 +1441,71 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
>  	return vma->vm_flags & VM_MTE_ALLOWED;
>  }
>  
> +static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
> +			 kvm_pfn_t pfn, unsigned long map_size,
> +			 enum kvm_pgtable_prot prot,
> +			 struct kvm_mmu_memory_cache *memcache)
> +{
> +	struct realm *realm = &kvm->arch.realm;
> +	struct page *page = pfn_to_page(pfn);
> +
> +	if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
> +		return -EFAULT;
> +
> +	if (!realm_is_addr_protected(realm, ipa))
> +		return realm_map_non_secure(realm, ipa, page, map_size,
> +					    memcache);
> +
> +	return realm_map_protected(realm, ipa, page, map_size, memcache);
> +}
> +
> +static int private_memslot_fault(struct kvm_vcpu *vcpu,
> +				 phys_addr_t fault_ipa,
> +				 struct kvm_memory_slot *memslot)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
> +	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
> +	bool priv_exists = kvm_mem_is_private(kvm, gfn);
> +	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
> +	kvm_pfn_t pfn;
> +	int ret;
> +
> +	if (priv_exists != is_priv_gfn) {
> +		kvm_prepare_memory_fault_exit(vcpu,
> +					      fault_ipa & ~gpa_stolen_mask,
> +					      PAGE_SIZE,
> +					      kvm_is_write_fault(vcpu),
> +					      false, is_priv_gfn);
> +
> +		return 0;
> +	}
> +
> +	if (!is_priv_gfn) {
> +		/* Not a private mapping, handling normally */
> +		return -EAGAIN;
> +	}
>

Instead of that EAGAIN, it better to handle as below?

 arch/arm64/kvm/mmu.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 1eddbc7d7156..33ef95b5c94a 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1480,11 +1480,6 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
 		return 0;
 	}
 
-	if (!is_priv_gfn) {
-		/* Not a private mapping, handling normally */
-		return -EAGAIN;
-	}
-
 	ret = kvm_mmu_topup_memory_cache(memcache,
 					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
 	if (ret)
@@ -1925,12 +1920,25 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
 
-	if (kvm_slot_can_be_private(memslot)) {
-		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
-		if (ret != -EAGAIN)
+	if (kvm_slot_can_be_private(memslot) &&
+	    kvm_is_private_gpa(vcpu->kvm, ipa)) {
+		ret = private_memslot_fault(vcpu, ipa, memslot);
 			goto out;
 	}
+	/* attribute msimatch. shared access fault on a mem with private attribute */
+	if (kvm_mem_is_private(vcpu->kvm, gfn)) {
+		/* let VMM fixup the memory attribute */
+		kvm_prepare_memory_fault_exit(vcpu,
+					      kvm_gpa_from_fault(vcpu->kvm, ipa),
+					      PAGE_SIZE,
+					      kvm_is_write_fault(vcpu),
+					      false, false);
+
+		ret =  0;
+		goto out;
+	}
 
+	/* Slot can be be private, but fault addr is not, handle that as normal fault */
 	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
 	write_fault = kvm_is_write_fault(vcpu);
 	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
-- 
2.34.1





> +
> +	ret = kvm_mmu_topup_memory_cache(memcache,
> +					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
> +	if (ret)
> +		return ret;
> +
> +	ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, NULL);
> +	if (ret)
> +		return ret;
> +
> +	/* FIXME: Should be able to use bigger than PAGE_SIZE mappings */
> +	ret = realm_map_ipa(kvm, fault_ipa, pfn, PAGE_SIZE, KVM_PGTABLE_PROT_W,
> +			    memcache);
> +	if (!ret)
> +		return 1; /* Handled */
> +
> +	put_page(pfn_to_page(pfn));
> +	return ret;
> +}
> +
>  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  			  struct kvm_s2_trans *nested,
>  			  struct kvm_memory_slot *memslot, unsigned long hva,
> @@ -1449,10 +1527,19 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	long vma_pagesize, fault_granule;
>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
>  	struct kvm_pgtable *pgt;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  
>  	if (fault_is_perm)
>  		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
>  	write_fault = kvm_is_write_fault(vcpu);
> +
> +	/*
> +	 * Realms cannot map protected pages read-only
> +	 * FIXME: It should be possible to map unprotected pages read-only
> +	 */
> +	if (vcpu_is_rec(vcpu))
> +		write_fault = true;
> +
>  	exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
>  	VM_BUG_ON(write_fault && exec_fault);
>  
> @@ -1553,7 +1640,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
>  		fault_ipa &= ~(vma_pagesize - 1);
>  
> -	gfn = ipa >> PAGE_SHIFT;
> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>  	mte_allowed = kvm_vma_mte_allowed(vma);
>  
>  	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
> @@ -1634,7 +1721,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	 * If we are not forced to use page mapping, check if we are
>  	 * backed by a THP and thus use block mapping if possible.
>  	 */
> -	if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
> +	/* FIXME: We shouldn't need to disable this for realms */
> +	if (vma_pagesize == PAGE_SIZE && !(force_pte || device || kvm_is_realm(kvm))) {
>  		if (fault_is_perm && fault_granule > PAGE_SIZE)
>  			vma_pagesize = fault_granule;
>  		else
> @@ -1686,6 +1774,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  		 */
>  		prot &= ~KVM_NV_GUEST_MAP_SZ;
>  		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
> +	} else if (kvm_is_realm(kvm)) {
> +		ret = realm_map_ipa(kvm, fault_ipa, pfn, vma_pagesize,
> +				    prot, memcache);
>  	} else {
>  		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
>  					     __pfn_to_phys(pfn), prot,
> @@ -1744,6 +1835,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  	struct kvm_memory_slot *memslot;
>  	unsigned long hva;
>  	bool is_iabt, write_fault, writable;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  	gfn_t gfn;
>  	int ret, idx;
>  
> @@ -1834,8 +1926,15 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		nested = &nested_trans;
>  	}
>  
> -	gfn = ipa >> PAGE_SHIFT;
> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
> +
> +	if (kvm_slot_can_be_private(memslot)) {
> +		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
> +		if (ret != -EAGAIN)
> +			goto out;
> +	}
> +
>

Instead of referring this as stolen bits is it better to do

 arch/arm64/include/asm/kvm_emulate.h | 20 +++++++++++++++++---
 arch/arm64/kvm/mmu.c                 | 21 ++++++++-------------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 0b50572d3719..790412fd53b8 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -710,14 +710,28 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
 	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
 }
 
-static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
+static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t fault_addr)
 {
+	gpa_t addr_mask;
+
 	if (kvm_is_realm(kvm)) {
 		struct realm *realm = &kvm->arch.realm;
 
-		return BIT(realm->ia_bits - 1);
+		addr_mask = BIT(realm->ia_bits - 1);
+		/* clear shared bit and return */
+		return fault_addr & ~addr_mask;
 	}
-	return 0;
+	return fault_addr;
+}
+
+static inline bool kvm_is_private_gpa(struct kvm *kvm, phys_addr_t fault_addr)
+{
+	/*
+	 * For Realms, the shared address is an alias of the private GPA
+	 * with top bit set and we have a single address space. Thus if the
+	 * fault address matches the GPA, it is the private GPA
+	 */
+	return fault_addr == kvm_gpa_from_fault(kvm, fault_addr);
 }
 
 static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index eb8b8d013f3e..1eddbc7d7156 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1464,20 +1464,18 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
 				 struct kvm_memory_slot *memslot)
 {
 	struct kvm *kvm = vcpu->kvm;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
-	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
-	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
-	bool priv_exists = kvm_mem_is_private(kvm, gfn);
+	gfn_t gfn = kvm_gpa_from_fault(kvm, fault_ipa) >> PAGE_SHIFT;
 	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 	kvm_pfn_t pfn;
 	int ret;
 
-	if (priv_exists != is_priv_gfn) {
+	if (!kvm_mem_is_private(kvm, gfn)) {
+		/* let VMM fixup the memory attribute */
 		kvm_prepare_memory_fault_exit(vcpu,
-					      fault_ipa & ~gpa_stolen_mask,
+					      kvm_gpa_from_fault(kvm, fault_ipa),
 					      PAGE_SIZE,
 					      kvm_is_write_fault(vcpu),
-					      false, is_priv_gfn);
+					      false, true);
 
 		return 0;
 	}
@@ -1527,7 +1525,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	long vma_pagesize, fault_granule;
 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
 	struct kvm_pgtable *pgt;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 
 	if (fault_is_perm)
 		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
@@ -1640,7 +1637,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
 		fault_ipa &= ~(vma_pagesize - 1);
 
-	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
+	gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
 	mte_allowed = kvm_vma_mte_allowed(vma);
 
 	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
@@ -1835,7 +1832,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 	struct kvm_memory_slot *memslot;
 	unsigned long hva;
 	bool is_iabt, write_fault, writable;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 	gfn_t gfn;
 	int ret, idx;
 
@@ -1926,7 +1922,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		nested = &nested_trans;
 	}
 
-	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
+	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
 
 	if (kvm_slot_can_be_private(memslot)) {
@@ -1978,8 +1974,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		 * of the page size.
 		 */
 		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
-		ipa &= ~gpa_stolen_mask;
-		ret = io_mem_abort(vcpu, ipa);
+		ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
 		goto out_unlock;
 	}
 
-- 


>  	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
>  	write_fault = kvm_is_write_fault(vcpu);
>  	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
> @@ -1879,6 +1978,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		 * of the page size.
>  		 */
>  		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
> +		ipa &= ~gpa_stolen_mask;
>  		ret = io_mem_abort(vcpu, ipa);
>  		goto out_unlock;
>  	}
> @@ -1927,6 +2027,10 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
>  	if (!kvm->arch.mmu.pgt)
>  		return false;
>  
> +	/* We don't support aging for Realms */
> +	if (kvm_is_realm(kvm))
> +		return true;
> +
>  	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
>  						   range->start << PAGE_SHIFT,
>  						   size, true);
> @@ -1943,6 +2047,10 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
>  	if (!kvm->arch.mmu.pgt)
>  		return false;
>  
> +	/* We don't support aging for Realms */
> +	if (kvm_is_realm(kvm))
> +		return true;
> +
>  	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
>  						   range->start << PAGE_SHIFT,
>  						   size, false);


-aneesh

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

On 22/08/2024 04:50, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> At runtime if the realm guest accesses memory which hasn't yet been
>> mapped then KVM needs to either populate the region or fault the guest.
>>
>> For memory in the lower (protected) region of IPA a fresh page is
>> provided to the RMM which will zero the contents. For memory in the
>> upper (shared) region of IPA, the memory from the memslot is mapped
>> into the realm VM non secure.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>> Changes since v2:
>>  * Avoid leaking memory if failing to map it in the realm.
>>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>>  * Adapt to changes in previous patches.
>> ---
>>  arch/arm64/include/asm/kvm_emulate.h |  10 ++
>>  arch/arm64/include/asm/kvm_rme.h     |  10 ++
>>  arch/arm64/kvm/mmu.c                 | 120 +++++++++++++++-
>>  arch/arm64/kvm/rme.c                 | 205 +++++++++++++++++++++++++--
>>  4 files changed, 325 insertions(+), 20 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
>> index 7430c77574e3..0b50572d3719 100644
>> --- a/arch/arm64/include/asm/kvm_emulate.h
>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>> @@ -710,6 +710,16 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>>  }
>>  
>> +static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
>> +{
>> +	if (kvm_is_realm(kvm)) {
>> +		struct realm *realm = &kvm->arch.realm;
>> +
>> +		return BIT(realm->ia_bits - 1);
>> +	}
>> +	return 0;
>> +}
>> +
>>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>>  {
>>  	if (static_branch_unlikely(&kvm_rme_is_available))
>> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
>> index 0e44b20cfa48..c50854f44674 100644
>> --- a/arch/arm64/include/asm/kvm_rme.h
>> +++ b/arch/arm64/include/asm/kvm_rme.h
>> @@ -103,6 +103,16 @@ void kvm_realm_unmap_range(struct kvm *kvm,
>>  			   unsigned long ipa,
>>  			   u64 size,
>>  			   bool unmap_private);
>> +int realm_map_protected(struct realm *realm,
>> +			unsigned long base_ipa,
>> +			struct page *dst_page,
>> +			unsigned long map_size,
>> +			struct kvm_mmu_memory_cache *memcache);
>> +int realm_map_non_secure(struct realm *realm,
>> +			 unsigned long ipa,
>> +			 struct page *page,
>> +			 unsigned long map_size,
>> +			 struct kvm_mmu_memory_cache *memcache);
>>  int realm_set_ipa_state(struct kvm_vcpu *vcpu,
>>  			unsigned long addr, unsigned long end,
>>  			unsigned long ripas,
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 620d26810019..eb8b8d013f3e 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -325,8 +325,13 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
>>  
>>  	lockdep_assert_held_write(&kvm->mmu_lock);
>>  	WARN_ON(size & ~PAGE_MASK);
>> -	WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
>> -				   may_block));
>> +
>> +	if (kvm_is_realm(kvm))
>> +		kvm_realm_unmap_range(kvm, start, size, !only_shared);
>> +	else
>> +		WARN_ON(stage2_apply_range(mmu, start, end,
>> +					   kvm_pgtable_stage2_unmap,
>> +					   may_block));
>>  }
>>  
>>  void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
>> @@ -345,7 +350,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
>>  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
>>  	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
>>  
>> -	kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>> +	if (kvm_is_realm(kvm))
>> +		kvm_realm_unmap_range(kvm, addr, end - addr, false);
>> +	else
>> +		kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>>  }
>>  
>>  /**
>> @@ -1037,6 +1045,10 @@ void stage2_unmap_vm(struct kvm *kvm)
>>  	struct kvm_memory_slot *memslot;
>>  	int idx, bkt;
>>  
>> +	/* For realms this is handled by the RMM so nothing to do here */
>> +	if (kvm_is_realm(kvm))
>> +		return;
>> +
>>  	idx = srcu_read_lock(&kvm->srcu);
>>  	mmap_read_lock(current->mm);
>>  	write_lock(&kvm->mmu_lock);
>> @@ -1062,6 +1074,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>>  	if (kvm_is_realm(kvm) &&
>>  	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
>>  	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
>> +		kvm_stage2_unmap_range(mmu, 0, (~0ULL) & PAGE_MASK);
>>  		write_unlock(&kvm->mmu_lock);
>>  		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
>>  		return;
>> @@ -1428,6 +1441,71 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
>>  	return vma->vm_flags & VM_MTE_ALLOWED;
>>  }
>>  
>> +static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
>> +			 kvm_pfn_t pfn, unsigned long map_size,
>> +			 enum kvm_pgtable_prot prot,
>> +			 struct kvm_mmu_memory_cache *memcache)
>> +{
>> +	struct realm *realm = &kvm->arch.realm;
>> +	struct page *page = pfn_to_page(pfn);
>> +
>> +	if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
>> +		return -EFAULT;
>> +
>> +	if (!realm_is_addr_protected(realm, ipa))
>> +		return realm_map_non_secure(realm, ipa, page, map_size,
>> +					    memcache);
>> +
>> +	return realm_map_protected(realm, ipa, page, map_size, memcache);
>> +}
>> +
>> +static int private_memslot_fault(struct kvm_vcpu *vcpu,
>> +				 phys_addr_t fault_ipa,
>> +				 struct kvm_memory_slot *memslot)
>> +{
>> +	struct kvm *kvm = vcpu->kvm;
>> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
>> +	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>> +	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
>> +	bool priv_exists = kvm_mem_is_private(kvm, gfn);
>> +	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>> +	kvm_pfn_t pfn;
>> +	int ret;
>> +
>> +	if (priv_exists != is_priv_gfn) {
>> +		kvm_prepare_memory_fault_exit(vcpu,
>> +					      fault_ipa & ~gpa_stolen_mask,
>> +					      PAGE_SIZE,
>> +					      kvm_is_write_fault(vcpu),
>> +					      false, is_priv_gfn);
>> +
>> +		return 0;
>> +	}
>> +
>> +	if (!is_priv_gfn) {
>> +		/* Not a private mapping, handling normally */
>> +		return -EAGAIN;
>> +	}
>>
> 
> Instead of that EAGAIN, it better to handle as below?

I'm not finding the below easier to read.

