[PATCH v4 00/18] KVM: arm64: Non-protected guest stage-2 support for pKVM

[PATCH v4 00/18] KVM: arm64: Non-protected guest stage-2 support for pKVM

[Quentin Perret]

Hi all,

This is the v4 of the series adding support for non-protected guests
stage-2 to pKVM. Please refer to v1 for all the context:

  https://lore.kernel.org/kvmarm/20241104133204.85208-1-qperret@google.com/

Please note that in its current form, this series has two main
limitations that will be addressed separately:

 - We don't support mapping devices into guests: this requires
   additional hypervisor support for tracking the 'state' of devices.
   No device assignment until then.

 - Stage-2 mappings are forced to page-granularity even when backed by a
   huge page for the sake of simplicity of this series. I'm only aiming
   at functional parity-ish (from userspace's PoV) for now, support for
   HP can be added on top later as a perf improvement.

The series is organized as follows:

 - Patches 01 to 04 move the host ownership state tracking from the
   host's stage-2 page-table to the hypervisor's vmemmap. This avoids
   fragmenting the host stage-2 for shared pages, which is only needed
   to store an annotation in the SW bits of the corresponding PTE. All
   pages mapped into non-protected guests are shared from pKVM's PoV,
   so the cost of stage-2 fragmentation will increase massively as we
   start tracking that at EL2. Note that these patches also help with
   the existing sharing for e.g. FF-A, so they could possibly be merged
   separately from the rest of the series.

 - Patches 05 to 07 implement a minor refactoring of the pgtable code to
   ease the integration of the pKVM MMU later on.

 - Patches 08 to 16 introduce all the infrastructure needed on the pKVM
   side for handling guest stage-2 page-tables at EL2.

 - Patches 17 and 18 plumb the newly introduced pKVM support into
   KVM/arm64.

Patches based on 6.13-rc3, tested on Pixel 6 and Qemu.

Changes in v4:
 - Collected Tested-by and Reviewed-by tags
 - Reworked KVM_S2_PGT to help ctags/grepping kvm_pgtable_* functions
 - Minor cleanups throughout

Changes in v3:
 - Rebased on 6.13-rc3
 - Applied Marc's rework of the for_each_mapping_in_range() macro mess
 - Removed mappings_lock in favor the mmu_lock
 - Dropped BUG_ON() from pkvm_mkstate()
 - Renamed range_is_allowed_memory() and clarified the comment inside it
 - Explicitly bail out when using host_stage2_set_owner_locked() on
   non-memory regions
 - Check PKVM_NOPAGE state as an equality rather than a bitwise
   operator
 - Reworked __pkvm_host_share_guest() to return -EPERM in case of
   illegal multi-sharing
 - Added get_np_pkvm_hyp_vm() to simplify HVC error handling in
   hyp-main.c
 - Cosmetic changes and improved coding consitency thoughout the series

Changes in v2:
 - Rebased on 6.13-rc1 (small conflicts with commit 2362506f7cff ("KVM:
   arm64: Don't mark "struct page" accessed when making SPTE young") in
   particular)
 - Fixed kerneldoc breakage for __unmap_stage2_range()
 - Fixed pkvm_pgtable_test_clear_young() to use correct HVC
 - Folded guest_get_valid_pte() into __check_host_unshare_guest() for
   clarity

Thanks,
Quentin

Marc Zyngier (1):
  KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

Quentin Perret (17):
  KVM: arm64: Change the layout of enum pkvm_page_state
  KVM: arm64: Move enum pkvm_page_state to memory.h
  KVM: arm64: Make hyp_page::order a u8
  KVM: arm64: Move host page ownership tracking to the hyp vmemmap
  KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung
  KVM: arm64: Pass walk flags to kvm_pgtable_stage2_relax_perms
  KVM: arm64: Make kvm_pgtable_stage2_init() a static inline function
  KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers
  KVM: arm64: Introduce __pkvm_host_share_guest()
  KVM: arm64: Introduce __pkvm_host_unshare_guest()
  KVM: arm64: Introduce __pkvm_host_relax_guest_perms()
  KVM: arm64: Introduce __pkvm_host_wrprotect_guest()
  KVM: arm64: Introduce __pkvm_host_test_clear_young_guest()
  KVM: arm64: Introduce __pkvm_host_mkyoung_guest()
  KVM: arm64: Introduce __pkvm_tlb_flush_vmid()
  KVM: arm64: Introduce the EL1 pKVM MMU
  KVM: arm64: Plumb the pKVM MMU in KVM

 arch/arm64/include/asm/kvm_asm.h              |   9 +
 arch/arm64/include/asm/kvm_host.h             |   4 +
 arch/arm64/include/asm/kvm_mmu.h              |  16 +
 arch/arm64/include/asm/kvm_pgtable.h          |  38 ++-
 arch/arm64/include/asm/kvm_pkvm.h             |  26 ++
 arch/arm64/kvm/arm.c                          |  23 +-
 arch/arm64/kvm/hyp/include/nvhe/gfp.h         |   6 +-
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  39 +--
 arch/arm64/kvm/hyp/include/nvhe/memory.h      |  50 ++-
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h        |  16 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 201 ++++++++++-
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 320 ++++++++++++++++--
 arch/arm64/kvm/hyp/nvhe/page_alloc.c          |  14 +-
 arch/arm64/kvm/hyp/nvhe/pkvm.c                |  69 ++++
 arch/arm64/kvm/hyp/nvhe/setup.c               |   7 +-
 arch/arm64/kvm/hyp/pgtable.c                  |  13 +-
 arch/arm64/kvm/mmu.c                          |  93 +++--
 arch/arm64/kvm/pkvm.c                         | 201 +++++++++++
 arch/arm64/kvm/vgic/vgic-v3.c                 |   6 +-
 19 files changed, 1006 insertions(+), 145 deletions(-)

-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 01/18] KVM: arm64: Change the layout of enum pkvm_page_state

[Quentin Perret]

The 'concrete' (a.k.a non-meta) page states are currently encoded using
software bits in PTEs. For performance reasons, the abstract
pkvm_page_state enum uses the same bits to encode these states as that
makes conversions from and to PTEs easy.

In order to prepare the ground for moving the 'concrete' state storage
to the hyp vmemmap, re-arrange the enum to use bits 0 and 1 for this
purpose.

No functional changes intended.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 0972faccc2af..5462faf6bfee 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -24,25 +24,27 @@
  */
 enum pkvm_page_state {
 	PKVM_PAGE_OWNED			= 0ULL,
-	PKVM_PAGE_SHARED_OWNED		= KVM_PGTABLE_PROT_SW0,
-	PKVM_PAGE_SHARED_BORROWED	= KVM_PGTABLE_PROT_SW1,
-	__PKVM_PAGE_RESERVED		= KVM_PGTABLE_PROT_SW0 |
-					  KVM_PGTABLE_PROT_SW1,
+	PKVM_PAGE_SHARED_OWNED		= BIT(0),
+	PKVM_PAGE_SHARED_BORROWED	= BIT(1),
+	__PKVM_PAGE_RESERVED		= BIT(0) | BIT(1),
 
 	/* Meta-states which aren't encoded directly in the PTE's SW bits */
-	PKVM_NOPAGE,
+	PKVM_NOPAGE			= BIT(2),
 };
+#define PKVM_PAGE_META_STATES_MASK	(~__PKVM_PAGE_RESERVED)
 
 #define PKVM_PAGE_STATE_PROT_MASK	(KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)
 static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,
 						 enum pkvm_page_state state)
 {
-	return (prot & ~PKVM_PAGE_STATE_PROT_MASK) | state;
+	prot &= ~PKVM_PAGE_STATE_PROT_MASK;
+	prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state);
+	return prot;
 }
 
 static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
 {
-	return prot & PKVM_PAGE_STATE_PROT_MASK;
+	return FIELD_GET(PKVM_PAGE_STATE_PROT_MASK, prot);
 }
 
 struct host_mmu {
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 02/18] KVM: arm64: Move enum pkvm_page_state to memory.h

[Quentin Perret]

In order to prepare the way for storing page-tracking information in
pKVM's vmemmap, move the enum pkvm_page_state definition to
nvhe/memory.h.