>  arch/arm64/kvm/mmu.c | 24 ++++++++++++++++--------
>  1 file changed, 16 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 1eddbc7d7156..33ef95b5c94a 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1480,11 +1480,6 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>  		return 0;
>  	}
>  
> -	if (!is_priv_gfn) {
> -		/* Not a private mapping, handling normally */
> -		return -EAGAIN;
> -	}
> -
>  	ret = kvm_mmu_topup_memory_cache(memcache,
>  					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
>  	if (ret)
> @@ -1925,12 +1920,25 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>  
> -	if (kvm_slot_can_be_private(memslot)) {
> -		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
> -		if (ret != -EAGAIN)
> +	if (kvm_slot_can_be_private(memslot) &&
> +	    kvm_is_private_gpa(vcpu->kvm, ipa)) {

I presume kvm_is_private_gpa() is defined as something like:

static bool kvm_is_private_gpa(kvm, phys_addr_t ipa)
{
	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
	return  !((ipa & gpa_stolen_mask) == gpa_stolen_mask);
}

> +		ret = private_memslot_fault(vcpu, ipa, memslot);

So this handles the case in private_memslot_fault() where is_priv_gfn is 
true. So there's a little bit of simplification in 
private_memslot_fault().

>  			goto out;
>  	}
> +	/* attribute msimatch. shared access fault on a mem with private attribute */
> +	if (kvm_mem_is_private(vcpu->kvm, gfn)) {
> +		/* let VMM fixup the memory attribute */
> +		kvm_prepare_memory_fault_exit(vcpu,
> +					      kvm_gpa_from_fault(vcpu->kvm, ipa),
> +					      PAGE_SIZE,
> +					      kvm_is_write_fault(vcpu),
> +					      false, false);

And then we have to duplicate the code here for calling 
kvm_prepare_memory_fault_exit(). Which seems a bit ugly to me. Am I 
missing something? Your patch doesn't seem complete.

> +
> +		ret =  0;
> +		goto out;
> +	}
>  
> +	/* Slot can be be private, but fault addr is not, handle that as normal fault */
>  	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
>  	write_fault = kvm_is_write_fault(vcpu);
>  	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {


Note your email had a signature line "--" here which causes my email 
client to remove the rest of your reply - it's worth dropping that from 
the git output when sending diffs. I've attempted to include your
second diff below manually.

> Instead of referring this as stolen bits is it better to do
> 
>  arch/arm64/include/asm/kvm_emulate.h | 20 +++++++++++++++++---
>  arch/arm64/kvm/mmu.c                 | 21 ++++++++-------------
>  2 files changed, 25 insertions(+), 16 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 0b50572d3719..790412fd53b8 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -710,14 +710,28 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>  }
>  
> -static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
> +static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t fault_addr)
>  {
> +	gpa_t addr_mask;
> +
>  	if (kvm_is_realm(kvm)) {
>  		struct realm *realm = &kvm->arch.realm;
>  
> -		return BIT(realm->ia_bits - 1);
> +		addr_mask = BIT(realm->ia_bits - 1);
> +		/* clear shared bit and return */
> +		return fault_addr & ~addr_mask;
>  	}
> -	return 0;
> +	return fault_addr;
> +}
> +
> +static inline bool kvm_is_private_gpa(struct kvm *kvm, phys_addr_t fault_addr)
> +{
> +	/*
> +	 * For Realms, the shared address is an alias of the private GPA
> +	 * with top bit set and we have a single address space. Thus if the
> +	 * fault address matches the GPA, it is the private GPA
> +	 */
> +	return fault_addr == kvm_gpa_from_fault(kvm, fault_addr);
>  }

Ah, so here's the missing function from above.

>  
>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index eb8b8d013f3e..1eddbc7d7156 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1464,20 +1464,18 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>  				 struct kvm_memory_slot *memslot)
>  {
>  	struct kvm *kvm = vcpu->kvm;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
> -	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> -	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
> -	bool priv_exists = kvm_mem_is_private(kvm, gfn);
> +	gfn_t gfn = kvm_gpa_from_fault(kvm, fault_ipa) >> PAGE_SHIFT;
>  	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>  	kvm_pfn_t pfn;
>  	int ret;
>  
> -	if (priv_exists != is_priv_gfn) {
> +	if (!kvm_mem_is_private(kvm, gfn)) {
> +		/* let VMM fixup the memory attribute */
>  		kvm_prepare_memory_fault_exit(vcpu,
> -					      fault_ipa & ~gpa_stolen_mask,
> +					      kvm_gpa_from_fault(kvm, fault_ipa),
>  					      PAGE_SIZE,
>  					      kvm_is_write_fault(vcpu),
> -					      false, is_priv_gfn);
> +					      false, true);
>  
>  		return 0;
>  	}
> @@ -1527,7 +1525,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	long vma_pagesize, fault_granule;
>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
>  	struct kvm_pgtable *pgt;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  
>  	if (fault_is_perm)
>  		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
> @@ -1640,7 +1637,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
>  		fault_ipa &= ~(vma_pagesize - 1);
>  
> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
>  	mte_allowed = kvm_vma_mte_allowed(vma);
>  
>  	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
> @@ -1835,7 +1832,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  	struct kvm_memory_slot *memslot;
>  	unsigned long hva;
>  	bool is_iabt, write_fault, writable;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  	gfn_t gfn;
>  	int ret, idx;
>  
> @@ -1926,7 +1922,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		nested = &nested_trans;
>  	}
>  
> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>  
>  	if (kvm_slot_can_be_private(memslot)) {
> @@ -1978,8 +1974,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		 * of the page size.
>  		 */
>  		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
> -		ipa &= ~gpa_stolen_mask;
> -		ret = io_mem_abort(vcpu, ipa);
> +		ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
>  		goto out_unlock;
>  	}

I can see your point that kvm_gpa_from_fault() makes sense. I'm still
not convinced about the duplication of the kvm_prepare_memory_fault_exit()
call though.

How about the following (untested):

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index 0b50572d3719..fa03520d7933 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -710,14 +710,14 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
 	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
 }
 
-static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
+static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t fault_ipa)
 {
 	if (kvm_is_realm(kvm)) {
 		struct realm *realm = &kvm->arch.realm;
 
-		return BIT(realm->ia_bits - 1);
+		return fault_ipa & ~BIT(realm->ia_bits - 1);
 	}
-	return 0;
+	return fault_ipa;
 }
 
 static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index d7e8b0c4f2a3..c0a3054201a9 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1468,9 +1468,9 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
 				 struct kvm_memory_slot *memslot)
 {
 	struct kvm *kvm = vcpu->kvm;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
-	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
-	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
+	gpa_t gpa = kvm_gpa_from_fault(kvm, fault_ipa);
+	gfn_t gfn = gpa >> PAGE_SHIFT;
+	bool is_priv_gfn = (gpa == fault_ipa);
 	bool priv_exists = kvm_mem_is_private(kvm, gfn);
 	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 	kvm_pfn_t pfn;
@@ -1478,7 +1478,7 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
 
 	if (priv_exists != is_priv_gfn) {
 		kvm_prepare_memory_fault_exit(vcpu,
-					      fault_ipa & ~gpa_stolen_mask,
+					      gpa,
 					      PAGE_SIZE,
 					      kvm_is_write_fault(vcpu),
 					      false, is_priv_gfn);
@@ -1531,7 +1531,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	long vma_pagesize, fault_granule;
 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
 	struct kvm_pgtable *pgt;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 
 	if (fault_is_perm)
 		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
@@ -1648,7 +1647,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
 		fault_ipa &= ~(vma_pagesize - 1);
 
-	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
+	gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
 	mte_allowed = kvm_vma_mte_allowed(vma);
 
 	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
@@ -1843,7 +1842,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 	struct kvm_memory_slot *memslot;
 	unsigned long hva;
 	bool is_iabt, write_fault, writable;
-	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
 	gfn_t gfn;
 	int ret, idx;
 
@@ -1934,7 +1932,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		nested = &nested_trans;
 	}
 
-	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
+	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
 	memslot = gfn_to_memslot(vcpu->kvm, gfn);
 
 	if (kvm_slot_can_be_private(memslot)) {
@@ -1986,8 +1984,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		 * of the page size.
 		 */
 		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
-		ipa &= ~gpa_stolen_mask;
-		ret = io_mem_abort(vcpu, ipa);
+		ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
 		goto out_unlock;
 	}
 

Thanks,
Steve

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> On 22/08/2024 04:50, Aneesh Kumar K.V wrote:
>> Steven Price <steven.price@arm.com> writes:
>>
>>> At runtime if the realm guest accesses memory which hasn't yet been
>>> mapped then KVM needs to either populate the region or fault the guest.
>>>
>>> For memory in the lower (protected) region of IPA a fresh page is
>>> provided to the RMM which will zero the contents. For memory in the
>>> upper (shared) region of IPA, the memory from the memslot is mapped
>>> into the realm VM non secure.
>>>
>>> Signed-off-by: Steven Price <steven.price@arm.com>
>>> ---
>>> Changes since v2:
>>>  * Avoid leaking memory if failing to map it in the realm.
>>>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>>>  * Adapt to changes in previous patches.
>>> ---
>>>  arch/arm64/include/asm/kvm_emulate.h |  10 ++
>>>  arch/arm64/include/asm/kvm_rme.h     |  10 ++
>>>  arch/arm64/kvm/mmu.c                 | 120 +++++++++++++++-
>>>  arch/arm64/kvm/rme.c                 | 205 +++++++++++++++++++++++++--
>>>  4 files changed, 325 insertions(+), 20 deletions(-)
>>>
>>> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
>>> index 7430c77574e3..0b50572d3719 100644
>>> --- a/arch/arm64/include/asm/kvm_emulate.h
>>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>>> @@ -710,6 +710,16 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>>>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>>>  }
>>>
>>> +static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
>>> +{
>>> +	if (kvm_is_realm(kvm)) {
>>> +		struct realm *realm = &kvm->arch.realm;
>>> +
>>> +		return BIT(realm->ia_bits - 1);
>>> +	}
>>> +	return 0;
>>> +}
>>> +
>>>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>>>  {
>>>  	if (static_branch_unlikely(&kvm_rme_is_available))
>>> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
>>> index 0e44b20cfa48..c50854f44674 100644
>>> --- a/arch/arm64/include/asm/kvm_rme.h
>>> +++ b/arch/arm64/include/asm/kvm_rme.h
>>> @@ -103,6 +103,16 @@ void kvm_realm_unmap_range(struct kvm *kvm,
>>>  			   unsigned long ipa,
>>>  			   u64 size,
>>>  			   bool unmap_private);
>>> +int realm_map_protected(struct realm *realm,
>>> +			unsigned long base_ipa,
>>> +			struct page *dst_page,
>>> +			unsigned long map_size,
>>> +			struct kvm_mmu_memory_cache *memcache);
>>> +int realm_map_non_secure(struct realm *realm,
>>> +			 unsigned long ipa,
>>> +			 struct page *page,
>>> +			 unsigned long map_size,
>>> +			 struct kvm_mmu_memory_cache *memcache);
>>>  int realm_set_ipa_state(struct kvm_vcpu *vcpu,
>>>  			unsigned long addr, unsigned long end,
>>>  			unsigned long ripas,
>>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>>> index 620d26810019..eb8b8d013f3e 100644
>>> --- a/arch/arm64/kvm/mmu.c
>>> +++ b/arch/arm64/kvm/mmu.c
>>> @@ -325,8 +325,13 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
>>>
>>>  	lockdep_assert_held_write(&kvm->mmu_lock);
>>>  	WARN_ON(size & ~PAGE_MASK);
>>> -	WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
>>> -				   may_block));
>>> +
>>> +	if (kvm_is_realm(kvm))
>>> +		kvm_realm_unmap_range(kvm, start, size, !only_shared);
>>> +	else
>>> +		WARN_ON(stage2_apply_range(mmu, start, end,
>>> +					   kvm_pgtable_stage2_unmap,
>>> +					   may_block));
>>>  }
>>>
>>>  void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
>>> @@ -345,7 +350,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
>>>  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
>>>  	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
>>>
>>> -	kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>>> +	if (kvm_is_realm(kvm))
>>> +		kvm_realm_unmap_range(kvm, addr, end - addr, false);
>>> +	else
>>> +		kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>>>  }
>>>
>>>  /**
>>> @@ -1037,6 +1045,10 @@ void stage2_unmap_vm(struct kvm *kvm)
>>>  	struct kvm_memory_slot *memslot;
>>>  	int idx, bkt;
>>>
>>> +	/* For realms this is handled by the RMM so nothing to do here */
>>> +	if (kvm_is_realm(kvm))
>>> +		return;
>>> +
>>>  	idx = srcu_read_lock(&kvm->srcu);
>>>  	mmap_read_lock(current->mm);
>>>  	write_lock(&kvm->mmu_lock);
>>> @@ -1062,6 +1074,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>>>  	if (kvm_is_realm(kvm) &&
>>>  	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
>>>  	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
>>> +		kvm_stage2_unmap_range(mmu, 0, (~0ULL) & PAGE_MASK);
>>>  		write_unlock(&kvm->mmu_lock);
>>>  		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
>>>  		return;
>>> @@ -1428,6 +1441,71 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
>>>  	return vma->vm_flags & VM_MTE_ALLOWED;
>>>  }
>>>
>>> +static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
>>> +			 kvm_pfn_t pfn, unsigned long map_size,
>>> +			 enum kvm_pgtable_prot prot,
>>> +			 struct kvm_mmu_memory_cache *memcache)
>>> +{
>>> +	struct realm *realm = &kvm->arch.realm;
>>> +	struct page *page = pfn_to_page(pfn);
>>> +
>>> +	if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
>>> +		return -EFAULT;
>>> +
>>> +	if (!realm_is_addr_protected(realm, ipa))
>>> +		return realm_map_non_secure(realm, ipa, page, map_size,
>>> +					    memcache);
>>> +
>>> +	return realm_map_protected(realm, ipa, page, map_size, memcache);
>>> +}
>>> +
>>> +static int private_memslot_fault(struct kvm_vcpu *vcpu,
>>> +				 phys_addr_t fault_ipa,
>>> +				 struct kvm_memory_slot *memslot)
>>> +{
>>> +	struct kvm *kvm = vcpu->kvm;
>>> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
>>> +	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>>> +	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
>>> +	bool priv_exists = kvm_mem_is_private(kvm, gfn);
>>> +	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>>> +	kvm_pfn_t pfn;
>>> +	int ret;
>>> +
>>> +	if (priv_exists != is_priv_gfn) {
>>> +		kvm_prepare_memory_fault_exit(vcpu,
>>> +					      fault_ipa & ~gpa_stolen_mask,
>>> +					      PAGE_SIZE,
>>> +					      kvm_is_write_fault(vcpu),
>>> +					      false, is_priv_gfn);
>>> +
>>> +		return 0;
>>> +	}
>>> +
>>> +	if (!is_priv_gfn) {
>>> +		/* Not a private mapping, handling normally */
>>> +		return -EAGAIN;
>>> +	}
>>>
>>
>> Instead of that EAGAIN, it better to handle as below?
>
> I'm not finding the below easier to read.
>
>>  arch/arm64/kvm/mmu.c | 24 ++++++++++++++++--------
>>  1 file changed, 16 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index 1eddbc7d7156..33ef95b5c94a 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -1480,11 +1480,6 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>>  		return 0;
>>  	}
>>
>> -	if (!is_priv_gfn) {
>> -		/* Not a private mapping, handling normally */
>> -		return -EAGAIN;
>> -	}
>> -
>>  	ret = kvm_mmu_topup_memory_cache(memcache,
>>  					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
>>  	if (ret)
>> @@ -1925,12 +1920,25 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>>  	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
>>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>>
>> -	if (kvm_slot_can_be_private(memslot)) {
>> -		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
>> -		if (ret != -EAGAIN)
>> +	if (kvm_slot_can_be_private(memslot) &&
>> +	    kvm_is_private_gpa(vcpu->kvm, ipa)) {
>
> I presume kvm_is_private_gpa() is defined as something like:
>
> static bool kvm_is_private_gpa(kvm, phys_addr_t ipa)
> {
> 	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
> 	return  !((ipa & gpa_stolen_mask) == gpa_stolen_mask);
> }
>
>> +		ret = private_memslot_fault(vcpu, ipa, memslot);
>
> So this handles the case in private_memslot_fault() where is_priv_gfn is
> true. So there's a little bit of simplification in
> private_memslot_fault().
>
>>  			goto out;
>>  	}
>> +	/* attribute msimatch. shared access fault on a mem with private attribute */
>> +	if (kvm_mem_is_private(vcpu->kvm, gfn)) {
>> +		/* let VMM fixup the memory attribute */
>> +		kvm_prepare_memory_fault_exit(vcpu,
>> +					      kvm_gpa_from_fault(vcpu->kvm, ipa),
>> +					      PAGE_SIZE,
>> +					      kvm_is_write_fault(vcpu),
>> +					      false, false);
>
> And then we have to duplicate the code here for calling
> kvm_prepare_memory_fault_exit(). Which seems a bit ugly to me. Am I
> missing something? Your patch doesn't seem complete.
>


What confused me was I was looking at EAGAIN as retry access. But here
it is not a retry. It is an error condition for handling the fault as a
shared access fault. IMHO having that check in the caller makes it
simpler. ie,

if it is a private fault private_memslot_fault handle it with the fault
exit condition that indicates an attribute mismatch

if it is a shared fault the existing fault handling code handles it with
the fault exit condition indicating an attribute mismatch.

If you find the change not clean, can we rename the error to EINVAL?

>
>> +
>> +		ret =  0;
>> +		goto out;
>> +	}
>>
>> +	/* Slot can be be private, but fault addr is not, handle that as normal fault */
>>  	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
>>  	write_fault = kvm_is_write_fault(vcpu);
>>  	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
>
>
> Note your email had a signature line "--" here which causes my email
> client to remove the rest of your reply - it's worth dropping that from
> the git output when sending diffs. I've attempted to include your
> second diff below manually.
>
>> Instead of referring this as stolen bits is it better to do
>>
>>  arch/arm64/include/asm/kvm_emulate.h | 20 +++++++++++++++++---
>>  arch/arm64/kvm/mmu.c                 | 21 ++++++++-------------
>>  2 files changed, 25 insertions(+), 16 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
>> index 0b50572d3719..790412fd53b8 100644
>> --- a/arch/arm64/include/asm/kvm_emulate.h
>> +++ b/arch/arm64/include/asm/kvm_emulate.h
>> @@ -710,14 +710,28 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>>  }
>>
>> -static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
>> +static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t fault_addr)
>>  {
>> +	gpa_t addr_mask;
>> +
>>  	if (kvm_is_realm(kvm)) {
>>  		struct realm *realm = &kvm->arch.realm;
>>
>> -		return BIT(realm->ia_bits - 1);
>> +		addr_mask = BIT(realm->ia_bits - 1);
>> +		/* clear shared bit and return */
>> +		return fault_addr & ~addr_mask;
>>  	}
>> -	return 0;
>> +	return fault_addr;
>> +}
>> +
>> +static inline bool kvm_is_private_gpa(struct kvm *kvm, phys_addr_t fault_addr)
>> +{
>> +	/*
>> +	 * For Realms, the shared address is an alias of the private GPA
>> +	 * with top bit set and we have a single address space. Thus if the
>> +	 * fault address matches the GPA, it is the private GPA
>> +	 */
>> +	return fault_addr == kvm_gpa_from_fault(kvm, fault_addr);
>>  }
>
> Ah, so here's the missing function from above.
>
>>
>>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
>> index eb8b8d013f3e..1eddbc7d7156 100644
>> --- a/arch/arm64/kvm/mmu.c
>> +++ b/arch/arm64/kvm/mmu.c
>> @@ -1464,20 +1464,18 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>>  				 struct kvm_memory_slot *memslot)
>>  {
>>  	struct kvm *kvm = vcpu->kvm;
>> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
>> -	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>> -	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
>> -	bool priv_exists = kvm_mem_is_private(kvm, gfn);
>> +	gfn_t gfn = kvm_gpa_from_fault(kvm, fault_ipa) >> PAGE_SHIFT;
>>  	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>>  	kvm_pfn_t pfn;
>>  	int ret;
>>
>> -	if (priv_exists != is_priv_gfn) {
>> +	if (!kvm_mem_is_private(kvm, gfn)) {
>> +		/* let VMM fixup the memory attribute */
>>  		kvm_prepare_memory_fault_exit(vcpu,
>> -					      fault_ipa & ~gpa_stolen_mask,
>> +					      kvm_gpa_from_fault(kvm, fault_ipa),
>>  					      PAGE_SIZE,
>>  					      kvm_is_write_fault(vcpu),
>> -					      false, is_priv_gfn);
>> +					      false, true);
>>
>>  		return 0;
>>  	}
>> @@ -1527,7 +1525,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>>  	long vma_pagesize, fault_granule;
>>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
>>  	struct kvm_pgtable *pgt;
>> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>>
>>  	if (fault_is_perm)
>>  		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
>> @@ -1640,7 +1637,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>>  	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
>>  		fault_ipa &= ~(vma_pagesize - 1);
>>
>> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>> +	gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
>>  	mte_allowed = kvm_vma_mte_allowed(vma);
>>
>>  	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
>> @@ -1835,7 +1832,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>>  	struct kvm_memory_slot *memslot;
>>  	unsigned long hva;
>>  	bool is_iabt, write_fault, writable;
>> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>>  	gfn_t gfn;
>>  	int ret, idx;
>>
>> @@ -1926,7 +1922,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>>  		nested = &nested_trans;
>>  	}
>>
>> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>> +	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
>>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>>
>>  	if (kvm_slot_can_be_private(memslot)) {
>> @@ -1978,8 +1974,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>>  		 * of the page size.
>>  		 */
>>  		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
>> -		ipa &= ~gpa_stolen_mask;
>> -		ret = io_mem_abort(vcpu, ipa);
>> +		ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
>>  		goto out_unlock;
>>  	}
>
> I can see your point that kvm_gpa_from_fault() makes sense. I'm still
> not convinced about the duplication of the kvm_prepare_memory_fault_exit()
> call though.
>
> How about the following (untested):
>
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 0b50572d3719..fa03520d7933 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -710,14 +710,14 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>  }
>
> -static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
> +static inline gpa_t kvm_gpa_from_fault(struct kvm *kvm, phys_addr_t fault_ipa)
>  {
>  	if (kvm_is_realm(kvm)) {
>  		struct realm *realm = &kvm->arch.realm;
>
> -		return BIT(realm->ia_bits - 1);
> +		return fault_ipa & ~BIT(realm->ia_bits - 1);
>  	}
> -	return 0;
> +	return fault_ipa;
>  }
>
>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index d7e8b0c4f2a3..c0a3054201a9 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -1468,9 +1468,9 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>  				 struct kvm_memory_slot *memslot)
>  {
>  	struct kvm *kvm = vcpu->kvm;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
> -	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> -	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
> +	gpa_t gpa = kvm_gpa_from_fault(kvm, fault_ipa);
> +	gfn_t gfn = gpa >> PAGE_SHIFT;
> +	bool is_priv_gfn = (gpa == fault_ipa);
>  	bool priv_exists = kvm_mem_is_private(kvm, gfn);
>  	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>  	kvm_pfn_t pfn;
> @@ -1478,7 +1478,7 @@ static int private_memslot_fault(struct kvm_vcpu *vcpu,
>
>  	if (priv_exists != is_priv_gfn) {
>

Can we also have a helper with document for this?

static inline bool kvm_is_private_gpa(struct kvm *kvm, phys_addr_t fault_addr)
{
	/*
	 * For Realms, the shared address is an alias of the private GPA
	 * with top bit set and we have a single address space. Thus if the
	 * fault address matches the GPA, it is the private GPA
	 */
	return fault_addr == kvm_gpa_from_fault(kvm, fault_addr);
}


>  		kvm_prepare_memory_fault_exit(vcpu,
> -					      fault_ipa & ~gpa_stolen_mask,
> +					      gpa,
>  					      PAGE_SIZE,
>  					      kvm_is_write_fault(vcpu),
>  					      false, is_priv_gfn);
> @@ -1531,7 +1531,6 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	long vma_pagesize, fault_granule;
>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
>  	struct kvm_pgtable *pgt;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>
>  	if (fault_is_perm)
>  		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
> @@ -1648,7 +1647,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
>  		fault_ipa &= ~(vma_pagesize - 1);
>
> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	gfn = kvm_gpa_from_fault(kvm, ipa) >> PAGE_SHIFT;
>  	mte_allowed = kvm_vma_mte_allowed(vma);
>
>  	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
> @@ -1843,7 +1842,6 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  	struct kvm_memory_slot *memslot;
>  	unsigned long hva;
>  	bool is_iabt, write_fault, writable;
> -	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  	gfn_t gfn;
>  	int ret, idx;
>
> @@ -1934,7 +1932,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		nested = &nested_trans;
>  	}
>
> -	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	gfn = kvm_gpa_from_fault(vcpu->kvm, ipa) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>
>  	if (kvm_slot_can_be_private(memslot)) {
> @@ -1986,8 +1984,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		 * of the page size.
>  		 */
>  		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
> -		ipa &= ~gpa_stolen_mask;
> -		ret = io_mem_abort(vcpu, ipa);
> +		ret = io_mem_abort(vcpu, kvm_gpa_from_fault(vcpu->kvm, ipa));
>  		goto out_unlock;
>  	}
>
>
> Thanks,
> Steve

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Matias Ezequiel Vara Larsen]

Hello Steven, 

On Wed, Aug 21, 2024 at 04:38:22PM +0100, Steven Price wrote:
> At runtime if the realm guest accesses memory which hasn't yet been
> mapped then KVM needs to either populate the region or fault the guest.
> 
> For memory in the lower (protected) region of IPA a fresh page is
> provided to the RMM which will zero the contents. For memory in the
> upper (shared) region of IPA, the memory from the memslot is mapped
> into the realm VM non secure.
> 
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
> Changes since v2:
>  * Avoid leaking memory if failing to map it in the realm.
>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>  * Adapt to changes in previous patches.
> ---
>  arch/arm64/include/asm/kvm_emulate.h |  10 ++
>  arch/arm64/include/asm/kvm_rme.h     |  10 ++
>  arch/arm64/kvm/mmu.c                 | 120 +++++++++++++++-
>  arch/arm64/kvm/rme.c                 | 205 +++++++++++++++++++++++++--
>  4 files changed, 325 insertions(+), 20 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
> index 7430c77574e3..0b50572d3719 100644
> --- a/arch/arm64/include/asm/kvm_emulate.h
> +++ b/arch/arm64/include/asm/kvm_emulate.h
> @@ -710,6 +710,16 @@ static inline bool kvm_realm_is_created(struct kvm *kvm)
>  	return kvm_is_realm(kvm) && kvm_realm_state(kvm) != REALM_STATE_NONE;
>  }
>  
> +static inline gpa_t kvm_gpa_stolen_bits(struct kvm *kvm)
> +{
> +	if (kvm_is_realm(kvm)) {
> +		struct realm *realm = &kvm->arch.realm;
> +
> +		return BIT(realm->ia_bits - 1);
> +	}
> +	return 0;
> +}
> +
>  static inline bool vcpu_is_rec(struct kvm_vcpu *vcpu)
>  {
>  	if (static_branch_unlikely(&kvm_rme_is_available))
> diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
> index 0e44b20cfa48..c50854f44674 100644
> --- a/arch/arm64/include/asm/kvm_rme.h
> +++ b/arch/arm64/include/asm/kvm_rme.h
> @@ -103,6 +103,16 @@ void kvm_realm_unmap_range(struct kvm *kvm,
>  			   unsigned long ipa,
>  			   u64 size,
>  			   bool unmap_private);
> +int realm_map_protected(struct realm *realm,
> +			unsigned long base_ipa,
> +			struct page *dst_page,
> +			unsigned long map_size,
> +			struct kvm_mmu_memory_cache *memcache);
> +int realm_map_non_secure(struct realm *realm,
> +			 unsigned long ipa,
> +			 struct page *page,
> +			 unsigned long map_size,
> +			 struct kvm_mmu_memory_cache *memcache);
>  int realm_set_ipa_state(struct kvm_vcpu *vcpu,
>  			unsigned long addr, unsigned long end,
>  			unsigned long ripas,
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 620d26810019..eb8b8d013f3e 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -325,8 +325,13 @@ static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64
>  
>  	lockdep_assert_held_write(&kvm->mmu_lock);
>  	WARN_ON(size & ~PAGE_MASK);
> -	WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
> -				   may_block));
> +
> +	if (kvm_is_realm(kvm))
> +		kvm_realm_unmap_range(kvm, start, size, !only_shared);
> +	else
> +		WARN_ON(stage2_apply_range(mmu, start, end,
> +					   kvm_pgtable_stage2_unmap,
> +					   may_block));
>  }
>  
>  void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
> @@ -345,7 +350,10 @@ static void stage2_flush_memslot(struct kvm *kvm,
>  	phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
>  	phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
>  
> -	kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
> +	if (kvm_is_realm(kvm))
> +		kvm_realm_unmap_range(kvm, addr, end - addr, false);
> +	else
> +		kvm_stage2_flush_range(&kvm->arch.mmu, addr, end);
>  }
>  
>  /**
> @@ -1037,6 +1045,10 @@ void stage2_unmap_vm(struct kvm *kvm)
>  	struct kvm_memory_slot *memslot;
>  	int idx, bkt;
>  
> +	/* For realms this is handled by the RMM so nothing to do here */
> +	if (kvm_is_realm(kvm))
> +		return;
> +
>  	idx = srcu_read_lock(&kvm->srcu);
>  	mmap_read_lock(current->mm);
>  	write_lock(&kvm->mmu_lock);
> @@ -1062,6 +1074,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
>  	if (kvm_is_realm(kvm) &&
>  	    (kvm_realm_state(kvm) != REALM_STATE_DEAD &&
>  	     kvm_realm_state(kvm) != REALM_STATE_NONE)) {
> +		kvm_stage2_unmap_range(mmu, 0, (~0ULL) & PAGE_MASK);
>  		write_unlock(&kvm->mmu_lock);
>  		kvm_realm_destroy_rtts(kvm, pgt->ia_bits);
>  		return;
> @@ -1428,6 +1441,71 @@ static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
>  	return vma->vm_flags & VM_MTE_ALLOWED;
>  }
>  
> +static int realm_map_ipa(struct kvm *kvm, phys_addr_t ipa,
> +			 kvm_pfn_t pfn, unsigned long map_size,
> +			 enum kvm_pgtable_prot prot,
> +			 struct kvm_mmu_memory_cache *memcache)
> +{
> +	struct realm *realm = &kvm->arch.realm;
> +	struct page *page = pfn_to_page(pfn);
> +
> +	if (WARN_ON(!(prot & KVM_PGTABLE_PROT_W)))
> +		return -EFAULT;
> +
> +	if (!realm_is_addr_protected(realm, ipa))
> +		return realm_map_non_secure(realm, ipa, page, map_size,
> +					    memcache);
> +
> +	return realm_map_protected(realm, ipa, page, map_size, memcache);
> +}
> +
> +static int private_memslot_fault(struct kvm_vcpu *vcpu,
> +				 phys_addr_t fault_ipa,
> +				 struct kvm_memory_slot *memslot)
> +{
> +	struct kvm *kvm = vcpu->kvm;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
> +	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
> +	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
> +	bool priv_exists = kvm_mem_is_private(kvm, gfn);
> +	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
> +	kvm_pfn_t pfn;
> +	int ret;
> +
> +	if (priv_exists != is_priv_gfn) {
> +		kvm_prepare_memory_fault_exit(vcpu,
> +					      fault_ipa & ~gpa_stolen_mask,
> +					      PAGE_SIZE,
> +					      kvm_is_write_fault(vcpu),
> +					      false, is_priv_gfn);
> +
> +		return 0;
> +	}

If I understand correctly, `kvm_prepare_memory_fault_exit()` ends up
returning to the VMM with the KVM_EXIT_MEMORY_FAULT exit reason. The
documentation says (https://docs.kernel.org/virt/kvm/api.html#kvm-run):

"Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that
it accompanies a return code of ‘-1’, not ‘0’! errno will always be set
to EFAULT or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT,
userspace should assume kvm_run.exit_reason is stale/undefined for all
other error numbers."

Shall the return code be different for KVM_EXIT_MEMORY_FAULT?

Thanks, Matias.