No functional changes intended.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 34 +------------------
 arch/arm64/kvm/hyp/include/nvhe/memory.h      | 33 ++++++++++++++++++
 2 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 5462faf6bfee..25038ac705d8 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -11,42 +11,10 @@
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
 #include <asm/virt.h>
+#include <nvhe/memory.h>
 #include <nvhe/pkvm.h>
 #include <nvhe/spinlock.h>
 
-/*
- * SW bits 0-1 are reserved to track the memory ownership state of each page:
- *   00: The page is owned exclusively by the page-table owner.
- *   01: The page is owned by the page-table owner, but is shared
- *       with another entity.
- *   10: The page is shared with, but not owned by the page-table owner.
- *   11: Reserved for future use (lending).
- */
-enum pkvm_page_state {
-	PKVM_PAGE_OWNED			= 0ULL,
-	PKVM_PAGE_SHARED_OWNED		= BIT(0),
-	PKVM_PAGE_SHARED_BORROWED	= BIT(1),
-	__PKVM_PAGE_RESERVED		= BIT(0) | BIT(1),
-
-	/* Meta-states which aren't encoded directly in the PTE's SW bits */
-	PKVM_NOPAGE			= BIT(2),
-};
-#define PKVM_PAGE_META_STATES_MASK	(~__PKVM_PAGE_RESERVED)
-
-#define PKVM_PAGE_STATE_PROT_MASK	(KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)
-static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,
-						 enum pkvm_page_state state)
-{
-	prot &= ~PKVM_PAGE_STATE_PROT_MASK;
-	prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state);
-	return prot;
-}
-
-static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
-{
-	return FIELD_GET(PKVM_PAGE_STATE_PROT_MASK, prot);
-}
-
 struct host_mmu {
 	struct kvm_arch arch;
 	struct kvm_pgtable pgt;
diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index ab205c4d6774..0964c461da92 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -7,6 +7,39 @@
 
 #include <linux/types.h>
 
+/*
+ * SW bits 0-1 are reserved to track the memory ownership state of each page:
+ *   00: The page is owned exclusively by the page-table owner.
+ *   01: The page is owned by the page-table owner, but is shared
+ *       with another entity.
+ *   10: The page is shared with, but not owned by the page-table owner.
+ *   11: Reserved for future use (lending).
+ */
+enum pkvm_page_state {
+	PKVM_PAGE_OWNED			= 0ULL,
+	PKVM_PAGE_SHARED_OWNED		= BIT(0),
+	PKVM_PAGE_SHARED_BORROWED	= BIT(1),
+	__PKVM_PAGE_RESERVED		= BIT(0) | BIT(1),
+
+	/* Meta-states which aren't encoded directly in the PTE's SW bits */
+	PKVM_NOPAGE			= BIT(2),
+};
+#define PKVM_PAGE_META_STATES_MASK	(~__PKVM_PAGE_RESERVED)
+
+#define PKVM_PAGE_STATE_PROT_MASK	(KVM_PGTABLE_PROT_SW0 | KVM_PGTABLE_PROT_SW1)
+static inline enum kvm_pgtable_prot pkvm_mkstate(enum kvm_pgtable_prot prot,
+						 enum pkvm_page_state state)
+{
+	prot &= ~PKVM_PAGE_STATE_PROT_MASK;
+	prot |= FIELD_PREP(PKVM_PAGE_STATE_PROT_MASK, state);
+	return prot;
+}
+
+static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
+{
+	return FIELD_GET(PKVM_PAGE_STATE_PROT_MASK, prot);
+}
+
 struct hyp_page {
 	unsigned short refcount;
 	unsigned short order;
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 03/18] KVM: arm64: Make hyp_page::order a u8

[Quentin Perret]

We don't need 16 bits to store the hyp page order, and we'll need some
bits to store page ownership data soon, so let's reduce the order
member.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/gfp.h    |  6 +++---
 arch/arm64/kvm/hyp/include/nvhe/memory.h |  5 +++--
 arch/arm64/kvm/hyp/nvhe/page_alloc.c     | 14 +++++++-------
 3 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index 97c527ef53c2..3766333bace9 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
@@ -7,7 +7,7 @@
 #include <nvhe/memory.h>
 #include <nvhe/spinlock.h>
 
-#define HYP_NO_ORDER	USHRT_MAX
+#define HYP_NO_ORDER	((u8)(~0))
 
 struct hyp_pool {
 	/*
@@ -19,11 +19,11 @@ struct hyp_pool {
 	struct list_head free_area[NR_PAGE_ORDERS];
 	phys_addr_t range_start;
 	phys_addr_t range_end;
-	unsigned short max_order;
+	u8 max_order;
 };
 
 /* Allocation */
-void *hyp_alloc_pages(struct hyp_pool *pool, unsigned short order);
+void *hyp_alloc_pages(struct hyp_pool *pool, u8 order);
 void hyp_split_page(struct hyp_page *page);
 void hyp_get_page(struct hyp_pool *pool, void *addr);
 void hyp_put_page(struct hyp_pool *pool, void *addr);
diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index 0964c461da92..8f2b42bcc8e1 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -41,8 +41,9 @@ static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
 }
 
 struct hyp_page {
-	unsigned short refcount;
-	unsigned short order;
+	u16 refcount;
+	u8 order;
+	u8 reserved;
 };
 
 extern u64 __hyp_vmemmap;
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index e691290d3765..a1eb27a1a747 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -32,7 +32,7 @@ u64 __hyp_vmemmap;
  */
 static struct hyp_page *__find_buddy_nocheck(struct hyp_pool *pool,
 					     struct hyp_page *p,
-					     unsigned short order)
+					     u8 order)
 {
 	phys_addr_t addr = hyp_page_to_phys(p);
 
@@ -51,7 +51,7 @@ static struct hyp_page *__find_buddy_nocheck(struct hyp_pool *pool,
 /* Find a buddy page currently available for allocation */
 static struct hyp_page *__find_buddy_avail(struct hyp_pool *pool,
 					   struct hyp_page *p,
-					   unsigned short order)
+					   u8 order)
 {
 	struct hyp_page *buddy = __find_buddy_nocheck(pool, p, order);
 
@@ -94,7 +94,7 @@ static void __hyp_attach_page(struct hyp_pool *pool,
 			      struct hyp_page *p)
 {
 	phys_addr_t phys = hyp_page_to_phys(p);
-	unsigned short order = p->order;
+	u8 order = p->order;
 	struct hyp_page *buddy;
 
 	memset(hyp_page_to_virt(p), 0, PAGE_SIZE << p->order);
@@ -129,7 +129,7 @@ static void __hyp_attach_page(struct hyp_pool *pool,
 
 static struct hyp_page *__hyp_extract_page(struct hyp_pool *pool,
 					   struct hyp_page *p,
-					   unsigned short order)
+					   u8 order)
 {
 	struct hyp_page *buddy;
 
@@ -183,7 +183,7 @@ void hyp_get_page(struct hyp_pool *pool, void *addr)
 
 void hyp_split_page(struct hyp_page *p)
 {
-	unsigned short order = p->order;
+	u8 order = p->order;
 	unsigned int i;
 
 	p->order = 0;
@@ -195,10 +195,10 @@ void hyp_split_page(struct hyp_page *p)
 	}
 }
 
-void *hyp_alloc_pages(struct hyp_pool *pool, unsigned short order)
+void *hyp_alloc_pages(struct hyp_pool *pool, u8 order)
 {
-	unsigned short i = order;
 	struct hyp_page *p;
+	u8 i = order;
 
 	hyp_spin_lock(&pool->lock);
 
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 04/18] KVM: arm64: Move host page ownership tracking to the hyp vmemmap

[Quentin Perret]

We currently store part of the page-tracking state in PTE software bits
for the host, guests and the hypervisor. This is sub-optimal when e.g.
sharing pages as this forces to break block mappings purely to support
this software tracking. This causes an unnecessarily fragmented stage-2
page-table for the host in particular when it shares pages with Secure,
which can lead to measurable regressions. Moreover, having this state
stored in the page-table forces us to do multiple costly walks on the
page transition path, hence causing overhead.