> +
> +	if (!is_priv_gfn) {
> +		/* Not a private mapping, handling normally */
> +		return -EAGAIN;
> +	}
> +
> +	ret = kvm_mmu_topup_memory_cache(memcache,
> +					 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
> +	if (ret)
> +		return ret;
> +
> +	ret = kvm_gmem_get_pfn(kvm, memslot, gfn, &pfn, NULL);
> +	if (ret)
> +		return ret;
> +
> +	/* FIXME: Should be able to use bigger than PAGE_SIZE mappings */
> +	ret = realm_map_ipa(kvm, fault_ipa, pfn, PAGE_SIZE, KVM_PGTABLE_PROT_W,
> +			    memcache);
> +	if (!ret)
> +		return 1; /* Handled */
> +
> +	put_page(pfn_to_page(pfn));
> +	return ret;
> +}
> +
>  static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  			  struct kvm_s2_trans *nested,
>  			  struct kvm_memory_slot *memslot, unsigned long hva,
> @@ -1449,10 +1527,19 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	long vma_pagesize, fault_granule;
>  	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
>  	struct kvm_pgtable *pgt;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  
>  	if (fault_is_perm)
>  		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
>  	write_fault = kvm_is_write_fault(vcpu);
> +
> +	/*
> +	 * Realms cannot map protected pages read-only
> +	 * FIXME: It should be possible to map unprotected pages read-only
> +	 */
> +	if (vcpu_is_rec(vcpu))
> +		write_fault = true;
> +
>  	exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
>  	VM_BUG_ON(write_fault && exec_fault);
>  
> @@ -1553,7 +1640,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
>  		fault_ipa &= ~(vma_pagesize - 1);
>  
> -	gfn = ipa >> PAGE_SHIFT;
> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>  	mte_allowed = kvm_vma_mte_allowed(vma);
>  
>  	vfio_allow_any_uc = vma->vm_flags & VM_ALLOW_ANY_UNCACHED;
> @@ -1634,7 +1721,8 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  	 * If we are not forced to use page mapping, check if we are
>  	 * backed by a THP and thus use block mapping if possible.
>  	 */
> -	if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
> +	/* FIXME: We shouldn't need to disable this for realms */
> +	if (vma_pagesize == PAGE_SIZE && !(force_pte || device || kvm_is_realm(kvm))) {
>  		if (fault_is_perm && fault_granule > PAGE_SIZE)
>  			vma_pagesize = fault_granule;
>  		else
> @@ -1686,6 +1774,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
>  		 */
>  		prot &= ~KVM_NV_GUEST_MAP_SZ;
>  		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
> +	} else if (kvm_is_realm(kvm)) {
> +		ret = realm_map_ipa(kvm, fault_ipa, pfn, vma_pagesize,
> +				    prot, memcache);
>  	} else {
>  		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
>  					     __pfn_to_phys(pfn), prot,
> @@ -1744,6 +1835,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  	struct kvm_memory_slot *memslot;
>  	unsigned long hva;
>  	bool is_iabt, write_fault, writable;
> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(vcpu->kvm);
>  	gfn_t gfn;
>  	int ret, idx;
>  
> @@ -1834,8 +1926,15 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		nested = &nested_trans;
>  	}
>  
> -	gfn = ipa >> PAGE_SHIFT;
> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
> +
> +	if (kvm_slot_can_be_private(memslot)) {
> +		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
> +		if (ret != -EAGAIN)
> +			goto out;
> +	}
> +
>  	hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
>  	write_fault = kvm_is_write_fault(vcpu);
>  	if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
> @@ -1879,6 +1978,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
>  		 * of the page size.
>  		 */
>  		ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
> +		ipa &= ~gpa_stolen_mask;
>  		ret = io_mem_abort(vcpu, ipa);
>  		goto out_unlock;
>  	}
> @@ -1927,6 +2027,10 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
>  	if (!kvm->arch.mmu.pgt)
>  		return false;
>  
> +	/* We don't support aging for Realms */
> +	if (kvm_is_realm(kvm))
> +		return true;
> +
>  	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
>  						   range->start << PAGE_SHIFT,
>  						   size, true);
> @@ -1943,6 +2047,10 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
>  	if (!kvm->arch.mmu.pgt)
>  		return false;
>  
> +	/* We don't support aging for Realms */
> +	if (kvm_is_realm(kvm))
> +		return true;
> +
>  	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
>  						   range->start << PAGE_SHIFT,
>  						   size, false);
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> index 2c4e28b457be..337b3dd1e00c 100644
> --- a/arch/arm64/kvm/rme.c
> +++ b/arch/arm64/kvm/rme.c
> @@ -627,6 +627,181 @@ static int fold_rtt(struct realm *realm, unsigned long addr, int level)
>  	return 0;
>  }
>  
> +static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
> +{
> +	bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;
> +
> +	if (lpa2)
> +		return rtt->desc & GENMASK(49, 12);
> +	return rtt->desc & GENMASK(47, 12);
> +}
> +
> +int realm_map_protected(struct realm *realm,
> +			unsigned long base_ipa,
> +			struct page *dst_page,
> +			unsigned long map_size,
> +			struct kvm_mmu_memory_cache *memcache)
> +{
> +	phys_addr_t dst_phys = page_to_phys(dst_page);
> +	phys_addr_t rd = virt_to_phys(realm->rd);
> +	unsigned long phys = dst_phys;
> +	unsigned long ipa = base_ipa;
> +	unsigned long size;
> +	int map_level;
> +	int ret = 0;
> +
> +	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
> +		return -EINVAL;
> +
> +	switch (map_size) {
> +	case PAGE_SIZE:
> +		map_level = 3;
> +		break;
> +	case RME_L2_BLOCK_SIZE:
> +		map_level = 2;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (map_level < RME_RTT_MAX_LEVEL) {
> +		/*
> +		 * A temporary RTT is needed during the map, precreate it,
> +		 * however if there is an error (e.g. missing parent tables)
> +		 * this will be handled below.
> +		 */
> +		realm_create_rtt_levels(realm, ipa, map_level,
> +					RME_RTT_MAX_LEVEL, memcache);
> +	}
> +
> +	for (size = 0; size < map_size; size += PAGE_SIZE) {
> +		if (rmi_granule_delegate(phys)) {
> +			struct rtt_entry rtt;
> +
> +			/*
> +			 * It's possible we raced with another VCPU on the same
> +			 * fault. If the entry exists and matches then exit
> +			 * early and assume the other VCPU will handle the
> +			 * mapping.
> +			 */
> +			if (rmi_rtt_read_entry(rd, ipa, RME_RTT_MAX_LEVEL, &rtt))
> +				goto err;
> +
> +			/*
> +			 * FIXME: For a block mapping this could race at level
> +			 * 2 or 3... currently we don't support block mappings
> +			 */
> +			if (WARN_ON((rtt.walk_level != RME_RTT_MAX_LEVEL ||
> +				     rtt.state != RMI_ASSIGNED ||
> +				     rtt_get_phys(realm, &rtt) != phys))) {
> +				goto err;
> +			}
> +
> +			return 0;
> +		}
> +
> +		ret = rmi_data_create_unknown(rd, phys, ipa);
> +
> +		if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
> +			/* Create missing RTTs and retry */
> +			int level = RMI_RETURN_INDEX(ret);
> +
> +			ret = realm_create_rtt_levels(realm, ipa, level,
> +						      RME_RTT_MAX_LEVEL,
> +						      memcache);
> +			WARN_ON(ret);
> +			if (ret)
> +				goto err_undelegate;
> +
> +			ret = rmi_data_create_unknown(rd, phys, ipa);
> +		}
> +		WARN_ON(ret);
> +
> +		if (ret)
> +			goto err_undelegate;
> +
> +		phys += PAGE_SIZE;
> +		ipa += PAGE_SIZE;
> +	}
> +
> +	if (map_size == RME_L2_BLOCK_SIZE)
> +		ret = fold_rtt(realm, base_ipa, map_level);
> +	if (WARN_ON(ret))
> +		goto err;
> +
> +	return 0;
> +
> +err_undelegate:
> +	if (WARN_ON(rmi_granule_undelegate(phys))) {
> +		/* Page can't be returned to NS world so is lost */
> +		get_page(phys_to_page(phys));
> +	}
> +err:
> +	while (size > 0) {
> +		unsigned long data, top;
> +
> +		phys -= PAGE_SIZE;
> +		size -= PAGE_SIZE;
> +		ipa -= PAGE_SIZE;
> +
> +		WARN_ON(rmi_data_destroy(rd, ipa, &data, &top));
> +
> +		if (WARN_ON(rmi_granule_undelegate(phys))) {
> +			/* Page can't be returned to NS world so is lost */
> +			get_page(phys_to_page(phys));
> +		}
> +	}
> +	return -ENXIO;
> +}
> +
> +int realm_map_non_secure(struct realm *realm,
> +			 unsigned long ipa,
> +			 struct page *page,
> +			 unsigned long map_size,
> +			 struct kvm_mmu_memory_cache *memcache)
> +{
> +	phys_addr_t rd = virt_to_phys(realm->rd);
> +	int map_level;
> +	int ret = 0;
> +	unsigned long desc = page_to_phys(page) |
> +			     PTE_S2_MEMATTR(MT_S2_FWB_NORMAL) |
> +			     /* FIXME: Read+Write permissions for now */
> +			     (3 << 6) |
> +			     PTE_SHARED;
> +
> +	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
> +		return -EINVAL;
> +
> +	switch (map_size) {
> +	case PAGE_SIZE:
> +		map_level = 3;
> +		break;
> +	case RME_L2_BLOCK_SIZE:
> +		map_level = 2;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
> +
> +	if (RMI_RETURN_STATUS(ret) == RMI_ERROR_RTT) {
> +		/* Create missing RTTs and retry */
> +		int level = RMI_RETURN_INDEX(ret);
> +
> +		ret = realm_create_rtt_levels(realm, ipa, level, map_level,
> +					      memcache);
> +		if (WARN_ON(ret))
> +			return -ENXIO;
> +
> +		ret = rmi_rtt_map_unprotected(rd, ipa, map_level, desc);
> +	}
> +	if (WARN_ON(ret))
> +		return -ENXIO;
> +
> +	return 0;
> +}
> +
>  static int populate_par_region(struct kvm *kvm,
>  			       phys_addr_t ipa_base,
>  			       phys_addr_t ipa_end,
> @@ -638,7 +813,6 @@ static int populate_par_region(struct kvm *kvm,
>  	int idx;
>  	phys_addr_t ipa;
>  	int ret = 0;
> -	struct page *tmp_page;
>  	unsigned long data_flags = 0;
>  
>  	base_gfn = gpa_to_gfn(ipa_base);
> @@ -660,9 +834,8 @@ static int populate_par_region(struct kvm *kvm,
>  		goto out;
>  	}
>  
> -	tmp_page = alloc_page(GFP_KERNEL);
> -	if (!tmp_page) {
> -		ret = -ENOMEM;
> +	if (!kvm_slot_can_be_private(memslot)) {
> +		ret = -EINVAL;
>  		goto out;
>  	}
>  
> @@ -729,28 +902,32 @@ static int populate_par_region(struct kvm *kvm,
>  		for (offset = 0; offset < map_size && !ret;
>  		     offset += PAGE_SIZE, page++) {
>  			phys_addr_t page_ipa = ipa + offset;
> +			kvm_pfn_t priv_pfn;
> +			int order;
> +
> +			ret = kvm_gmem_get_pfn(kvm, memslot,
> +					       page_ipa >> PAGE_SHIFT,
> +					       &priv_pfn, &order);
> +			if (ret)
> +				break;
>  
>  			ret = realm_create_protected_data_page(realm, page_ipa,
> -							       page, tmp_page,
> -							       data_flags);
> +							       pfn_to_page(priv_pfn),
> +							       page, data_flags);
>  		}
> +
> +		kvm_release_pfn_clean(pfn);
> +
>  		if (ret)
> -			goto err_release_pfn;
> +			break;
>  
>  		if (level == 2)
>  			fold_rtt(realm, ipa, level);
>  
>  		ipa += map_size;
> -		kvm_release_pfn_dirty(pfn);
> -err_release_pfn:
> -		if (ret) {
> -			kvm_release_pfn_clean(pfn);
> -			break;
> -		}
>  	}
>  
>  	mmap_read_unlock(current->mm);
> -	__free_page(tmp_page);
>  
>  out:
>  	srcu_read_unlock(&kvm->srcu, idx);
> -- 
> 2.34.1
> 
> 

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

On 02/09/2024 14:25, Matias Ezequiel Vara Larsen wrote:
> Hello Steven, 
> 
> On Wed, Aug 21, 2024 at 04:38:22PM +0100, Steven Price wrote:

...

>> +static int private_memslot_fault(struct kvm_vcpu *vcpu,
>> +				 phys_addr_t fault_ipa,
>> +				 struct kvm_memory_slot *memslot)
>> +{
>> +	struct kvm *kvm = vcpu->kvm;
>> +	gpa_t gpa_stolen_mask = kvm_gpa_stolen_bits(kvm);
>> +	gfn_t gfn = (fault_ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>> +	bool is_priv_gfn = !((fault_ipa & gpa_stolen_mask) == gpa_stolen_mask);
>> +	bool priv_exists = kvm_mem_is_private(kvm, gfn);
>> +	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
>> +	kvm_pfn_t pfn;
>> +	int ret;
>> +
>> +	if (priv_exists != is_priv_gfn) {
>> +		kvm_prepare_memory_fault_exit(vcpu,
>> +					      fault_ipa & ~gpa_stolen_mask,
>> +					      PAGE_SIZE,
>> +					      kvm_is_write_fault(vcpu),
>> +					      false, is_priv_gfn);
>> +
>> +		return 0;
>> +	}
> 
> If I understand correctly, `kvm_prepare_memory_fault_exit()` ends up
> returning to the VMM with the KVM_EXIT_MEMORY_FAULT exit reason. The
> documentation says (https://docs.kernel.org/virt/kvm/api.html#kvm-run):
> 
> "Note! KVM_EXIT_MEMORY_FAULT is unique among all KVM exit reasons in that
> it accompanies a return code of ‘-1’, not ‘0’! errno will always be set
> to EFAULT or EHWPOISON when KVM exits with KVM_EXIT_MEMORY_FAULT,
> userspace should assume kvm_run.exit_reason is stale/undefined for all
> other error numbers."
> 
> Shall the return code be different for KVM_EXIT_MEMORY_FAULT?
> 
> Thanks, Matias.

Ah, good spot - I've no idea why KVM_EXIT_MEMORY_FAULT is special in
this regard, but yes I guess we should be returning -EFAULT here.

Thanks,
Steve

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Jean-Philippe Brucker]

On Wed, Aug 21, 2024 at 04:38:22PM +0100, Steven Price wrote:
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> index 2c4e28b457be..337b3dd1e00c 100644
> --- a/arch/arm64/kvm/rme.c
> +++ b/arch/arm64/kvm/rme.c
> @@ -627,6 +627,181 @@ static int fold_rtt(struct realm *realm, unsigned long addr, int level)
>  	return 0;
>  }
>  
> +static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
> +{
> +	bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;

At this point realm->params is NULL, cleared by kvm_create_realm()

Thanks,
Jean

> +
> +	if (lpa2)
> +		return rtt->desc & GENMASK(49, 12);
> +	return rtt->desc & GENMASK(47, 12);
> +}
> +
> +int realm_map_protected(struct realm *realm,
> +			unsigned long base_ipa,
> +			struct page *dst_page,
> +			unsigned long map_size,
> +			struct kvm_mmu_memory_cache *memcache)
> +{
> +	phys_addr_t dst_phys = page_to_phys(dst_page);
> +	phys_addr_t rd = virt_to_phys(realm->rd);
> +	unsigned long phys = dst_phys;
> +	unsigned long ipa = base_ipa;
> +	unsigned long size;
> +	int map_level;
> +	int ret = 0;
> +
> +	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
> +		return -EINVAL;
> +
> +	switch (map_size) {
> +	case PAGE_SIZE:
> +		map_level = 3;
> +		break;
> +	case RME_L2_BLOCK_SIZE:
> +		map_level = 2;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (map_level < RME_RTT_MAX_LEVEL) {
> +		/*
> +		 * A temporary RTT is needed during the map, precreate it,
> +		 * however if there is an error (e.g. missing parent tables)
> +		 * this will be handled below.
> +		 */
> +		realm_create_rtt_levels(realm, ipa, map_level,
> +					RME_RTT_MAX_LEVEL, memcache);
> +	}
> +
> +	for (size = 0; size < map_size; size += PAGE_SIZE) {
> +		if (rmi_granule_delegate(phys)) {
> +			struct rtt_entry rtt;
> +
> +			/*
> +			 * It's possible we raced with another VCPU on the same
> +			 * fault. If the entry exists and matches then exit
> +			 * early and assume the other VCPU will handle the
> +			 * mapping.
> +			 */
> +			if (rmi_rtt_read_entry(rd, ipa, RME_RTT_MAX_LEVEL, &rtt))
> +				goto err;
> +
> +			/*
> +			 * FIXME: For a block mapping this could race at level
> +			 * 2 or 3... currently we don't support block mappings
> +			 */
> +			if (WARN_ON((rtt.walk_level != RME_RTT_MAX_LEVEL ||
> +				     rtt.state != RMI_ASSIGNED ||
> +				     rtt_get_phys(realm, &rtt) != phys))) {

Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

On 04/09/2024 15:48, Jean-Philippe Brucker wrote:
> On Wed, Aug 21, 2024 at 04:38:22PM +0100, Steven Price wrote:
>> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
>> index 2c4e28b457be..337b3dd1e00c 100644
>> --- a/arch/arm64/kvm/rme.c
>> +++ b/arch/arm64/kvm/rme.c
>> @@ -627,6 +627,181 @@ static int fold_rtt(struct realm *realm, unsigned long addr, int level)
>>  	return 0;
>>  }
>>  
>> +static phys_addr_t rtt_get_phys(struct realm *realm, struct rtt_entry *rtt)
>> +{
>> +	bool lpa2 = realm->params->flags & RMI_REALM_PARAM_FLAG_LPA2;
> 
> At this point realm->params is NULL, cleared by kvm_create_realm()

Ah, indeed so. Also LPA2 isn't yet supported (we have no way of setting
that flag).