In order to work around these problems, move the host-side page-tracking
logic from SW bits in its stage-2 PTEs to the hypervisor's vmemmap.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/memory.h |  14 +++-
 arch/arm64/kvm/hyp/nvhe/mem_protect.c    | 100 ++++++++++++++++-------
 arch/arm64/kvm/hyp/nvhe/setup.c          |   7 +-
 3 files changed, 84 insertions(+), 37 deletions(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index 8f2b42bcc8e1..2a5eabf4b753 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -8,7 +8,7 @@
 #include <linux/types.h>
 
 /*
- * SW bits 0-1 are reserved to track the memory ownership state of each page:
+ * Bits 0-1 are reserved to track the memory ownership state of each page:
  *   00: The page is owned exclusively by the page-table owner.
  *   01: The page is owned by the page-table owner, but is shared
  *       with another entity.
@@ -43,7 +43,9 @@ static inline enum pkvm_page_state pkvm_getstate(enum kvm_pgtable_prot prot)
 struct hyp_page {
 	u16 refcount;
 	u8 order;
-	u8 reserved;
+
+	/* Host (non-meta) state. Guarded by the host stage-2 lock. */
+	enum pkvm_page_state host_state : 8;
 };
 
 extern u64 __hyp_vmemmap;
@@ -63,7 +65,13 @@ static inline phys_addr_t hyp_virt_to_phys(void *addr)
 
 #define hyp_phys_to_pfn(phys)	((phys) >> PAGE_SHIFT)
 #define hyp_pfn_to_phys(pfn)	((phys_addr_t)((pfn) << PAGE_SHIFT))
-#define hyp_phys_to_page(phys)	(&hyp_vmemmap[hyp_phys_to_pfn(phys)])
+
+static inline struct hyp_page *hyp_phys_to_page(phys_addr_t phys)
+{
+	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u32));
+	return &hyp_vmemmap[hyp_phys_to_pfn(phys)];
+}
+
 #define hyp_virt_to_page(virt)	hyp_phys_to_page(__hyp_pa(virt))
 #define hyp_virt_to_pfn(virt)	hyp_phys_to_pfn(__hyp_pa(virt))
 
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index caba3e4bd09e..12bb5445fe47 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -201,8 +201,8 @@ static void *guest_s2_zalloc_page(void *mc)
 
 	memset(addr, 0, PAGE_SIZE);
 	p = hyp_virt_to_page(addr);
-	memset(p, 0, sizeof(*p));
 	p->refcount = 1;
+	p->order = 0;
 
 	return addr;
 }
@@ -268,6 +268,7 @@ int kvm_guest_prepare_stage2(struct pkvm_hyp_vm *vm, void *pgd)
 
 void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc)
 {
+	struct hyp_page *page;
 	void *addr;
 
 	/* Dump all pgtable pages in the hyp_pool */
@@ -279,7 +280,9 @@ void reclaim_guest_pages(struct pkvm_hyp_vm *vm, struct kvm_hyp_memcache *mc)
 	/* Drain the hyp_pool into the memcache */
 	addr = hyp_alloc_pages(&vm->pool, 0);
 	while (addr) {
-		memset(hyp_virt_to_page(addr), 0, sizeof(struct hyp_page));
+		page = hyp_virt_to_page(addr);
+		page->refcount = 0;
+		page->order = 0;
 		push_hyp_memcache(mc, addr, hyp_virt_to_phys);
 		WARN_ON(__pkvm_hyp_donate_host(hyp_virt_to_pfn(addr), 1));
 		addr = hyp_alloc_pages(&vm->pool, 0);
@@ -382,19 +385,28 @@ bool addr_is_memory(phys_addr_t phys)
 	return !!find_mem_range(phys, &range);
 }
 
-static bool addr_is_allowed_memory(phys_addr_t phys)
+static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)
+{
+	return range->start <= addr && addr < range->end;
+}
+
+static int check_range_allowed_memory(u64 start, u64 end)
 {
 	struct memblock_region *reg;
 	struct kvm_mem_range range;
 
-	reg = find_mem_range(phys, &range);
+	/*
+	 * Callers can't check the state of a range that overlaps memory and
+	 * MMIO regions, so ensure [start, end[ is in the same kvm_mem_range.
+	 */
+	reg = find_mem_range(start, &range);
+	if (!is_in_mem_range(end - 1, &range))
+		return -EINVAL;
 
-	return reg && !(reg->flags & MEMBLOCK_NOMAP);
-}
+	if (!reg || reg->flags & MEMBLOCK_NOMAP)
+		return -EPERM;
 
-static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)
-{
-	return range->start <= addr && addr < range->end;
+	return 0;
 }
 
 static bool range_is_memory(u64 start, u64 end)
@@ -454,8 +466,10 @@ static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
 	if (kvm_pte_valid(pte))
 		return -EAGAIN;
 
-	if (pte)
+	if (pte) {
+		WARN_ON(addr_is_memory(addr) && hyp_phys_to_page(addr)->host_state != PKVM_NOPAGE);
 		return -EPERM;
+	}
 
 	do {
 		u64 granule = kvm_granule_size(level);
@@ -477,10 +491,33 @@ int host_stage2_idmap_locked(phys_addr_t addr, u64 size,
 	return host_stage2_try(__host_stage2_idmap, addr, addr + size, prot);
 }
 
+static void __host_update_page_state(phys_addr_t addr, u64 size, enum pkvm_page_state state)
+{
+	phys_addr_t end = addr + size;
+
+	for (; addr < end; addr += PAGE_SIZE)
+		hyp_phys_to_page(addr)->host_state = state;
+}
+
 int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
 {
-	return host_stage2_try(kvm_pgtable_stage2_set_owner, &host_mmu.pgt,
-			       addr, size, &host_s2_pool, owner_id);
+	int ret;
+
+	if (!addr_is_memory(addr))
+		return -EPERM;
+
+	ret = host_stage2_try(kvm_pgtable_stage2_set_owner, &host_mmu.pgt,
+			      addr, size, &host_s2_pool, owner_id);
+	if (ret)
+		return ret;
+
+	/* Don't forget to update the vmemmap tracking for the host */
+	if (owner_id == PKVM_ID_HOST)
+		__host_update_page_state(addr, size, PKVM_PAGE_OWNED);
+	else
+		__host_update_page_state(addr, size, PKVM_NOPAGE);
+
+	return 0;
 }
 
 static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot)
@@ -604,35 +641,38 @@ static int check_page_state_range(struct kvm_pgtable *pgt, u64 addr, u64 size,
 	return kvm_pgtable_walk(pgt, addr, size, &walker);
 }
 
-static enum pkvm_page_state host_get_page_state(kvm_pte_t pte, u64 addr)
-{
-	if (!addr_is_allowed_memory(addr))
-		return PKVM_NOPAGE;
-
-	if (!kvm_pte_valid(pte) && pte)
-		return PKVM_NOPAGE;
-
-	return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
-}
-
 static int __host_check_page_state_range(u64 addr, u64 size,
 					 enum pkvm_page_state state)
 {
-	struct check_walk_data d = {
-		.desired	= state,
-		.get_page_state	= host_get_page_state,
-	};
+	u64 end = addr + size;
+	int ret;
+
+	ret = check_range_allowed_memory(addr, end);
+	if (ret)
+		return ret;
 
 	hyp_assert_lock_held(&host_mmu.lock);
-	return check_page_state_range(&host_mmu.pgt, addr, size, &d);
+	for (; addr < end; addr += PAGE_SIZE) {
+		if (hyp_phys_to_page(addr)->host_state != state)
+			return -EPERM;
+	}
+
+	return 0;
 }
 
 static int __host_set_page_state_range(u64 addr, u64 size,
 				       enum pkvm_page_state state)
 {
-	enum kvm_pgtable_prot prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, state);
+	if (hyp_phys_to_page(addr)->host_state == PKVM_NOPAGE) {
+		int ret = host_stage2_idmap_locked(addr, size, PKVM_HOST_MEM_PROT);
 