Since this code is only called for block mappings (also not yet
supported) that explains why I've never seen the issue.

Thanks,
Steve

> Thanks,
> Jean
> 
>> +
>> +	if (lpa2)
>> +		return rtt->desc & GENMASK(49, 12);
>> +	return rtt->desc & GENMASK(47, 12);
>> +}
>> +
>> +int realm_map_protected(struct realm *realm,
>> +			unsigned long base_ipa,
>> +			struct page *dst_page,
>> +			unsigned long map_size,
>> +			struct kvm_mmu_memory_cache *memcache)
>> +{
>> +	phys_addr_t dst_phys = page_to_phys(dst_page);
>> +	phys_addr_t rd = virt_to_phys(realm->rd);
>> +	unsigned long phys = dst_phys;
>> +	unsigned long ipa = base_ipa;
>> +	unsigned long size;
>> +	int map_level;
>> +	int ret = 0;
>> +
>> +	if (WARN_ON(!IS_ALIGNED(ipa, map_size)))
>> +		return -EINVAL;
>> +
>> +	switch (map_size) {
>> +	case PAGE_SIZE:
>> +		map_level = 3;
>> +		break;
>> +	case RME_L2_BLOCK_SIZE:
>> +		map_level = 2;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (map_level < RME_RTT_MAX_LEVEL) {
>> +		/*
>> +		 * A temporary RTT is needed during the map, precreate it,
>> +		 * however if there is an error (e.g. missing parent tables)
>> +		 * this will be handled below.
>> +		 */
>> +		realm_create_rtt_levels(realm, ipa, map_level,
>> +					RME_RTT_MAX_LEVEL, memcache);
>> +	}
>> +
>> +	for (size = 0; size < map_size; size += PAGE_SIZE) {
>> +		if (rmi_granule_delegate(phys)) {
>> +			struct rtt_entry rtt;
>> +
>> +			/*
>> +			 * It's possible we raced with another VCPU on the same
>> +			 * fault. If the entry exists and matches then exit
>> +			 * early and assume the other VCPU will handle the
>> +			 * mapping.
>> +			 */
>> +			if (rmi_rtt_read_entry(rd, ipa, RME_RTT_MAX_LEVEL, &rtt))
>> +				goto err;
>> +
>> +			/*
>> +			 * FIXME: For a block mapping this could race at level
>> +			 * 2 or 3... currently we don't support block mappings
>> +			 */
>> +			if (WARN_ON((rtt.walk_level != RME_RTT_MAX_LEVEL ||
>> +				     rtt.state != RMI_ASSIGNED ||
>> +				     rtt_get_phys(realm, &rtt) != phys))) {
> 

[PATCH v4 22/43] KVM: arm64: Handle realm VCPU load

[Steven Price]

When loading a realm VCPU much of the work is handled by the RMM so only
some of the actions are required. Rearrange kvm_arch_vcpu_load()
slightly so we can bail out early for a realm guest.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e8dabb996705..3d21659ae5ad 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -662,10 +662,6 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	kvm_vgic_load(vcpu);
 	kvm_timer_vcpu_load(vcpu);
-	if (has_vhe())
-		kvm_vcpu_load_vhe(vcpu);
-	kvm_arch_vcpu_load_fp(vcpu);
-	kvm_vcpu_pmu_restore_guest(vcpu);
 	if (kvm_arm_is_pvtime_enabled(&vcpu->arch))
 		kvm_make_request(KVM_REQ_RECORD_STEAL, vcpu);
 
@@ -681,6 +677,15 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	vcpu_set_pauth_traps(vcpu);
 
+	/* No additional state needs to be loaded on Realmed VMs */
+	if (vcpu_is_rec(vcpu))
+		return;
+
+	if (has_vhe())
+		kvm_vcpu_load_vhe(vcpu);
+	kvm_arch_vcpu_load_fp(vcpu);
+	kvm_vcpu_pmu_restore_guest(vcpu);
+
 	kvm_arch_vcpu_load_debug_state_flags(vcpu);
 
 	if (!cpumask_test_cpu(cpu, vcpu->kvm->arch.supported_cpus))
-- 
2.34.1

[PATCH v4 23/43] KVM: arm64: Validate register access for a Realm VM

[Steven Price]

The RMM only allows setting the lower GPRS (x0-x7) and PC for a realm
guest. Check this in kvm_arm_set_reg() so that the VMM can receive a
suitable error return if other registers are accessed.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/guest.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 11098eb7eb44..8066d3f05403 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -783,12 +783,38 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	return kvm_arm_sys_reg_get_reg(vcpu, reg);
 }
 
+/*
+ * The RMI ABI only enables setting the lower GPRs (x0-x7) and PC.
+ * All other registers are reset to architectural or otherwise defined reset
+ * values by the RMM, except for a few configuration fields that correspond to
+ * Realm parameters.
+ */
+static bool validate_realm_set_reg(struct kvm_vcpu *vcpu,
+				   const struct kvm_one_reg *reg)
+{
+	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE) {
+		u64 off = core_reg_offset_from_id(reg->id);
+
+		switch (off) {
+		case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
+		     KVM_REG_ARM_CORE_REG(regs.regs[7]):
+		case KVM_REG_ARM_CORE_REG(regs.pc):
+			return true;
+		}
+	}
+
+	return false;
+}
+
 int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 {
 	/* We currently use nothing arch-specific in upper 32 bits */
 	if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM64 >> 32)
 		return -EINVAL;
 
+	if (kvm_is_realm(vcpu->kvm) && !validate_realm_set_reg(vcpu, reg))
+		return -EINVAL;
+
 	switch (reg->id & KVM_REG_ARM_COPROC_MASK) {
 	case KVM_REG_ARM_CORE:	return set_core_reg(vcpu, reg);
 	case KVM_REG_ARM_FW:
-- 
2.34.1

[PATCH v4 24/43] KVM: arm64: Handle Realm PSCI requests

[Steven Price]

The RMM needs to be informed of the target REC when a PSCI call is made
with an MPIDR argument. Expose an ioctl to the userspace in case the PSCI
is handled by it.

Co-developed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h |  3 +++
 arch/arm64/kvm/arm.c             | 25 +++++++++++++++++++++++++
 arch/arm64/kvm/psci.c            | 29 +++++++++++++++++++++++++++++
 arch/arm64/kvm/rme.c             | 15 +++++++++++++++
 4 files changed, 72 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index c50854f44674..5492e60aa8de 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -117,6 +117,9 @@ int realm_set_ipa_state(struct kvm_vcpu *vcpu,
 			unsigned long addr, unsigned long end,
 			unsigned long ripas,
 			unsigned long *top_ipa);
+int realm_psci_complete(struct kvm_vcpu *calling,
+			struct kvm_vcpu *target,
+			unsigned long status);
 
 #define RME_RTT_BLOCK_LEVEL	2
 #define RME_RTT_MAX_LEVEL	3
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3d21659ae5ad..c57ed4f41bbc 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1756,6 +1756,22 @@ static int kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 	return __kvm_arm_vcpu_set_events(vcpu, events);
 }
 
+static int kvm_arm_vcpu_rmm_psci_complete(struct kvm_vcpu *vcpu,
+					  struct kvm_arm_rmm_psci_complete *arg)
+{
+	struct kvm_vcpu *target = kvm_mpidr_to_vcpu(vcpu->kvm, arg->target_mpidr);
+
+	if (!target)
+		return -EINVAL;
+
+	/*
+	 * RMM v1.0 only supports PSCI_RET_SUCCESS or PSCI_RET_DENIED
+	 * for the status. But, let us leave it to the RMM to filter
+	 * for making this future proof.
+	 */
+	return realm_psci_complete(vcpu, target, arg->psci_status);
+}
+
 long kvm_arch_vcpu_ioctl(struct file *filp,
 			 unsigned int ioctl, unsigned long arg)
 {
@@ -1878,6 +1894,15 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 
 		return kvm_arm_vcpu_finalize(vcpu, what);
 	}
+	case KVM_ARM_VCPU_RMM_PSCI_COMPLETE: {
+		struct kvm_arm_rmm_psci_complete req;
+
+		if (!kvm_is_realm(vcpu->kvm))
+			return -EINVAL;
+		if (copy_from_user(&req, argp, sizeof(req)))
+			return -EFAULT;
+		return kvm_arm_vcpu_rmm_psci_complete(vcpu, &req);
+	}
 	default:
 		r = -EINVAL;
 	}
diff --git a/arch/arm64/kvm/psci.c b/arch/arm64/kvm/psci.c
index 1f69b667332b..f9abab5d50d7 100644
--- a/arch/arm64/kvm/psci.c
+++ b/arch/arm64/kvm/psci.c
@@ -103,6 +103,12 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 
 	reset_state->reset = true;
 	kvm_make_request(KVM_REQ_VCPU_RESET, vcpu);
+	/*
+	 * Make sure we issue PSCI_COMPLETE before the VCPU can be
+	 * scheduled.
+	 */
+	if (vcpu_is_rec(vcpu))
+		realm_psci_complete(source_vcpu, vcpu, PSCI_RET_SUCCESS);
 
 	/*
 	 * Make sure the reset request is observed if the RUNNABLE mp_state is
@@ -115,6 +121,10 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
 
 out_unlock:
 	spin_unlock(&vcpu->arch.mp_state_lock);
+	if (vcpu_is_rec(vcpu) && ret != PSCI_RET_SUCCESS)
+		realm_psci_complete(source_vcpu, vcpu,
+				    ret == PSCI_RET_ALREADY_ON ?
+				    PSCI_RET_SUCCESS : PSCI_RET_DENIED);
 	return ret;
 }
 
@@ -142,6 +152,25 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
 	/* Ignore other bits of target affinity */
 	target_affinity &= target_affinity_mask;
 
+	if (vcpu_is_rec(vcpu)) {
+		struct kvm_vcpu *target_vcpu;
+
+		/* RMM supports only zero affinity level */
+		if (lowest_affinity_level != 0)
+			return PSCI_RET_INVALID_PARAMS;
+
+		target_vcpu = kvm_mpidr_to_vcpu(kvm, target_affinity);
+		if (!target_vcpu)
+			return PSCI_RET_INVALID_PARAMS;
+
+		/*
+		 * Provide the references of running and target RECs to the RMM
+		 * so that the RMM can complete the PSCI request.
+		 */
+		realm_psci_complete(vcpu, target_vcpu, PSCI_RET_SUCCESS);
+		return PSCI_RET_SUCCESS;
+	}
+
 	/*
 	 * If one or more VCPU matching target affinity are running
 	 * then ON else OFF
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 337b3dd1e00c..45d49d12a34c 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -95,6 +95,21 @@ static void free_delegated_page(struct realm *realm, phys_addr_t phys)
 	free_page((unsigned long)phys_to_virt(phys));
 }
 
+int realm_psci_complete(struct kvm_vcpu *calling, struct kvm_vcpu *target,
+			unsigned long status)
+{
+	int ret;
+
+	ret = rmi_psci_complete(virt_to_phys(calling->arch.rec.rec_page),
+				virt_to_phys(target->arch.rec.rec_page),
+				status);
+
+	if (ret)
+		return -EINVAL;
+
+	return 0;
+}
+
 static int realm_rtt_create(struct realm *realm,
 			    unsigned long addr,
 			    int level,
-- 
2.34.1

[PATCH v4 25/43] KVM: arm64: WARN on injected undef exceptions

[Steven Price]

The RMM doesn't allow injection of a undefined exception into a realm
guest. Add a WARN to catch if this ever happens.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/inject_fault.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c
index a640e839848e..44ce1c9bdc2e 100644
--- a/arch/arm64/kvm/inject_fault.c
+++ b/arch/arm64/kvm/inject_fault.c
@@ -224,6 +224,8 @@ void kvm_inject_size_fault(struct kvm_vcpu *vcpu)
  */
 void kvm_inject_undefined(struct kvm_vcpu *vcpu)
 {
+	if (vcpu_is_rec(vcpu))
+		WARN(1, "Cannot inject undefined exception into REC. Continuing with unknown behaviour");
 	if (vcpu_el1_is_32bit(vcpu))
 		inject_undef32(vcpu);
 	else
-- 
2.34.1

[PATCH v4 26/43] arm64: Don't expose stolen time for realm guests

[Steven Price]

It doesn't make much sense as a realm guest wouldn't want to trust the
host. It will also need some extra work to ensure that KVM will only
attempt to write into a shared memory region. So for now just disable
it.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index c57ed4f41bbc..2d7cbd4a2483 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -429,7 +429,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = system_supports_mte();
 		break;
 	case KVM_CAP_STEAL_TIME:
-		r = kvm_arm_pvtime_supported();
+		if (kvm_is_realm(kvm))
+			r = 0;
+		else
+			r = kvm_arm_pvtime_supported();
 		break;
 	case KVM_CAP_ARM_EL1_32BIT:
 		r = cpus_have_final_cap(ARM64_HAS_32BIT_EL1);
-- 
2.34.1

[PATCH v4 27/43] arm64: rme: allow userspace to inject aborts

[Steven Price]

From: Joey Gouly <joey.gouly@arm.com>

Extend KVM_SET_VCPU_EVENTS to support realms, where KVM cannot set the
system registers, and the RMM must perform it on next REC entry.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 Documentation/virt/kvm/api.rst |  2 ++
 arch/arm64/kvm/guest.c         | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 849ddd2735ca..08652004aa07 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -1278,6 +1278,8 @@ User space may need to inject several types of events to the guest.
 Set the pending SError exception state for this VCPU. It is not possible to
 'cancel' an Serror that has been made pending.
 
+User space cannot inject SErrors into Realms.
+
 If the guest performed an access to I/O memory which could not be handled by
 userspace, for example because of missing instruction syndrome decode
 information or because there is no device mapped at the accessed IPA, then
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 8066d3f05403..88c07c880e88 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -866,6 +866,30 @@ int __kvm_arm_vcpu_set_events(struct kvm_vcpu *vcpu,
 	bool has_esr = events->exception.serror_has_esr;
 	bool ext_dabt_pending = events->exception.ext_dabt_pending;
 
+	if (vcpu_is_rec(vcpu)) {
+		/* Cannot inject SError into a Realm. */
+		if (serror_pending)
+			return -EINVAL;
+
+		/*
+		 * If a data abort is pending, set the flag and let the RMM
+		 * inject an SEA when the REC is scheduled to be run.
+		 */
+		if (ext_dabt_pending) {
+			/*
+			 * Can only inject SEA into a Realm if the previous exit
+			 * was due to a data abort of an Unprotected IPA.
+			 */
+			if (!(vcpu->arch.rec.run->enter.flags & RMI_EMULATED_MMIO))
+				return -EINVAL;
+
+			vcpu->arch.rec.run->enter.flags &= ~RMI_EMULATED_MMIO;
+			vcpu->arch.rec.run->enter.flags |= RMI_INJECT_SEA;
+		}
+
+		return 0;
+	}
+
 	if (serror_pending && has_esr) {
 		if (!cpus_have_final_cap(ARM64_HAS_RAS_EXTN))
 			return -EINVAL;
-- 
2.34.1

[PATCH v4 28/43] arm64: rme: support RSI_HOST_CALL

[Steven Price]

From: Joey Gouly <joey.gouly@arm.com>

Forward RSI_HOST_CALLS to KVM's HVC handler.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/rme-exit.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/arch/arm64/kvm/rme-exit.c b/arch/arm64/kvm/rme-exit.c
index 03ed147f7926..0940575b0a14 100644
--- a/arch/arm64/kvm/rme-exit.c
+++ b/arch/arm64/kvm/rme-exit.c
@@ -117,6 +117,29 @@ static int rec_exit_ripas_change(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+static int rec_exit_host_call(struct kvm_vcpu *vcpu)
+{
+	int ret, i;
+	struct realm_rec *rec = &vcpu->arch.rec;
+
+	vcpu->stat.hvc_exit_stat++;
+
+	for (i = 0; i < REC_RUN_GPRS; i++)
+		vcpu_set_reg(vcpu, i, rec->run->exit.gprs[i]);
+
+	ret = kvm_smccc_call_handler(vcpu);
+
+	if (ret < 0) {
+		vcpu_set_reg(vcpu, 0, ~0UL);
+		ret = 1;
+	}
+
+	for (i = 0; i < REC_RUN_GPRS; i++)
+		rec->run->enter.gprs[i] = vcpu_get_reg(vcpu, i);
+
+	return ret;
+}
+
 static void update_arch_timer_irq_lines(struct kvm_vcpu *vcpu)
 {
 	struct realm_rec *rec = &vcpu->arch.rec;
@@ -178,6 +201,8 @@ int handle_rme_exit(struct kvm_vcpu *vcpu, int rec_run_ret)
 		return rec_exit_psci(vcpu);
 	case RMI_EXIT_RIPAS_CHANGE:
 		return rec_exit_ripas_change(vcpu);
+	case RMI_EXIT_HOST_CALL:
+		return rec_exit_host_call(vcpu);
 	}
 
 	kvm_pr_unimpl("Unsupported exit reason: %u\n",
-- 
2.34.1

[PATCH v4 29/43] arm64: rme: Allow checking SVE on VM instance

[Steven Price]

From: Suzuki K Poulose <suzuki.poulose@arm.com>

Given we have different types of VMs supported, check the
support for SVE for the given instance of the VM to accurately
report the status.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h | 2 ++
 arch/arm64/kvm/arm.c             | 5 ++++-
 arch/arm64/kvm/rme.c             | 5 +++++
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 5492e60aa8de..80c7db964079 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -89,6 +89,8 @@ struct realm_rec {
 void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
 
+bool kvm_rme_supports_sve(void);
+
 int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap);
 int kvm_init_realm_vm(struct kvm *kvm);
 void kvm_destroy_realm(struct kvm *kvm);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 2d7cbd4a2483..bb9b9788aa94 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -453,7 +453,10 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 		r = get_kvm_ipa_limit();
 		break;
 	case KVM_CAP_ARM_SVE:
-		r = system_supports_sve();
+		if (kvm_is_realm(kvm))
+			r = kvm_rme_supports_sve();
+		else
+			r = system_supports_sve();
 		break;
 	case KVM_CAP_ARM_PTRAUTH_ADDRESS:
 	case KVM_CAP_ARM_PTRAUTH_GENERIC:
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 45d49d12a34c..999bd4bf2d73 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -20,6 +20,11 @@ static bool rme_supports(unsigned long feature)
 	return !!u64_get_bits(rmm_feat_reg0, feature);
 }
 
+bool kvm_rme_supports_sve(void)
+{
+	return rme_supports(RMI_FEATURE_REGISTER_0_SVE_EN);
+}
+
 static int rmi_check_version(void)
 {
 	struct arm_smccc_res res;
-- 
2.34.1

[PATCH v4 30/43] arm64: RME: Always use 4k pages for realms

[Steven Price]

Always split up huge pages to avoid problems managing huge pages. There
are two issues currently:

1. The uABI for the VMM allows populating memory on 4k boundaries even
   if the underlying allocator (e.g. hugetlbfs) is using a larger page
   size. Using a memfd for private allocations will push this issue onto
   the VMM as it will need to respect the granularity of the allocator.