-	return host_stage2_idmap_locked(addr, size, prot);
+		if (ret)
+			return ret;
+	}
+
+	__host_update_page_state(addr, size, state);
+
+	return 0;
 }
 
 static int host_request_owned_transition(u64 *completer_addr,
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index cbdd18cd3f98..7e04d1c2a03d 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -180,7 +180,6 @@ static void hpool_put_page(void *addr)
 static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
 				     enum kvm_pgtable_walk_flags visit)
 {
-	enum kvm_pgtable_prot prot;
 	enum pkvm_page_state state;
 	phys_addr_t phys;
 
@@ -203,16 +202,16 @@ static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
 	case PKVM_PAGE_OWNED:
 		return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
 	case PKVM_PAGE_SHARED_OWNED:
-		prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
+		hyp_phys_to_page(phys)->host_state = PKVM_PAGE_SHARED_BORROWED;
 		break;
 	case PKVM_PAGE_SHARED_BORROWED:
-		prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
+		hyp_phys_to_page(phys)->host_state = PKVM_PAGE_SHARED_OWNED;
 		break;
 	default:
 		return -EINVAL;
 	}
 
-	return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
+	return 0;
 }
 
 static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx,
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 05/18] KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung

[Quentin Perret]

kvm_pgtable_stage2_mkyoung currently assumes that it is being called
from a 'shared' walker, which will not be true once called from pKVM.
To allow for the re-use of that function, make the walk flags one of
its parameters.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 4 +++-
 arch/arm64/kvm/hyp/pgtable.c         | 7 +++----
 arch/arm64/kvm/mmu.c                 | 3 ++-
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index aab04097b505..38b7ec1c8614 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -669,13 +669,15 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
  * kvm_pgtable_stage2_mkyoung() - Set the access flag in a page-table entry.
  * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
  * @addr:	Intermediate physical address to identify the page-table entry.
+ * @flags:	Flags to control the page-table walk (ex. a shared walk)
  *
  * The offset of @addr within a page is ignored.
  *
  * If there is a valid, leaf page-table entry used to translate @addr, then
  * set the access flag in that entry.
  */
-void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr);
+void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
+				enum kvm_pgtable_walk_flags flags);
 
 /**
  * kvm_pgtable_stage2_test_clear_young() - Test and optionally clear the access
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 40bd55966540..0470aedb4bf4 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1245,14 +1245,13 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
 					NULL, NULL, 0);
 }
 
-void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
+void kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
+				enum kvm_pgtable_walk_flags flags)
 {
 	int ret;
 
 	ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
-				       NULL, NULL,
-				       KVM_PGTABLE_WALK_HANDLE_FAULT |
-				       KVM_PGTABLE_WALK_SHARED);
+				       NULL, NULL, flags);
 	if (!ret)
 		dsb(ishst);
 }
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index c9d46ad57e52..a2339b76c826 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1718,13 +1718,14 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 /* Resolve the access fault by making the page young again. */
 static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
 {
+	enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED;
 	struct kvm_s2_mmu *mmu;
 
 	trace_kvm_access_fault(fault_ipa);
 
 	read_lock(&vcpu->kvm->mmu_lock);
 	mmu = vcpu->arch.hw_mmu;
-	kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
+	kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa, flags);
 	read_unlock(&vcpu->kvm->mmu_lock);
 }
 
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 06/18] KVM: arm64: Pass walk flags to kvm_pgtable_stage2_relax_perms

[Quentin Perret]

kvm_pgtable_stage2_relax_perms currently assumes that it is being called
from a 'shared' walker, which will not be true once called from pKVM. To
allow for the re-use of that function, make the walk flags one of its
parameters.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 4 +++-
 arch/arm64/kvm/hyp/pgtable.c         | 6 ++----
 arch/arm64/kvm/mmu.c                 | 7 +++----
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 38b7ec1c8614..c2f4149283ef 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -707,6 +707,7 @@ bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr,
  * @pgt:	Page-table structure initialised by kvm_pgtable_stage2_init*().
  * @addr:	Intermediate physical address to identify the page-table entry.
  * @prot:	Additional permissions to grant for the mapping.
+ * @flags:	Flags to control the page-table walk (ex. a shared walk)
  *
  * The offset of @addr within a page is ignored.
  *
@@ -719,7 +720,8 @@ bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr,
  * Return: 0 on success, negative error code on failure.
  */
 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
-				   enum kvm_pgtable_prot prot);
+				   enum kvm_pgtable_prot prot,
+				   enum kvm_pgtable_walk_flags flags);
 
 /**
  * kvm_pgtable_stage2_flush_range() - Clean and invalidate data cache to Point
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 0470aedb4bf4..b7a3b5363235 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1307,7 +1307,7 @@ bool kvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr,
 }
 
 int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
-				   enum kvm_pgtable_prot prot)
+				   enum kvm_pgtable_prot prot, enum kvm_pgtable_walk_flags flags)
 {
 	int ret;
 	s8 level;
@@ -1325,9 +1325,7 @@ int kvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr,
 	if (prot & KVM_PGTABLE_PROT_X)
 		clr |= KVM_PTE_LEAF_ATTR_HI_S2_XN;
 
-	ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level,
-				       KVM_PGTABLE_WALK_HANDLE_FAULT |
-				       KVM_PGTABLE_WALK_SHARED);
+	ret = stage2_update_leaf_attrs(pgt, addr, 1, set, clr, NULL, &level, flags);
 	if (!ret || ret == -EAGAIN)
 		kvm_call_hyp(__kvm_tlb_flush_vmid_ipa_nsh, pgt->mmu, addr, level);
 	return ret;
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a2339b76c826..641e4fec1659 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1452,6 +1452,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
 	struct kvm_pgtable *pgt;
 	struct page *page;
+	enum kvm_pgtable_walk_flags flags = KVM_PGTABLE_WALK_HANDLE_FAULT | KVM_PGTABLE_WALK_SHARED;
 
 	if (fault_is_perm)
 		fault_granule = kvm_vcpu_trap_get_perm_fault_granule(vcpu);
@@ -1695,13 +1696,11 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		 * PTE, which will be preserved.
 		 */
 		prot &= ~KVM_NV_GUEST_MAP_SZ;
-		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
+		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot, flags);
 	} else {
 		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
 					     __pfn_to_phys(pfn), prot,
-					     memcache,
-					     KVM_PGTABLE_WALK_HANDLE_FAULT |
-					     KVM_PGTABLE_WALK_SHARED);
+					     memcache, flags);
 	}
 
 out_unlock:
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 07/18] KVM: arm64: Make kvm_pgtable_stage2_init() a static inline function

[Quentin Perret]

Turn kvm_pgtable_stage2_init() into a static inline function instead of
a macro. This will allow the usage of typeof() on it later on.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_pgtable.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index c2f4149283ef..04418b5e3004 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -526,8 +526,11 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
 			      enum kvm_pgtable_stage2_flags flags,
 			      kvm_pgtable_force_pte_cb_t force_pte_cb);
 
-#define kvm_pgtable_stage2_init(pgt, mmu, mm_ops) \
-	__kvm_pgtable_stage2_init(pgt, mmu, mm_ops, 0, NULL)
+static inline int kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
+					  struct kvm_pgtable_mm_ops *mm_ops)
+{
+	return __kvm_pgtable_stage2_init(pgt, mmu, mm_ops, 0, NULL);
+}
 
 /**
  * kvm_pgtable_stage2_destroy() - Destroy an unused guest stage-2 page-table.
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 08/18] KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers

[Quentin Perret]

In preparation for accessing pkvm_hyp_vm structures at EL2 in a context
where we can't always expect a vCPU to be loaded (e.g. MMU notifiers),
introduce get/put helpers to get temporary references to hyp VMs from
any context.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h |  3 +++
 arch/arm64/kvm/hyp/nvhe/pkvm.c         | 20 ++++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index 24a9a8330d19..f361d8b91930 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -70,4 +70,7 @@ struct pkvm_hyp_vcpu *pkvm_load_hyp_vcpu(pkvm_handle_t handle,
 					 unsigned int vcpu_idx);
 void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu);
 
+struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle);
+void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm);
+
 #endif /* __ARM64_KVM_NVHE_PKVM_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 071993c16de8..d46a02e24e4a 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -327,6 +327,26 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	hyp_spin_unlock(&vm_table_lock);
 }
 
+struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle)
+{
+	struct pkvm_hyp_vm *hyp_vm;
+
+	hyp_spin_lock(&vm_table_lock);
+	hyp_vm = get_vm_by_handle(handle);
+	if (hyp_vm)
+		hyp_page_ref_inc(hyp_virt_to_page(hyp_vm));
+	hyp_spin_unlock(&vm_table_lock);
+
+	return hyp_vm;
+}
+
+void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm)
+{
+	hyp_spin_lock(&vm_table_lock);
+	hyp_page_ref_dec(hyp_virt_to_page(hyp_vm));
+	hyp_spin_unlock(&vm_table_lock);
+}
+
 static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struct kvm *host_kvm)
 {
 	struct kvm *kvm = &hyp_vm->kvm;
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[Quentin Perret]

From: Marc Zyngier <maz@kernel.org>

Rather than look-up the hyp vCPU on every run hypercall at EL2,
introduce a per-CPU 'loaded_hyp_vcpu' tracking variable which is updated
by a pair of load/put hypercalls called directly from
kvm_arch_vcpu_{load,put}() when pKVM is enabled.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h       |  2 ++
 arch/arm64/kvm/arm.c                   | 14 ++++++++
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h |  7 ++++
 arch/arm64/kvm/hyp/nvhe/hyp-main.c     | 47 ++++++++++++++++++++------
 arch/arm64/kvm/hyp/nvhe/pkvm.c         | 29 ++++++++++++++++
 arch/arm64/kvm/vgic/vgic-v3.c          |  6 ++--
 6 files changed, 93 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index ca2590344313..89c0fac69551 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -79,6 +79,8 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_init_vm,
 	__KVM_HOST_SMCCC_FUNC___pkvm_init_vcpu,
 	__KVM_HOST_SMCCC_FUNC___pkvm_teardown_vm,
+	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_load,
+	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_put,
 };
 
 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index a102c3aebdbc..55cc62b2f469 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -619,12 +619,26 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 
 	kvm_arch_vcpu_load_debug_state_flags(vcpu);
 
+	if (is_protected_kvm_enabled()) {
+		kvm_call_hyp_nvhe(__pkvm_vcpu_load,
+				  vcpu->kvm->arch.pkvm.handle,
+				  vcpu->vcpu_idx, vcpu->arch.hcr_el2);
+		kvm_call_hyp(__vgic_v3_restore_vmcr_aprs,
+			     &vcpu->arch.vgic_cpu.vgic_v3);
+	}
+
 	if (!cpumask_test_cpu(cpu, vcpu->kvm->arch.supported_cpus))
 		vcpu_set_on_unsupported_cpu(vcpu);
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+	if (is_protected_kvm_enabled()) {
+		kvm_call_hyp(__vgic_v3_save_vmcr_aprs,
+			     &vcpu->arch.vgic_cpu.vgic_v3);
+		kvm_call_hyp_nvhe(__pkvm_vcpu_put);
+	}
+
 	kvm_arch_vcpu_put_debug_state_flags(vcpu);
 	kvm_arch_vcpu_put_fp(vcpu);
 	if (has_vhe())
diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index f361d8b91930..be52c5b15e21 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -20,6 +20,12 @@ struct pkvm_hyp_vcpu {
 
 	/* Backpointer to the host's (untrusted) vCPU instance. */
 	struct kvm_vcpu *host_vcpu;
+
+	/*
+	 * If this hyp vCPU is loaded, then this is a backpointer to the
+	 * per-cpu pointer tracking us. Otherwise, NULL if not loaded.
+	 */
+	struct pkvm_hyp_vcpu **loaded_hyp_vcpu;
 };
 
 /*
@@ -69,6 +75,7 @@ int __pkvm_teardown_vm(pkvm_handle_t handle);
 struct pkvm_hyp_vcpu *pkvm_load_hyp_vcpu(pkvm_handle_t handle,
 					 unsigned int vcpu_idx);
 void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu);
+struct pkvm_hyp_vcpu *pkvm_get_loaded_hyp_vcpu(void);
 
 struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle);
 void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 6aa0b13d86e5..95d78db315b3 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -141,16 +141,46 @@ static void sync_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 		host_cpu_if->vgic_lr[i] = hyp_cpu_if->vgic_lr[i];
 }
 
+static void handle___pkvm_vcpu_load(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	DECLARE_REG(unsigned int, vcpu_idx, host_ctxt, 2);
+	DECLARE_REG(u64, hcr_el2, host_ctxt, 3);
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+
+	if (!is_protected_kvm_enabled())
+		return;
+
+	hyp_vcpu = pkvm_load_hyp_vcpu(handle, vcpu_idx);
+	if (!hyp_vcpu)
+		return;
+
+	if (pkvm_hyp_vcpu_is_protected(hyp_vcpu)) {
+		/* Propagate WFx trapping flags */
+		hyp_vcpu->vcpu.arch.hcr_el2 &= ~(HCR_TWE | HCR_TWI);
+		hyp_vcpu->vcpu.arch.hcr_el2 |= hcr_el2 & (HCR_TWE | HCR_TWI);
+	}
+}
+
+static void handle___pkvm_vcpu_put(struct kvm_cpu_context *host_ctxt)
+{
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+
+	if (!is_protected_kvm_enabled())
+		return;
+
+	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();
+	if (hyp_vcpu)
+		pkvm_put_hyp_vcpu(hyp_vcpu);
+}
+
 static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, host_vcpu, host_ctxt, 1);
 	int ret;
 
-	host_vcpu = kern_hyp_va(host_vcpu);
-
 	if (unlikely(is_protected_kvm_enabled())) {
-		struct pkvm_hyp_vcpu *hyp_vcpu;
-		struct kvm *host_kvm;
+		struct pkvm_hyp_vcpu *hyp_vcpu = pkvm_get_loaded_hyp_vcpu();
 
 		/*
 		 * KVM (and pKVM) doesn't support SME guests for now, and
@@ -163,9 +193,6 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
 			goto out;
 		}
 
-		host_kvm = kern_hyp_va(host_vcpu->kvm);
-		hyp_vcpu = pkvm_load_hyp_vcpu(host_kvm->arch.pkvm.handle,
-					      host_vcpu->vcpu_idx);
 		if (!hyp_vcpu) {
 			ret = -EINVAL;
 			goto out;
@@ -176,12 +203,10 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
 		ret = __kvm_vcpu_run(&hyp_vcpu->vcpu);
 
 		sync_hyp_vcpu(hyp_vcpu);
-		pkvm_put_hyp_vcpu(hyp_vcpu);
 	} else {
 		/* The host is fully trusted, run its vCPU directly. */
-		ret = __kvm_vcpu_run(host_vcpu);
+		ret = __kvm_vcpu_run(kern_hyp_va(host_vcpu));
 	}
-
 out:
 	cpu_reg(host_ctxt, 1) =  ret;
 }
@@ -409,6 +434,8 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_init_vm),
 	HANDLE_FUNC(__pkvm_init_vcpu),
 	HANDLE_FUNC(__pkvm_teardown_vm),
+	HANDLE_FUNC(__pkvm_vcpu_load),
+	HANDLE_FUNC(__pkvm_vcpu_put),
 };
 
 static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index d46a02e24e4a..496d186efb03 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -23,6 +23,12 @@ unsigned int kvm_arm_vmid_bits;
 
 unsigned int kvm_host_sve_max_vl;
 
+/*
+ * The currently loaded hyp vCPU for each physical CPU. Used only when
+ * protected KVM is enabled, but for both protected and non-protected VMs.
+ */
+static DEFINE_PER_CPU(struct pkvm_hyp_vcpu *, loaded_hyp_vcpu);
+
 /*
  * Set trap register values based on features in ID_AA64PFR0.
  */
@@ -306,15 +312,30 @@ struct pkvm_hyp_vcpu *pkvm_load_hyp_vcpu(pkvm_handle_t handle,
 	struct pkvm_hyp_vcpu *hyp_vcpu = NULL;
 	struct pkvm_hyp_vm *hyp_vm;
 