2. The guest is able to request arbitrary ranges to be remapped as
   shared. Again with a memfd approach it will be up to the VMM to deal
   with the complexity and either overmap (need the huge mapping and add
   an additional 'overlapping' shared mapping) or reject the request as
   invalid due to the use of a huge page allocator.

For now just break everything down to 4k pages in the RMM controlled
stage 2.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index eb8b8d013f3e..dfc3dd628e43 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1580,6 +1580,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	if (logging_active) {
 		force_pte = true;
 		vma_shift = PAGE_SHIFT;
+	} else if (kvm_is_realm(kvm)) {
+		// Force PTE level mappings for realms
+		force_pte = true;
+		vma_shift = PAGE_SHIFT;
 	} else {
 		vma_shift = get_vma_page_shift(vma, hva);
 	}
-- 
2.34.1

[PATCH v4 31/43] arm64: rme: Prevent Device mappings for Realms

[Steven Price]

Physical device assignment is not yet supported by the RMM, so it
doesn't make much sense to allow device mappings within the realm.
Prevent them when the guest is a realm.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/mmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index dfc3dd628e43..2110dd4c18db 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1142,6 +1142,10 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 	if (is_protected_kvm_enabled())
 		return -EPERM;
 
+	/* We don't support mapping special pages into a Realm */
+	if (kvm_is_realm(kvm))
+		return -EINVAL;
+
 	size += offset_in_page(guest_ipa);
 	guest_ipa &= PAGE_MASK;
 
-- 
2.34.1

[PATCH v4 32/43] arm_pmu: Provide a mechanism for disabling the physical IRQ

[Steven Price]

Arm CCA assigns the physical PMU device to the guest running in realm
world, however the IRQs are routed via the host. To enter a realm guest
while a PMU IRQ is pending it is necessary to block the physical IRQ to
prevent an immediate exit. Provide a mechanism in the PMU driver for KVM
to control the physical IRQ.

Signed-off-by: Steven Price <steven.price@arm.com>
---
v3: Add a dummy function for the !CONFIG_ARM_PMU case.
---
 drivers/perf/arm_pmu.c       | 15 +++++++++++++++
 include/linux/perf/arm_pmu.h |  5 +++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 8458fe2cebb4..1e024acc98bb 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -735,6 +735,21 @@ static int arm_perf_teardown_cpu(unsigned int cpu, struct hlist_node *node)
 	return 0;
 }
 
+void arm_pmu_set_phys_irq(bool enable)
+{
+	int cpu = get_cpu();
+	struct arm_pmu *pmu = per_cpu(cpu_armpmu, cpu);
+	int irq;
+
+	irq = armpmu_get_cpu_irq(pmu, cpu);
+	if (irq && !enable)
+		per_cpu(cpu_irq_ops, cpu)->disable_pmuirq(irq);
+	else if (irq && enable)
+		per_cpu(cpu_irq_ops, cpu)->enable_pmuirq(irq);
+
+	put_cpu();
+}
+
 #ifdef CONFIG_CPU_PM
 static void cpu_pm_pmu_setup(struct arm_pmu *armpmu, unsigned long cmd)
 {
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index b3b34f6670cf..f9fa628ae2ae 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -168,6 +168,7 @@ void kvm_host_pmu_init(struct arm_pmu *pmu);
 #endif
 
 bool arm_pmu_irq_is_nmi(void);
+void arm_pmu_set_phys_irq(bool enable);
 
 /* Internal functions only for core arm_pmu code */
 struct arm_pmu *armpmu_alloc(void);
@@ -178,6 +179,10 @@ void armpmu_free_irq(int irq, int cpu);
 
 #define ARMV8_PMU_PDEV_NAME "armv8-pmu"
 
+#else /* CONFIG_ARM_PMU */
+
+static inline void arm_pmu_set_phys_irq(bool enable) {}
+
 #endif /* CONFIG_ARM_PMU */
 
 #define ARMV8_SPE_PDEV_NAME "arm,spe-v1"
-- 
2.34.1

[PATCH v4 33/43] arm64: rme: Enable PMU support with a realm guest

[Steven Price]

Use the PMU registers from the RmiRecExit structure to identify when an
overflow interrupt is due and inject it into the guest. Also hook up the
configuration option for enabling the PMU within the guest.

When entering a realm guest with a PMU interrupt pending, it is
necessary to disable the physical interrupt. Otherwise when the RMM
restores the PMU state the physical interrupt will trigger causing an
immediate exit back to the host. The guest is expected to acknowledge
the interrupt causing a host exit (to update the GIC state) which gives
the opportunity to re-enable the physical interrupt before the next PMU
event.

Number of PMU counters is configured by the VMM by writing to PMCR.N.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Add a macro kvm_pmu_get_irq_level() to avoid compile issues when PMU
   support is disabled.
---
 arch/arm64/kvm/arm.c      | 11 +++++++++++
 arch/arm64/kvm/guest.c    |  7 +++++++
 arch/arm64/kvm/pmu-emul.c |  4 +++-
 arch/arm64/kvm/rme.c      |  8 ++++++++
 arch/arm64/kvm/sys_regs.c |  2 +-
 include/kvm/arm_pmu.h     |  4 ++++
 6 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index bb9b9788aa94..fe815a0d20bf 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -15,6 +15,7 @@
 #include <linux/vmalloc.h>
 #include <linux/fs.h>
 #include <linux/mman.h>
+#include <linux/perf/arm_pmu.h>
 #include <linux/sched.h>
 #include <linux/kvm.h>
 #include <linux/kvm_irqfd.h>
@@ -1227,6 +1228,8 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 	run->exit_reason = KVM_EXIT_UNKNOWN;
 	run->flags = 0;
 	while (ret > 0) {
+		bool pmu_stopped = false;
+
 		/*
 		 * Check conditions before entering the guest
 		 */
@@ -1258,6 +1261,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 
 		kvm_pmu_flush_hwstate(vcpu);
 
+		if (vcpu_is_rec(vcpu) && kvm_pmu_get_irq_level(vcpu)) {
+			pmu_stopped = true;
+			arm_pmu_set_phys_irq(false);
+		}
+
 		local_irq_disable();
 
 		kvm_vgic_flush_hwstate(vcpu);
@@ -1360,6 +1368,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
 
 		preempt_enable();
 
+		if (pmu_stopped)
+			arm_pmu_set_phys_irq(true);
+
 		/*
 		 * The ARMv8 architecture doesn't give the hypervisor
 		 * a mechanism to prevent a guest from dropping to AArch32 EL0
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 88c07c880e88..24d8220c1d67 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -783,6 +783,8 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	return kvm_arm_sys_reg_get_reg(vcpu, reg);
 }
 
+#define KVM_REG_ARM_PMCR_EL0		ARM64_SYS_REG(3, 3, 9, 12, 0)
+
 /*
  * The RMI ABI only enables setting the lower GPRs (x0-x7) and PC.
  * All other registers are reset to architectural or otherwise defined reset
@@ -801,6 +803,11 @@ static bool validate_realm_set_reg(struct kvm_vcpu *vcpu,
 		case KVM_REG_ARM_CORE_REG(regs.pc):
 			return true;
 		}
+	} else {
+		switch (reg->id) {
+		case KVM_REG_ARM_PMCR_EL0:
+			return true;
+		}
 	}
 
 	return false;
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 82a2a003259c..e3dc2363543b 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -340,7 +340,9 @@ static u64 kvm_pmu_overflow_status(struct kvm_vcpu *vcpu)
 {
 	u64 reg = 0;
 
-	if ((kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E)) {
+	if (vcpu_is_rec(vcpu)) {
+		reg = vcpu->arch.rec.run->exit.pmu_ovf_status;
+	} else if ((kvm_vcpu_read_pmcr(vcpu) & ARMV8_PMU_PMCR_E)) {
 		reg = __vcpu_sys_reg(vcpu, PMOVSSET_EL0);
 		reg &= __vcpu_sys_reg(vcpu, PMCNTENSET_EL0);
 		reg &= __vcpu_sys_reg(vcpu, PMINTENSET_EL1);
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 999bd4bf2d73..93757c550394 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -325,6 +325,11 @@ static int realm_create_rd(struct kvm *kvm)
 	params->rtt_base = kvm->arch.mmu.pgd_phys;
 	params->vmid = realm->vmid;
 
+	if (kvm->arch.arm_pmu) {
+		params->pmu_num_ctrs = kvm->arch.pmcr_n;
+		params->flags |= RMI_REALM_PARAM_FLAG_PMU;
+	}
+
 	params_phys = virt_to_phys(params);
 
 	if (rmi_realm_create(rd_phys, params_phys)) {
@@ -1398,6 +1403,9 @@ int kvm_create_rec(struct kvm_vcpu *vcpu)
 	if (!vcpu_has_feature(vcpu, KVM_ARM_VCPU_PSCI_0_2))
 		return -EINVAL;
 
+	if (vcpu->kvm->arch.arm_pmu && !kvm_vcpu_has_pmu(vcpu))
+		return -EINVAL;
+
 	BUILD_BUG_ON(sizeof(*params) > PAGE_SIZE);
 	BUILD_BUG_ON(sizeof(*rec->run) > PAGE_SIZE);
 
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c90324060436..39a1ea231a09 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1286,7 +1286,7 @@ static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	 * implements. Ignore this error to maintain compatibility
 	 * with the existing KVM behavior.
 	 */
-	if (!kvm_vm_has_ran_once(kvm) &&
+	if (!kvm_vm_has_ran_once(kvm) && !kvm_realm_is_created(kvm) &&
 	    new_n <= kvm_arm_pmu_get_max_counters(kvm))
 		kvm->arch.pmcr_n = new_n;
 
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 35d4ca4f6122..e2d31640e2e7 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -76,6 +76,8 @@ void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu);
 void kvm_vcpu_pmu_resync_el0(void);
 
+#define kvm_pmu_get_irq_level(vcpu) ((vcpu)->arch.pmu.irq_level)
+
 #define kvm_vcpu_has_pmu(vcpu)					\
 	(vcpu_has_feature(vcpu, KVM_ARM_VCPU_PMU_V3))
 
@@ -157,6 +159,8 @@ static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 	return 0;
 }
 
+#define kvm_pmu_get_irq_level(vcpu) (false)
+
 #define kvm_vcpu_has_pmu(vcpu)		({ false; })
 static inline void kvm_pmu_update_vcpu_events(struct kvm_vcpu *vcpu) {}
 static inline void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) {}
-- 
2.34.1

[PATCH v4 34/43] kvm: rme: Hide KVM_CAP_READONLY_MEM for realm guests

[Steven Price]

For protected memory read only isn't supported. While it may be possible
to support read only for unprotected memory, this isn't supported at the
present time.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index fe815a0d20bf..bd79a928d036 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -374,7 +374,6 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_ONE_REG:
 	case KVM_CAP_ARM_PSCI:
 	case KVM_CAP_ARM_PSCI_0_2:
-	case KVM_CAP_READONLY_MEM:
 	case KVM_CAP_MP_STATE:
 	case KVM_CAP_IMMEDIATE_EXIT:
 	case KVM_CAP_VCPU_EVENTS:
@@ -388,6 +387,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_COUNTER_OFFSET:
 		r = 1;
 		break;
+	case KVM_CAP_READONLY_MEM:
 	case KVM_CAP_SET_GUEST_DEBUG:
 		r = !kvm_is_realm(kvm);
 		break;
-- 
2.34.1

[PATCH v4 35/43] arm64: RME: Propagate number of breakpoints and watchpoints to userspace

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

The RMM describes the maximum number of BPs/WPs available to the guest
in the Feature Register 0. Propagate those numbers into ID_AA64DFR0_EL1,
which is visible to userspace. A VMM needs this information in order to
set up realm parameters.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h |  1 +
 arch/arm64/kvm/rme.c             | 22 ++++++++++++++++++++++
 arch/arm64/kvm/sys_regs.c        |  2 +-
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 80c7db964079..8aa02134c461 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -88,6 +88,7 @@ struct realm_rec {
 
 void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
+u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);
 
 bool kvm_rme_supports_sve(void);
 
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 93757c550394..5d9f732f4df2 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -286,6 +286,28 @@ u32 kvm_realm_ipa_limit(void)
 	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
 }
 
+u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
+{
+	u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
+	u32 wps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_WPS);
+	u32 ctx_cmps;
+
+	if (!kvm_is_realm(vcpu->kvm))
+		return val;
+
+	/* Ensure CTX_CMPs is still valid */
+	ctx_cmps = FIELD_GET(ID_AA64DFR0_EL1_CTX_CMPs, val);
+	ctx_cmps = min(bps, ctx_cmps);
+
+	val &= ~(ID_AA64DFR0_EL1_BRPs_MASK | ID_AA64DFR0_EL1_WRPs_MASK |
+		 ID_AA64DFR0_EL1_CTX_CMPs);
+	val |= FIELD_PREP(ID_AA64DFR0_EL1_BRPs_MASK, bps) |
+	       FIELD_PREP(ID_AA64DFR0_EL1_WRPs_MASK, wps) |
+	       FIELD_PREP(ID_AA64DFR0_EL1_CTX_CMPs, ctx_cmps);
+
+	return val;
+}
+
 static int realm_create_rd(struct kvm *kvm)
 {
 	struct realm *realm = &kvm->arch.realm;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 39a1ea231a09..c7a5b1a8a224 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1732,7 +1732,7 @@ static u64 read_sanitised_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
 	/* Hide SPE from guests */
 	val &= ~ID_AA64DFR0_EL1_PMSVer_MASK;
 
-	return val;
+	return kvm_realm_reset_id_aa64dfr0_el1(vcpu, val);
 }
 
 static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
-- 
2.34.1

[PATCH v4 36/43] arm64: RME: Set breakpoint parameters through SET_ONE_REG

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Allow userspace to configure the number of breakpoints and watchpoints
of a Realm VM through KVM_SET_ONE_REG ID_AA64DFR0_EL1.

The KVM sys_reg handler checks the user value against the maximum value
given by RMM (arm64_check_features() gets it from the
read_sanitised_id_aa64dfr0_el1() reset handler).