+	/* Cannot load a new vcpu without putting the old one first. */
+	if (__this_cpu_read(loaded_hyp_vcpu))
+		return NULL;
+
 	hyp_spin_lock(&vm_table_lock);
 	hyp_vm = get_vm_by_handle(handle);
 	if (!hyp_vm || hyp_vm->nr_vcpus <= vcpu_idx)
 		goto unlock;
 
 	hyp_vcpu = hyp_vm->vcpus[vcpu_idx];
+
+	/* Ensure vcpu isn't loaded on more than one cpu simultaneously. */
+	if (unlikely(hyp_vcpu->loaded_hyp_vcpu)) {
+		hyp_vcpu = NULL;
+		goto unlock;
+	}
+
+	hyp_vcpu->loaded_hyp_vcpu = this_cpu_ptr(&loaded_hyp_vcpu);
 	hyp_page_ref_inc(hyp_virt_to_page(hyp_vm));
 unlock:
 	hyp_spin_unlock(&vm_table_lock);
+
+	if (hyp_vcpu)
+		__this_cpu_write(loaded_hyp_vcpu, hyp_vcpu);
 	return hyp_vcpu;
 }
 
@@ -323,10 +344,18 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	struct pkvm_hyp_vm *hyp_vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu);
 
 	hyp_spin_lock(&vm_table_lock);
+	hyp_vcpu->loaded_hyp_vcpu = NULL;
+	__this_cpu_write(loaded_hyp_vcpu, NULL);
 	hyp_page_ref_dec(hyp_virt_to_page(hyp_vm));
 	hyp_spin_unlock(&vm_table_lock);
 }
 
+struct pkvm_hyp_vcpu *pkvm_get_loaded_hyp_vcpu(void)
+{
+	return __this_cpu_read(loaded_hyp_vcpu);
+
+}
+
 struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle)
 {
 	struct pkvm_hyp_vm *hyp_vm;
diff --git a/arch/arm64/kvm/vgic/vgic-v3.c b/arch/arm64/kvm/vgic/vgic-v3.c
index f267bc2486a1..c2ef41fff079 100644
--- a/arch/arm64/kvm/vgic/vgic-v3.c
+++ b/arch/arm64/kvm/vgic/vgic-v3.c
@@ -734,7 +734,8 @@ void vgic_v3_load(struct kvm_vcpu *vcpu)
 {
 	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
 
-	kvm_call_hyp(__vgic_v3_restore_vmcr_aprs, cpu_if);
+	if (likely(!is_protected_kvm_enabled()))
+		kvm_call_hyp(__vgic_v3_restore_vmcr_aprs, cpu_if);
 
 	if (has_vhe())
 		__vgic_v3_activate_traps(cpu_if);
@@ -746,7 +747,8 @@ void vgic_v3_put(struct kvm_vcpu *vcpu)
 {
 	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
 
-	kvm_call_hyp(__vgic_v3_save_vmcr_aprs, cpu_if);
+	if (likely(!is_protected_kvm_enabled()))
+		kvm_call_hyp(__vgic_v3_save_vmcr_aprs, cpu_if);
 	WARN_ON(vgic_v4_put(vcpu));
 
 	if (has_vhe())
-- 
2.47.1.613.gc27f4b7a9f-goog

Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 3987 bytes --]

On Wed, Dec 18, 2024 at 07:40:50PM +0000, Quentin Perret wrote:
> From: Marc Zyngier <maz@kernel.org>
> 
> Rather than look-up the hyp vCPU on every run hypercall at EL2,
> introduce a per-CPU 'loaded_hyp_vcpu' tracking variable which is updated
> by a pair of load/put hypercalls called directly from
> kvm_arch_vcpu_{load,put}() when pKVM is enabled.

Current mainline crashes when running the arch_timer_edge_cases selftest
in pKVM mode on a LibreTech Le Potato board, with a bisection pointing
at this change.  The system dies like this:

# selftests: kvm: arch_timer_edge_cases
[  130.599140] kvm [4518]: nVHE hyp panic at: [<ffff800081102b58>] __kvm_nvhe___vgic_v3_restore_vmcr_aprs+0x8/0x84!
[  130.603685] kvm [4518]: Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE
[  130.611962] kvm [4518]: Hyp Offset: 0xfffeca95ed000000
[  130.617053] Kernel panic - not syncing: HYP panic:

Full log:

   https://lava.sirena.org.uk/scheduler/job/1092083

Bisection log:

git bisect start
# status: waiting for both good and bad commits
# bad: [2014c95afecee3e76ca4a56956a936e23283f05b] Linux 6.14-rc1
git bisect bad 2014c95afecee3e76ca4a56956a936e23283f05b
# status: waiting for good commit(s), bad commit known
# good: [ffd294d346d185b70e28b1a28abe367bbfe53c04] Linux 6.13
git bisect good ffd294d346d185b70e28b1a28abe367bbfe53c04
# good: [6250ebe666e425e173df5e11e8a612d57921f48d] i2c: Fix core-managed per-client debugfs handling
git bisect good 6250ebe666e425e173df5e11e8a612d57921f48d
# good: [647d69605c70368d54fc012fce8a43e8e5955b04] Merge tag 'pci-v6.14-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci
git bisect good 647d69605c70368d54fc012fce8a43e8e5955b04
# good: [13845bdc869f136f92ad3d40ea09b867bb4ce467] Merge tag 'char-misc-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
git bisect good 13845bdc869f136f92ad3d40ea09b867bb4ce467
# bad: [9f10e7fb6a06bce4f81de5fd0f2f0390f99e89e4] Merge tag 'phy-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/phy/linux-phy
git bisect bad 9f10e7fb6a06bce4f81de5fd0f2f0390f99e89e4
# bad: [58f504efcda54a9079a38203acc088c3354aaa60] Merge tag 'tty-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
git bisect bad 58f504efcda54a9079a38203acc088c3354aaa60
# good: [a37eea94f775132866ecdd466fd88027d7125515] Merge tag 'sparc-for-6.14-tag1' of git://git.kernel.org/pub/scm/linux/kernel/git/alarsson/linux-sparc
git bisect good a37eea94f775132866ecdd466fd88027d7125515
# bad: [5e68d2eeac70978a06406c5b156815ceb00437f9] Merge branch kvm-arm64/pkvm-memshare-declutter into kvmarm-master/next
git bisect bad 5e68d2eeac70978a06406c5b156815ceb00437f9
# bad: [d0670128d42fa170bf8ba878cd23504c5c5cccc7] Merge branch kvm-arm64/pkvm-np-guest into kvmarm-master/next
git bisect bad d0670128d42fa170bf8ba878cd23504c5c5cccc7
# good: [c4a6ed85455979ef3fbadc2f1bdf18734b0ecea6] KVM: arm64: Promote guest ownership for DBGxVR/DBGxCR reads
git bisect good c4a6ed85455979ef3fbadc2f1bdf18734b0ecea6
# bad: [d0bd3e6570aee42766e7bd884734ae078667ea1e] KVM: arm64: Introduce __pkvm_host_share_guest()
git bisect bad d0bd3e6570aee42766e7bd884734ae078667ea1e
# good: [5398ddc5c90bd418b90d859e9267aa39399021af] KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung
git bisect good 5398ddc5c90bd418b90d859e9267aa39399021af
# good: [c77e5181fed54b25d489eb7d2ccb5c1c72a1063c] KVM: arm64: Make kvm_pgtable_stage2_init() a static inline function
git bisect good c77e5181fed54b25d489eb7d2ccb5c1c72a1063c
# bad: [f7d03fcbf1f482069e9afac55b17de3bd323b8f6] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()
git bisect bad f7d03fcbf1f482069e9afac55b17de3bd323b8f6
# good: [99996d575ee69d4327bad98a0148729b73dde23a] KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers
git bisect good 99996d575ee69d4327bad98a0148729b73dde23a
# first bad commit: [f7d03fcbf1f482069e9afac55b17de3bd323b8f6] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[Oliver Upton]

On Mon, Feb 03, 2025 at 07:50:44PM +0000, Mark Brown wrote:
> On Wed, Dec 18, 2024 at 07:40:50PM +0000, Quentin Perret wrote:
> > From: Marc Zyngier <maz@kernel.org>
> > 
> > Rather than look-up the hyp vCPU on every run hypercall at EL2,
> > introduce a per-CPU 'loaded_hyp_vcpu' tracking variable which is updated
> > by a pair of load/put hypercalls called directly from
> > kvm_arch_vcpu_{load,put}() when pKVM is enabled.
> 
> Current mainline crashes when running the arch_timer_edge_cases selftest
> in pKVM mode on a LibreTech Le Potato board, with a bisection pointing
> at this change.  The system dies like this:
> 
> # selftests: kvm: arch_timer_edge_cases
> [  130.599140] kvm [4518]: nVHE hyp panic at: [<ffff800081102b58>] __kvm_nvhe___vgic_v3_restore_vmcr_aprs+0x8/0x84!
> [  130.603685] kvm [4518]: Cannot dump pKVM nVHE stacktrace: !CONFIG_PROTECTED_NVHE_STACKTRACE
> [  130.611962] kvm [4518]: Hyp Offset: 0xfffeca95ed000000
> [  130.617053] Kernel panic - not syncing: HYP panic:

Thanks, fix posted here [*], although as a consequence this machine will
stop running KVM in protected mode (which was never meant to work in the
first place).

[*]: https://lore.kernel.org/kvmarm/20250203231543.233511-1-oliver.upton@linux.dev/

-- 
Thanks,
Oliver

Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 794 bytes --]

On Mon, Feb 03, 2025 at 03:19:03PM -0800, Oliver Upton wrote:
> On Mon, Feb 03, 2025 at 07:50:44PM +0000, Mark Brown wrote:

> > Current mainline crashes when running the arch_timer_edge_cases selftest
> > in pKVM mode on a LibreTech Le Potato board, with a bisection pointing
> > at this change.  The system dies like this:
> > 
> > # selftests: kvm: arch_timer_edge_cases
> > [  130.599140] kvm [4518]: nVHE hyp panic at: [<ffff800081102b58>] __kvm_nvhe___vgic_v3_restore_vmcr_aprs+0x8/0x84!

> Thanks, fix posted here [*], although as a consequence this machine will
> stop running KVM in protected mode (which was never meant to work in the
> first place).

Yeah, I wasn't clear if this was something that was intended to work or
not - it's all in a constant state of flux.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH v4 09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()

[Quentin Perret]

On Tuesday 04 Feb 2025 at 14:32:19 (+0000), Mark Brown wrote:
> On Mon, Feb 03, 2025 at 03:19:03PM -0800, Oliver Upton wrote:
> > On Mon, Feb 03, 2025 at 07:50:44PM +0000, Mark Brown wrote:
> 
> > > Current mainline crashes when running the arch_timer_edge_cases selftest
> > > in pKVM mode on a LibreTech Le Potato board, with a bisection pointing
> > > at this change.  The system dies like this:
> > > 
> > > # selftests: kvm: arch_timer_edge_cases
> > > [  130.599140] kvm [4518]: nVHE hyp panic at: [<ffff800081102b58>] __kvm_nvhe___vgic_v3_restore_vmcr_aprs+0x8/0x84!
> 
> > Thanks, fix posted here [*], although as a consequence this machine will
> > stop running KVM in protected mode (which was never meant to work in the
> > first place).
> 
> Yeah, I wasn't clear if this was something that was intended to work or
> not - it's all in a constant state of flux.

FWIW a770ee80e662 ("KVM: arm64: pkvm: Disable GICv2 support") did try to
explicitly disable things, but was clearly incomplete...

Thanks guys for the report and the quick fix!
Quentin

[PATCH v4 10/18] KVM: arm64: Introduce __pkvm_host_share_guest()

[Quentin Perret]

In preparation for handling guest stage-2 mappings at EL2, introduce a
new pKVM hypercall allowing to share pages with non-protected guests.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/include/asm/kvm_host.h             |  3 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  2 +
 arch/arm64/kvm/hyp/include/nvhe/memory.h      |  4 +-
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 34 +++++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 72 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/pkvm.c                |  8 +++
 7 files changed, 123 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 89c0fac69551..449337f5b2a3 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -65,6 +65,7 @@ enum __kvm_host_smccc_func {
 	/* Hypercalls available after pKVM finalisation */
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index e18e9244d17a..1246f1d01dbf 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -771,6 +771,9 @@ struct kvm_vcpu_arch {
 	/* Cache some mmu pages needed inside spinlock regions */
 	struct kvm_mmu_memory_cache mmu_page_cache;
 
+	/* Pages to top-up the pKVM/EL2 guest pool */
+	struct kvm_hyp_memcache pkvm_memcache;
+
 	/* Virtual SError ESR to restore when HCR_EL2.VSE is set */
 	u64 vsesr_el2;
 
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 25038ac705d8..15b8956051b6 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -39,6 +39,8 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
 int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
 int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);
 int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
+int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
+			    enum kvm_pgtable_prot prot);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/include/nvhe/memory.h b/arch/arm64/kvm/hyp/include/nvhe/memory.h
index 2a5eabf4b753..34233d586060 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/memory.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/memory.h
@@ -46,6 +46,8 @@ struct hyp_page {
 
 	/* Host (non-meta) state. Guarded by the host stage-2 lock. */
 	enum pkvm_page_state host_state : 8;
+
+	u32 host_share_guest_count;
 };
 
 extern u64 __hyp_vmemmap;
@@ -68,7 +70,7 @@ static inline phys_addr_t hyp_virt_to_phys(void *addr)
 
 static inline struct hyp_page *hyp_phys_to_page(phys_addr_t phys)
 {
-	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u32));
+	BUILD_BUG_ON(sizeof(struct hyp_page) != sizeof(u64));
 	return &hyp_vmemmap[hyp_phys_to_pfn(phys)];
 }
 
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 95d78db315b3..d659462fbf5d 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -211,6 +211,39 @@ static void handle___kvm_vcpu_run(struct kvm_cpu_context *host_ctxt)
 	cpu_reg(host_ctxt, 1) =  ret;
 }
 
+static int pkvm_refill_memcache(struct pkvm_hyp_vcpu *hyp_vcpu)
+{
+	struct kvm_vcpu *host_vcpu = hyp_vcpu->host_vcpu;
+
+	return refill_memcache(&hyp_vcpu->vcpu.arch.pkvm_memcache,
+			       host_vcpu->arch.pkvm_memcache.nr_pages,
+			       &host_vcpu->arch.pkvm_memcache);
+}
+
+static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u64, pfn, host_ctxt, 1);
+	DECLARE_REG(u64, gfn, host_ctxt, 2);
+	DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 3);
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();
+	if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu))
+		goto out;
+
+	ret = pkvm_refill_memcache(hyp_vcpu);
+	if (ret)
+		goto out;
+
+	ret = __pkvm_host_share_guest(pfn, gfn, hyp_vcpu, prot);
+out:
+	cpu_reg(host_ctxt, 1) =  ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -420,6 +453,7 @@ static const hcall_t host_hcall[] = {
 
 	HANDLE_FUNC(__pkvm_host_share_hyp),
 	HANDLE_FUNC(__pkvm_host_unshare_hyp),
+	HANDLE_FUNC(__pkvm_host_share_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 12bb5445fe47..fb9592e721cf 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -867,6 +867,27 @@ static int hyp_complete_donation(u64 addr,
 	return pkvm_create_mappings_locked(start, end, prot);
 }
 