Userspace discovers that it can write these fields by issuing a
KVM_ARM_GET_REG_WRITABLE_MASKS ioctl.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/guest.c    |  2 ++
 arch/arm64/kvm/rme.c      |  3 +++
 arch/arm64/kvm/sys_regs.c | 21 ++++++++++++++-------
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 24d8220c1d67..b0cabba974b8 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -784,6 +784,7 @@ int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 }
 
 #define KVM_REG_ARM_PMCR_EL0		ARM64_SYS_REG(3, 3, 9, 12, 0)
+#define KVM_REG_ARM_ID_AA64DFR0_EL1	ARM64_SYS_REG(3, 0, 0, 5, 0)
 
 /*
  * The RMI ABI only enables setting the lower GPRs (x0-x7) and PC.
@@ -806,6 +807,7 @@ static bool validate_realm_set_reg(struct kvm_vcpu *vcpu,
 	} else {
 		switch (reg->id) {
 		case KVM_REG_ARM_PMCR_EL0:
+		case KVM_REG_ARM_ID_AA64DFR0_EL1:
 			return true;
 		}
 	}
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 5d9f732f4df2..42f52b21bdae 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -315,6 +315,7 @@ static int realm_create_rd(struct kvm *kvm)
 	void *rd = NULL;
 	phys_addr_t rd_phys, params_phys;
 	struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
+	u64 dfr0 = kvm_read_vm_id_reg(kvm, SYS_ID_AA64DFR0_EL1);
 	int i, r;
 
 	if (WARN_ON(realm->rd) || WARN_ON(!realm->params))
@@ -346,6 +347,8 @@ static int realm_create_rd(struct kvm *kvm)
 	params->rtt_num_start = pgt->pgd_pages;
 	params->rtt_base = kvm->arch.mmu.pgd_phys;
 	params->vmid = realm->vmid;
+	params->num_bps = SYS_FIELD_GET(ID_AA64DFR0_EL1, BRPs, dfr0);
+	params->num_wps = SYS_FIELD_GET(ID_AA64DFR0_EL1, WRPs, dfr0);
 
 	if (kvm->arch.arm_pmu) {
 		params->pmu_num_ctrs = kvm->arch.pmcr_n;
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index c7a5b1a8a224..f92b78039dce 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1741,6 +1741,9 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
 {
 	u8 debugver = SYS_FIELD_GET(ID_AA64DFR0_EL1, DebugVer, val);
 	u8 pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, val);
+	u8 bps = SYS_FIELD_GET(ID_AA64DFR0_EL1, BRPs, val);
+	u8 wps = SYS_FIELD_GET(ID_AA64DFR0_EL1, WRPs, val);
+	u8 ctx_cmps = SYS_FIELD_GET(ID_AA64DFR0_EL1, CTX_CMPs, val);
 
 	/*
 	 * Prior to commit 3d0dba5764b9 ("KVM: arm64: PMU: Move the
@@ -1760,10 +1763,11 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
 		val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
 
 	/*
-	 * ID_AA64DFR0_EL1.DebugVer is one of those awkward fields with a
-	 * nonzero minimum safe value.
+	 * ID_AA64DFR0_EL1.DebugVer, BRPs and WRPs all have to be greater than
+	 * zero. CTX_CMPs is never greater than BRPs.
 	 */
-	if (debugver < ID_AA64DFR0_EL1_DebugVer_IMP)
+	if (debugver < ID_AA64DFR0_EL1_DebugVer_IMP || !bps || !wps ||
+	    ctx_cmps > bps)
 		return -EINVAL;
 
 	return set_id_reg(vcpu, rd, val);
@@ -1846,10 +1850,11 @@ static int set_id_reg(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd,
 	mutex_lock(&vcpu->kvm->arch.config_lock);
 
 	/*
-	 * Once the VM has started the ID registers are immutable. Reject any
-	 * write that does not match the final register value.
+	 * Once the VM has started or the Realm descriptor is created, the ID
+	 * registers are immutable. Reject any write that does not match the
+	 * final register value.
 	 */
-	if (kvm_vm_has_ran_once(vcpu->kvm)) {
+	if (kvm_vm_has_ran_once(vcpu->kvm) || kvm_realm_is_created(vcpu->kvm)) {
 		if (val != read_id_reg(vcpu, rd))
 			ret = -EBUSY;
 		else
@@ -2377,7 +2382,9 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	  .set_user = set_id_aa64dfr0_el1,
 	  .reset = read_sanitised_id_aa64dfr0_el1,
 	  .val = ID_AA64DFR0_EL1_PMUVer_MASK |
-		 ID_AA64DFR0_EL1_DebugVer_MASK, },
+		 ID_AA64DFR0_EL1_DebugVer_MASK |
+		 ID_AA64DFR0_EL1_BRPs_MASK |
+		 ID_AA64DFR0_EL1_WRPs_MASK, },
 	ID_SANITISED(ID_AA64DFR1_EL1),
 	ID_UNALLOCATED(5,2),
 	ID_UNALLOCATED(5,3),
-- 
2.34.1

[PATCH v4 37/43] arm64: RME: Initialize PMCR.N with number counter supported by RMM

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Provide an accurate number of available PMU counters to userspace when
setting up a Realm.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_rme.h | 1 +
 arch/arm64/kvm/pmu-emul.c        | 3 +++
 arch/arm64/kvm/rme.c             | 5 +++++
 3 files changed, 9 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index 8aa02134c461..c30d7899f58b 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -88,6 +88,7 @@ struct realm_rec {
 
 void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
+u8 kvm_realm_max_pmu_counters(void);
 u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);
 
 bool kvm_rme_supports_sve(void);
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index e3dc2363543b..af4e03251503 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -911,6 +911,9 @@ u8 kvm_arm_pmu_get_max_counters(struct kvm *kvm)
 {
 	struct arm_pmu *arm_pmu = kvm->arch.arm_pmu;
 
+	if (kvm_is_realm(kvm))
+		return kvm_realm_max_pmu_counters();
+
 	/*
 	 * The arm_pmu->num_events considers the cycle counter as well.
 	 * Ignore that and return only the general-purpose counters.
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 42f52b21bdae..a8cb274c9d03 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -286,6 +286,11 @@ u32 kvm_realm_ipa_limit(void)
 	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_S2SZ);
 }
 
+u8 kvm_realm_max_pmu_counters(void)
+{
+	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS);
+}
+
 u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
 {
 	u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
-- 
2.34.1

[PATCH v4 38/43] arm64: RME: Propagate max SVE vector length from RMM

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

RMM provides the maximum vector length it supports for a guest in its
feature register. Make it visible to the rest of KVM and to userspace
via KVM_REG_ARM64_SVE_VLS.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/include/asm/kvm_host.h |  3 ++-
 arch/arm64/include/asm/kvm_rme.h  |  1 +
 arch/arm64/kvm/guest.c            |  2 +-
 arch/arm64/kvm/reset.c            | 12 ++++++++++--
 arch/arm64/kvm/rme.c              |  6 ++++++
 5 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27e4ae382b38..178e02dc4927 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -76,9 +76,10 @@ static inline enum kvm_mode kvm_get_mode(void) { return KVM_MODE_NONE; };
 
 DECLARE_STATIC_KEY_FALSE(userspace_irqchip_in_use);
 
-extern unsigned int __ro_after_init kvm_sve_max_vl;
 extern unsigned int __ro_after_init kvm_host_sve_max_vl;
+
 int __init kvm_arm_init_sve(void);
+unsigned int kvm_sve_get_max_vl(struct kvm *kvm);
 
 u32 __attribute_const__ kvm_target_cpu(void);
 void kvm_reset_vcpu(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/include/asm/kvm_rme.h b/arch/arm64/include/asm/kvm_rme.h
index c30d7899f58b..a72e06cf4ea6 100644
--- a/arch/arm64/include/asm/kvm_rme.h
+++ b/arch/arm64/include/asm/kvm_rme.h
@@ -89,6 +89,7 @@ struct realm_rec {
 void kvm_init_rme(void);
 u32 kvm_realm_ipa_limit(void);
 u8 kvm_realm_max_pmu_counters(void);
+unsigned int kvm_realm_sve_max_vl(void);
 u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val);
 
 bool kvm_rme_supports_sve(void);
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index b0cabba974b8..ba4dde3032d3 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -356,7 +356,7 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 		if (vq_present(vqs, vq))
 			max_vq = vq;
 
-	if (max_vq > sve_vq_from_vl(kvm_sve_max_vl))
+	if (max_vq > sve_vq_from_vl(kvm_sve_get_max_vl(vcpu->kvm)))
 		return -EINVAL;
 
 	/*
diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
index 845b1ece47d4..0f6e8e7b3c53 100644
--- a/arch/arm64/kvm/reset.c
+++ b/arch/arm64/kvm/reset.c
@@ -46,7 +46,7 @@ unsigned int __ro_after_init kvm_host_sve_max_vl;
 #define VCPU_RESET_PSTATE_SVC	(PSR_AA32_MODE_SVC | PSR_AA32_A_BIT | \
 				 PSR_AA32_I_BIT | PSR_AA32_F_BIT)
 
-unsigned int __ro_after_init kvm_sve_max_vl;
+static unsigned int __ro_after_init kvm_sve_max_vl;
 
 int __init kvm_arm_init_sve(void)
 {
@@ -76,9 +76,17 @@ int __init kvm_arm_init_sve(void)
 	return 0;
 }
 
+unsigned int kvm_sve_get_max_vl(struct kvm *kvm)
+{
+	if (kvm_is_realm(kvm))
+		return kvm_realm_sve_max_vl();
+	else
+		return kvm_sve_max_vl;
+}
+
 static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
 {
-	vcpu->arch.sve_max_vl = kvm_sve_max_vl;
+	vcpu->arch.sve_max_vl = kvm_sve_get_max_vl(vcpu->kvm);
 
 	/*
 	 * Userspace can still customize the vector lengths by writing
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index a8cb274c9d03..64ff00a53c4f 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -291,6 +291,12 @@ u8 kvm_realm_max_pmu_counters(void)
 	return u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_PMU_NUM_CTRS);
 }
 
+unsigned int kvm_realm_sve_max_vl(void)
+{
+	return sve_vl_from_vq(u64_get_bits(rmm_feat_reg0,
+					   RMI_FEATURE_REGISTER_0_SVE_VL) + 1);
+}
+
 u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
 {
 	u32 bps = u64_get_bits(rmm_feat_reg0, RMI_FEATURE_REGISTER_0_NUM_BPS);
-- 
2.34.1

[PATCH v4 39/43] arm64: RME: Configure max SVE vector length for a Realm

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Obtain the max vector length configured by userspace on the vCPUs, and
write it into the Realm parameters. By default the vCPU is configured
with the max vector length reported by RMM, and userspace can reduce it
with a write to KVM_REG_ARM64_SVE_VLS.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/guest.c |  3 ++-
 arch/arm64/kvm/rme.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index ba4dde3032d3..e00b72fba33d 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -342,7 +342,7 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
 	if (!vcpu_has_sve(vcpu))
 		return -ENOENT;
 
-	if (kvm_arm_vcpu_sve_finalized(vcpu))
+	if (kvm_arm_vcpu_sve_finalized(vcpu) || kvm_realm_is_created(vcpu->kvm))
 		return -EPERM; /* too late! */
 
 	if (WARN_ON(vcpu->arch.sve_state))
@@ -808,6 +808,7 @@ static bool validate_realm_set_reg(struct kvm_vcpu *vcpu,
 		switch (reg->id) {
 		case KVM_REG_ARM_PMCR_EL0:
 		case KVM_REG_ARM_ID_AA64DFR0_EL1:
+		case KVM_REG_ARM64_SVE_VLS:
 			return true;
 		}
 	}
diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 64ff00a53c4f..9f415411d3b5 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -319,6 +319,44 @@ u64 kvm_realm_reset_id_aa64dfr0_el1(struct kvm_vcpu *vcpu, u64 val)
 	return val;
 }
 
+static int realm_init_sve_param(struct kvm *kvm, struct realm_params *params)
+{
+	int ret = 0;
+	unsigned long i;
+	struct kvm_vcpu *vcpu;
+	int max_vl, realm_max_vl = -1;
+
+	/*
+	 * Get the preferred SVE configuration, set by userspace with the
+	 * KVM_ARM_VCPU_SVE feature and KVM_REG_ARM64_SVE_VLS pseudo-register.
+	 */
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		mutex_lock(&vcpu->mutex);
+		if (vcpu_has_sve(vcpu)) {
+			if (!kvm_arm_vcpu_sve_finalized(vcpu))
+				ret = -EINVAL;
+			max_vl = vcpu->arch.sve_max_vl;
+		} else {
+			max_vl = 0;
+		}
+		mutex_unlock(&vcpu->mutex);
+		if (ret)
+			return ret;
+
+		/* We need all vCPUs to have the same SVE config */
+		if (realm_max_vl >= 0 && realm_max_vl != max_vl)
+			return -EINVAL;
+
+		realm_max_vl = max_vl;
+	}
+
+	if (realm_max_vl > 0) {
+		params->sve_vl = sve_vq_from_vl(realm_max_vl) - 1;
+		params->flags |= RMI_REALM_PARAM_FLAG_SVE;
+	}
+	return 0;
+}
+
 static int realm_create_rd(struct kvm *kvm)
 {
 	struct realm *realm = &kvm->arch.realm;
@@ -366,6 +404,10 @@ static int realm_create_rd(struct kvm *kvm)
 		params->flags |= RMI_REALM_PARAM_FLAG_PMU;
 	}
 
+	r = realm_init_sve_param(kvm, params);
+	if (r)
+		goto out_undelegate_tables;
+
 	params_phys = virt_to_phys(params);
 
 	if (rmi_realm_create(rd_phys, params_phys)) {
-- 
2.34.1

[PATCH v4 40/43] arm64: RME: Provide register list for unfinalized RME RECs

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

KVM_GET_REG_LIST should not be called before SVE is finalized. The ioctl
handler currently returns -EPERM in this case. But because it uses
kvm_arm_vcpu_is_finalized(), it now also rejects the call for
unfinalized REC even though finalizing the REC can only be done late,
after Realm descriptor creation.

Move the check to copy_sve_reg_indices(). One adverse side effect of
this change is that a KVM_GET_REG_LIST call that only probes for the
array size will now succeed even if SVE is not finalized, but that seems
harmless since the following KVM_GET_REG_LIST with the full array will
fail.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/arm.c   | 4 ----
 arch/arm64/kvm/guest.c | 9 +++------
 2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index bd79a928d036..05d9062470c2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1843,10 +1843,6 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
 		if (unlikely(!kvm_vcpu_initialized(vcpu)))
 			break;
 
-		r = -EPERM;
-		if (!kvm_arm_vcpu_is_finalized(vcpu))
-			break;
-
 		r = -EFAULT;
 		if (copy_from_user(&reg_list, user_list, sizeof(reg_list)))
 			break;
diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index e00b72fba33d..b12b5e4ddd8c 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -653,12 +653,9 @@ static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
 {
 	const unsigned int slices = vcpu_sve_slices(vcpu);
 
-	if (!vcpu_has_sve(vcpu))
+	if (!vcpu_has_sve(vcpu) || !kvm_arm_vcpu_sve_finalized(vcpu))
 		return 0;
 
-	/* Policed by KVM_GET_REG_LIST: */
-	WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu));
-
 	return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */)
 		+ 1; /* KVM_REG_ARM64_SVE_VLS */
 }
@@ -674,8 +671,8 @@ static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu,
 	if (!vcpu_has_sve(vcpu))
 		return 0;
 
-	/* Policed by KVM_GET_REG_LIST: */
-	WARN_ON(!kvm_arm_vcpu_sve_finalized(vcpu));
+	if (!kvm_arm_vcpu_sve_finalized(vcpu))
+		return -EPERM;
 
 	/*
 	 * Enumerate this first, so that userspace can save/restore in
-- 
2.34.1

[PATCH v4 41/43] arm64: RME: Provide accurate register list

[Steven Price]

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

Userspace can set a few registers with KVM_SET_ONE_REG (9 GP registers
at runtime, and 3 system registers during initialization). Update the
register list returned by KVM_GET_REG_LIST.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/guest.c      | 40 ++++++++++++++++++-------
 arch/arm64/kvm/hypercalls.c |  4 +--
 arch/arm64/kvm/sys_regs.c   | 58 ++++++++++++++++++++++++++++---------
 3 files changed, 75 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index b12b5e4ddd8c..1ac0a552550c 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -73,6 +73,17 @@ static u64 core_reg_offset_from_id(u64 id)
 	return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
 }
 
+static bool kvm_realm_validate_core_reg(u64 off)
+{
+	switch (off) {
+	case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
+	     KVM_REG_ARM_CORE_REG(regs.regs[7]):
+	case KVM_REG_ARM_CORE_REG(regs.pc):
+		return true;
+	}
+	return false;
+}
+
 static int core_reg_size_from_offset(const struct kvm_vcpu *vcpu, u64 off)
 {
 	int size;
@@ -115,6 +126,9 @@ static int core_reg_size_from_offset(const struct kvm_vcpu *vcpu, u64 off)
 	if (vcpu_has_sve(vcpu) && core_reg_offset_is_vreg(off))
 		return -EINVAL;
 
+	if (kvm_is_realm(vcpu->kvm) && !kvm_realm_validate_core_reg(off))
+		return -EPERM;
+
 	return size;
 }
 
@@ -600,8 +614,6 @@ static const u64 timer_reg_list[] = {
 	KVM_REG_ARM_PTIMER_CVAL,
 };
 
-#define NUM_TIMER_REGS ARRAY_SIZE(timer_reg_list)
-
 static bool is_timer_reg(u64 index)
 {
 	switch (index) {
@@ -616,9 +628,14 @@ static bool is_timer_reg(u64 index)
 	return false;
 }
 
+static unsigned long num_timer_regs(struct kvm_vcpu *vcpu)
+{
+	return kvm_is_realm(vcpu->kvm) ? 0 : ARRAY_SIZE(timer_reg_list);
+}
+
 static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
-	for (int i = 0; i < NUM_TIMER_REGS; i++) {
+	for (int i = 0; i < num_timer_regs(vcpu); i++) {
 		if (put_user(timer_reg_list[i], uindices))
 			return -EFAULT;
 		uindices++;
@@ -656,6 +673,9 @@ static unsigned long num_sve_regs(const struct kvm_vcpu *vcpu)
 	if (!vcpu_has_sve(vcpu) || !kvm_arm_vcpu_sve_finalized(vcpu))
 		return 0;
 
+	if (kvm_is_realm(vcpu->kvm))
+		return 1; /* KVM_REG_ARM64_SVE_VLS */
+
 	return slices * (SVE_NUM_PREGS + SVE_NUM_ZREGS + 1 /* FFR */)
 		+ 1; /* KVM_REG_ARM64_SVE_VLS */
 }
@@ -683,6 +703,9 @@ static int copy_sve_reg_indices(const struct kvm_vcpu *vcpu,
 		return -EFAULT;
 	++num_regs;
 
+	if (kvm_is_realm(vcpu->kvm))
+		return num_regs;
+
 	for (i = 0; i < slices; i++) {
 		for (n = 0; n < SVE_NUM_ZREGS; n++) {
 			reg = KVM_REG_ARM64_SVE_ZREG(n, i);
@@ -721,7 +744,7 @@ unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
 	res += num_sve_regs(vcpu);
 	res += kvm_arm_num_sys_reg_descs(vcpu);
 	res += kvm_arm_get_fw_num_regs(vcpu);
-	res += NUM_TIMER_REGS;
+	res += num_timer_regs(vcpu);
 
 	return res;
 }
@@ -755,7 +778,7 @@ int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 	ret = copy_timer_indices(vcpu, uindices);
 	if (ret < 0)
 		return ret;
-	uindices += NUM_TIMER_REGS;
+	uindices += num_timer_regs(vcpu);
 
 	return kvm_arm_copy_sys_reg_indices(vcpu, uindices);
 }
@@ -795,12 +818,7 @@ static bool validate_realm_set_reg(struct kvm_vcpu *vcpu,
 	if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE) {
 		u64 off = core_reg_offset_from_id(reg->id);
 
-		switch (off) {
-		case KVM_REG_ARM_CORE_REG(regs.regs[0]) ...
-		     KVM_REG_ARM_CORE_REG(regs.regs[7]):
-		case KVM_REG_ARM_CORE_REG(regs.pc):
-			return true;
-		}
+		return kvm_realm_validate_core_reg(off);
 	} else {
 		switch (reg->id) {
 		case KVM_REG_ARM_PMCR_EL0:
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5763d979d8ca..28b4166cf234 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -407,14 +407,14 @@ void kvm_arm_teardown_hypercalls(struct kvm *kvm)
 
 int kvm_arm_get_fw_num_regs(struct kvm_vcpu *vcpu)
 {
-	return ARRAY_SIZE(kvm_arm_fw_reg_ids);
+	return kvm_is_realm(vcpu->kvm) ? 0 : ARRAY_SIZE(kvm_arm_fw_reg_ids);
 }
 
 int kvm_arm_copy_fw_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(kvm_arm_fw_reg_ids); i++) {
+	for (i = 0; i < kvm_arm_get_fw_num_regs(vcpu); i++) {
 		if (put_user(kvm_arm_fw_reg_ids[i], uindices++))
 			return -EFAULT;
 	}
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index f92b78039dce..3510c7a684f1 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -4357,18 +4357,18 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg
 				    sys_reg_descs, ARRAY_SIZE(sys_reg_descs));
 }
 
-static unsigned int num_demux_regs(void)
+static unsigned int num_demux_regs(struct kvm_vcpu *vcpu)
 {
-	return CSSELR_MAX;
+	return kvm_is_realm(vcpu->kvm) ? 0 : CSSELR_MAX;
 }
 
-static int write_demux_regids(u64 __user *uindices)
+static int write_demux_regids(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
 	u64 val = KVM_REG_ARM64 | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
 	unsigned int i;
 
 	val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
-	for (i = 0; i < CSSELR_MAX; i++) {
+	for (i = 0; i < num_demux_regs(vcpu); i++) {
 		if (put_user(val | i, uindices))
 			return -EFAULT;
 		uindices++;
@@ -4376,6 +4376,23 @@ static int write_demux_regids(u64 __user *uindices)
 	return 0;
 }
 
+static unsigned int num_invariant_regs(struct kvm_vcpu *vcpu)
+{
+	return kvm_is_realm(vcpu->kvm) ? 0 : ARRAY_SIZE(invariant_sys_regs);
+}
+
+static int write_invariant_regids(struct kvm_vcpu *vcpu, u64 __user *uindices)
+{
+	unsigned int i;
+
+	for (i = 0; i < num_invariant_regs(vcpu); i++) {
+		if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
+			return -EFAULT;
+		uindices++;
+	}
+	return 0;
+}
+
 static u64 sys_reg_to_index(const struct sys_reg_desc *reg)
 {
 	return (KVM_REG_ARM64 | KVM_REG_SIZE_U64 |
@@ -4399,11 +4416,27 @@ static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind)
 	return true;
 }
 
+static bool kvm_realm_sys_reg_hidden_user(const struct kvm_vcpu *vcpu, u64 reg)
+{
+	if (!kvm_is_realm(vcpu->kvm))
+		return false;
+
+	switch (reg) {
+	case SYS_ID_AA64DFR0_EL1:
+	case SYS_PMCR_EL0:
+		return false;
+	}
+	return true;
+}
+
 static int walk_one_sys_reg(const struct kvm_vcpu *vcpu,
 			    const struct sys_reg_desc *rd,
 			    u64 __user **uind,
 			    unsigned int *total)
 {
+	if (kvm_realm_sys_reg_hidden_user(vcpu, reg_to_encoding(rd)))
+		return 0;
+
 	/*
 	 * Ignore registers we trap but don't save,
 	 * and for which no custom user accessor is provided.
@@ -4441,29 +4474,26 @@ static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind)
 
 unsigned long kvm_arm_num_sys_reg_descs(struct kvm_vcpu *vcpu)
 {
-	return ARRAY_SIZE(invariant_sys_regs)
-		+ num_demux_regs()
+	return num_invariant_regs(vcpu)
+		+ num_demux_regs(vcpu)
 		+ walk_sys_regs(vcpu, (u64 __user *)NULL);
 }
 
 int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
-	unsigned int i;
 	int err;
 
-	/* Then give them all the invariant registers' indices. */
-	for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++) {
-		if (put_user(sys_reg_to_index(&invariant_sys_regs[i]), uindices))
-			return -EFAULT;
-		uindices++;
-	}
+	err = write_invariant_regids(vcpu, uindices);
+	if (err)
+		return err;
+	uindices += num_invariant_regs(vcpu);
 
 	err = walk_sys_regs(vcpu, uindices);
 	if (err < 0)
 		return err;
 	uindices += err;
 
-	return write_demux_regids(uindices);
+	return write_demux_regids(vcpu, uindices);
 }
 
 #define KVM_ARM_FEATURE_ID_RANGE_INDEX(r)			\
-- 
2.34.1

[PATCH v4 42/43] arm64: kvm: Expose support for private memory

[Steven Price]

Select KVM_GENERIC_PRIVATE_MEM and provide the necessary support
functions.

Signed-off-by: Steven Price <steven.price@arm.com>
---
Changes since v2:
 * Switch kvm_arch_has_private_mem() to a macro to avoid overhead of a
   function call.
 * Guard definitions of kvm_arch_{pre,post}_set_memory_attributes() with
   #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES.
 * Early out in kvm_arch_post_set_memory_attributes() if the WARN_ON
   should trigger.
---
 arch/arm64/include/asm/kvm_host.h |  6 ++++++
 arch/arm64/kvm/Kconfig            |  1 +
 arch/arm64/kvm/mmu.c              | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 178e02dc4927..a669ff7b0958 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1367,6 +1367,12 @@ struct kvm *kvm_arch_alloc_vm(void);
 
 #define vcpu_is_protected(vcpu)		kvm_vm_is_protected((vcpu)->kvm)
 
+#ifdef CONFIG_KVM_PRIVATE_MEM
+#define kvm_arch_has_private_mem(kvm) ((kvm)->arch.is_realm)
+#else
+#define kvm_arch_has_private_mem(kvm) false
+#endif
+
 int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature);
 bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu);
 
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index 58f09370d17e..8da57e74c86a 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -37,6 +37,7 @@ menuconfig KVM
 	select HAVE_KVM_VCPU_RUN_PID_CHANGE
 	select SCHED_INFO
 	select GUEST_PERF_EVENTS if PERF_EVENTS
+	select KVM_GENERIC_PRIVATE_MEM
 	help
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 2110dd4c18db..c8bfeda9e1e6 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -2284,6 +2284,28 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm,
 	return ret;
 }
 
+#ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
+bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
+					struct kvm_gfn_range *range)
+{
+	WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm));
+	return false;
+}
+
+bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
+					 struct kvm_gfn_range *range)
+{
+	if (WARN_ON_ONCE(!kvm_arch_has_private_mem(kvm)))
+		return false;
+
+	if (range->arg.attributes & KVM_MEMORY_ATTRIBUTE_PRIVATE)
+		range->only_shared = true;
+	kvm_unmap_gfn_range(kvm, range);
+
+	return false;
+}
+#endif
+
 void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
 {
 }
-- 
2.34.1

[PATCH v4 43/43] KVM: arm64: Allow activating realms

[Steven Price]

Add the ioctl to activate a realm and set the static branch to enable
access to the realm functionality if the RMM is detected.

Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/kvm/rme.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
index 9f415411d3b5..1eeef9e15d1c 100644
--- a/arch/arm64/kvm/rme.c
+++ b/arch/arm64/kvm/rme.c
@@ -1194,6 +1194,20 @@ static int kvm_init_ipa_range_realm(struct kvm *kvm,
 	return realm_init_ipa_state(realm, addr, end);
 }
 
+static int kvm_activate_realm(struct kvm *kvm)
+{
+	struct realm *realm = &kvm->arch.realm;
+
+	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
+		return -EINVAL;
+
+	if (rmi_realm_activate(virt_to_phys(realm->rd)))
+		return -ENXIO;
+
+	WRITE_ONCE(realm->state, REALM_STATE_ACTIVE);
+	return 0;
+}
+
 /* Protects access to rme_vmid_bitmap */
 static DEFINE_SPINLOCK(rme_vmid_lock);
 static unsigned long *rme_vmid_bitmap;
@@ -1343,6 +1357,9 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
 		r = kvm_populate_realm(kvm, &args);
 		break;
 	}
+	case KVM_CAP_ARM_RME_ACTIVATE_REALM:
+		r = kvm_activate_realm(kvm);
+		break;
 	default:
 		r = -EINVAL;
 		break;
@@ -1599,5 +1616,5 @@ void kvm_init_rme(void)
 	if (rme_vmid_init())
 		return;
 
-	/* Future patch will enable static branch kvm_rme_is_available */
+	static_branch_enable(&kvm_rme_is_available);
 }
-- 
2.34.1

Re: [PATCH v4 43/43] KVM: arm64: Allow activating realms

[Aneesh Kumar K.V]

Steven Price <steven.price@arm.com> writes:

> Add the ioctl to activate a realm and set the static branch to enable
> access to the realm functionality if the RMM is detected.
>
> Signed-off-by: Steven Price <steven.price@arm.com>
> ---
>  arch/arm64/kvm/rme.c | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
> index 9f415411d3b5..1eeef9e15d1c 100644
> --- a/arch/arm64/kvm/rme.c
> +++ b/arch/arm64/kvm/rme.c
> @@ -1194,6 +1194,20 @@ static int kvm_init_ipa_range_realm(struct kvm *kvm,
>  	return realm_init_ipa_state(realm, addr, end);
>  }
>  
> +static int kvm_activate_realm(struct kvm *kvm)
> +{
> +	struct realm *realm = &kvm->arch.realm;
> +
> +	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
> +		return -EINVAL;
> +
> +	if (rmi_realm_activate(virt_to_phys(realm->rd)))
> +		return -ENXIO;
> +
> +	WRITE_ONCE(realm->state, REALM_STATE_ACTIVE);
> +	return 0;
> +}
> +
>  /* Protects access to rme_vmid_bitmap */
>  static DEFINE_SPINLOCK(rme_vmid_lock);
>  static unsigned long *rme_vmid_bitmap;
> @@ -1343,6 +1357,9 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
>  		r = kvm_populate_realm(kvm, &args);
>  		break;
>  	}
> +	case KVM_CAP_ARM_RME_ACTIVATE_REALM:
> +		r = kvm_activate_realm(kvm);
> +		break;
>  	default:
>  		r = -EINVAL;
>  		break;
> @@ -1599,5 +1616,5 @@ void kvm_init_rme(void)
>  	if (rme_vmid_init())
>  		return;
>  
> -	/* Future patch will enable static branch kvm_rme_is_available */
> +	static_branch_enable(&kvm_rme_is_available);
>

like rsi_present, we might want to use this outside kvm, ex: for TIO.
Can we move this outside module init so that we can have a helper
like is_rme_supported()


-aneesh

Re: [PATCH v4 43/43] KVM: arm64: Allow activating realms

[Steven Price]

On 02/09/2024 06:13, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@arm.com> writes:
> 
>> Add the ioctl to activate a realm and set the static branch to enable
>> access to the realm functionality if the RMM is detected.
>>
>> Signed-off-by: Steven Price <steven.price@arm.com>
>> ---
>>  arch/arm64/kvm/rme.c | 19 ++++++++++++++++++-
>>  1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/kvm/rme.c b/arch/arm64/kvm/rme.c
>> index 9f415411d3b5..1eeef9e15d1c 100644
>> --- a/arch/arm64/kvm/rme.c
>> +++ b/arch/arm64/kvm/rme.c
>> @@ -1194,6 +1194,20 @@ static int kvm_init_ipa_range_realm(struct kvm *kvm,
>>  	return realm_init_ipa_state(realm, addr, end);
>>  }
>>  
>> +static int kvm_activate_realm(struct kvm *kvm)
>> +{
>> +	struct realm *realm = &kvm->arch.realm;
>> +
>> +	if (kvm_realm_state(kvm) != REALM_STATE_NEW)
>> +		return -EINVAL;
>> +
>> +	if (rmi_realm_activate(virt_to_phys(realm->rd)))
>> +		return -ENXIO;
>> +
>> +	WRITE_ONCE(realm->state, REALM_STATE_ACTIVE);
>> +	return 0;
>> +}
>> +
>>  /* Protects access to rme_vmid_bitmap */
>>  static DEFINE_SPINLOCK(rme_vmid_lock);
>>  static unsigned long *rme_vmid_bitmap;
>> @@ -1343,6 +1357,9 @@ int kvm_realm_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
>>  		r = kvm_populate_realm(kvm, &args);
>>  		break;
>>  	}
>> +	case KVM_CAP_ARM_RME_ACTIVATE_REALM:
>> +		r = kvm_activate_realm(kvm);
>> +		break;
>>  	default:
>>  		r = -EINVAL;
>>  		break;
>> @@ -1599,5 +1616,5 @@ void kvm_init_rme(void)
>>  	if (rme_vmid_init())
>>  		return;
>>  
>> -	/* Future patch will enable static branch kvm_rme_is_available */
>> +	static_branch_enable(&kvm_rme_is_available);
>>
> 
> like rsi_present, we might want to use this outside kvm, ex: for TIO.

I'm struggling to think why rme_is_available would be needed outside KVM
- what is "TIO"?

> Can we move this outside module init so that we can have a helper
> like is_rme_supported()

It's obviously possible, but I'm not sure where in the code it would go
- if there is an actual use case outside of KVM then presumably it would
need to move completely outside of the KVM code.

Can you elaborate on why you think it might be useful?

Steve