+static enum pkvm_page_state guest_get_page_state(kvm_pte_t pte, u64 addr)
+{
+	if (!kvm_pte_valid(pte))
+		return PKVM_NOPAGE;
+
+	return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
+}
+
+static int __guest_check_page_state_range(struct pkvm_hyp_vcpu *vcpu, u64 addr,
+					  u64 size, enum pkvm_page_state state)
+{
+	struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
+	struct check_walk_data d = {
+		.desired	= state,
+		.get_page_state	= guest_get_page_state,
+	};
+
+	hyp_assert_lock_held(&vm->lock);
+	return check_page_state_range(&vm->pgt, addr, size, &d);
+}
+
 static int check_share(struct pkvm_mem_share *share)
 {
 	const struct pkvm_mem_transition *tx = &share->tx;
@@ -1349,3 +1370,54 @@ int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages)
 
 	return ret;
 }
+
+int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
+			    enum kvm_pgtable_prot prot)
+{
+	struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
+	u64 phys = hyp_pfn_to_phys(pfn);
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	struct hyp_page *page;
+	int ret;
+
+	if (prot & ~KVM_PGTABLE_PROT_RWX)
+		return -EINVAL;
+
+	ret = check_range_allowed_memory(phys, phys + PAGE_SIZE);
+	if (ret)
+		return ret;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __guest_check_page_state_range(vcpu, ipa, PAGE_SIZE, PKVM_NOPAGE);
+	if (ret)
+		goto unlock;
+
+	page = hyp_phys_to_page(phys);
+	switch (page->host_state) {
+	case PKVM_PAGE_OWNED:
+		WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_SHARED_OWNED));
+		break;
+	case PKVM_PAGE_SHARED_OWNED:
+		if (page->host_share_guest_count)
+			break;
+		/* Only host to np-guest multi-sharing is tolerated */
+		WARN_ON(1);
+		fallthrough;
+	default:
+		ret = -EPERM;
+		goto unlock;
+	}
+
+	WARN_ON(kvm_pgtable_stage2_map(&vm->pgt, ipa, PAGE_SIZE, phys,
+				       pkvm_mkstate(prot, PKVM_PAGE_SHARED_BORROWED),
+				       &vcpu->vcpu.arch.pkvm_memcache, 0));
+	page->host_share_guest_count++;
+
+unlock:
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 496d186efb03..0109c36566c8 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -795,6 +795,14 @@ int __pkvm_teardown_vm(pkvm_handle_t handle)
 	/* Push the metadata pages to the teardown memcache */
 	for (idx = 0; idx < hyp_vm->nr_vcpus; ++idx) {
 		struct pkvm_hyp_vcpu *hyp_vcpu = hyp_vm->vcpus[idx];
+		struct kvm_hyp_memcache *vcpu_mc = &hyp_vcpu->vcpu.arch.pkvm_memcache;
+
+		while (vcpu_mc->nr_pages) {
+			void *addr = pop_hyp_memcache(vcpu_mc, hyp_phys_to_virt);
+
+			push_hyp_memcache(mc, addr, hyp_virt_to_phys);
+			unmap_donated_memory_noclear(addr, PAGE_SIZE);
+		}
 
 		teardown_donated_memory(mc, hyp_vcpu, sizeof(*hyp_vcpu));
 	}
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 11/18] KVM: arm64: Introduce __pkvm_host_unshare_guest()

[Quentin Perret]

In preparation for letting the host unmap pages from non-protected
guests, introduce a new hypercall implementing the host-unshare-guest
transition.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 +
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h        |  6 ++
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 21 ++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 67 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/pkvm.c                | 12 ++++
 6 files changed, 108 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 449337f5b2a3..0b6c4d325134 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -66,6 +66,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_hyp,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 15b8956051b6..e6d080b71779 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -41,6 +41,7 @@ int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);
 int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
 int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
 			    enum kvm_pgtable_prot prot);
+int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index be52c5b15e21..0cc2a429f1fb 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -64,6 +64,11 @@ static inline bool pkvm_hyp_vcpu_is_protected(struct pkvm_hyp_vcpu *hyp_vcpu)
 	return vcpu_is_protected(&hyp_vcpu->vcpu);
 }
 
+static inline bool pkvm_hyp_vm_is_protected(struct pkvm_hyp_vm *hyp_vm)
+{
+	return kvm_vm_is_protected(&hyp_vm->kvm);
+}
+
 void pkvm_hyp_vm_table_init(void *tbl);
 
 int __pkvm_init_vm(struct kvm *host_kvm, unsigned long vm_hva,
@@ -78,6 +83,7 @@ void pkvm_put_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu);
 struct pkvm_hyp_vcpu *pkvm_get_loaded_hyp_vcpu(void);
 
 struct pkvm_hyp_vm *get_pkvm_hyp_vm(pkvm_handle_t handle);
+struct pkvm_hyp_vm *get_np_pkvm_hyp_vm(pkvm_handle_t handle);
 void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm);
 
 #endif /* __ARM64_KVM_NVHE_PKVM_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index d659462fbf5d..3c3a27c985a2 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -244,6 +244,26 @@ static void handle___pkvm_host_share_guest(struct kvm_cpu_context *host_ctxt)
 	cpu_reg(host_ctxt, 1) =  ret;
 }
 
+static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	DECLARE_REG(u64, gfn, host_ctxt, 2);
+	struct pkvm_hyp_vm *hyp_vm;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vm = get_np_pkvm_hyp_vm(handle);
+	if (!hyp_vm)
+		goto out;
+
+	ret = __pkvm_host_unshare_guest(gfn, hyp_vm);
+	put_pkvm_hyp_vm(hyp_vm);
+out:
+	cpu_reg(host_ctxt, 1) =  ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -454,6 +474,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_host_share_hyp),
 	HANDLE_FUNC(__pkvm_host_unshare_hyp),
 	HANDLE_FUNC(__pkvm_host_share_guest),
+	HANDLE_FUNC(__pkvm_host_unshare_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index fb9592e721cf..30243b7922f1 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -1421,3 +1421,70 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
 
 	return ret;
 }
+
+static int __check_host_shared_guest(struct pkvm_hyp_vm *vm, u64 *__phys, u64 ipa)
+{
+	enum pkvm_page_state state;
+	struct hyp_page *page;
+	kvm_pte_t pte;
+	u64 phys;
+	s8 level;
+	int ret;
+
+	ret = kvm_pgtable_get_leaf(&vm->pgt, ipa, &pte, &level);
+	if (ret)
+		return ret;
+	if (level != KVM_PGTABLE_LAST_LEVEL)
+		return -E2BIG;
+	if (!kvm_pte_valid(pte))
+		return -ENOENT;
+
+	state = guest_get_page_state(pte, ipa);
+	if (state != PKVM_PAGE_SHARED_BORROWED)
+		return -EPERM;
+
+	phys = kvm_pte_to_phys(pte);
+	ret = check_range_allowed_memory(phys, phys + PAGE_SIZE);
+	if (WARN_ON(ret))
+		return ret;
+
+	page = hyp_phys_to_page(phys);
+	if (page->host_state != PKVM_PAGE_SHARED_OWNED)
+		return -EPERM;
+	if (WARN_ON(!page->host_share_guest_count))
+		return -EINVAL;
+
+	*__phys = phys;
+
+	return 0;
+}
+
+int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *vm)
+{
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	struct hyp_page *page;
+	u64 phys;
+	int ret;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __check_host_shared_guest(vm, &phys, ipa);
+	if (ret)
+		goto unlock;
+
+	ret = kvm_pgtable_stage2_unmap(&vm->pgt, ipa, PAGE_SIZE);
+	if (ret)
+		goto unlock;
+
+	page = hyp_phys_to_page(phys);
+	page->host_share_guest_count--;
+	if (!page->host_share_guest_count)
+		WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_OWNED));
+
+unlock:
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 0109c36566c8..2c618f2f2769 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -376,6 +376,18 @@ void put_pkvm_hyp_vm(struct pkvm_hyp_vm *hyp_vm)
 	hyp_spin_unlock(&vm_table_lock);
 }
 
+struct pkvm_hyp_vm *get_np_pkvm_hyp_vm(pkvm_handle_t handle)
+{
+	struct pkvm_hyp_vm *hyp_vm = get_pkvm_hyp_vm(handle);
+
+	if (hyp_vm && pkvm_hyp_vm_is_protected(hyp_vm)) {
+		put_pkvm_hyp_vm(hyp_vm);
+		hyp_vm = NULL;
+	}
+
+	return hyp_vm;
+}
+
 static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struct kvm *host_kvm)
 {
 	struct kvm *kvm = &hyp_vm->kvm;
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 12/18] KVM: arm64: Introduce __pkvm_host_relax_guest_perms()

[Quentin Perret]

Introduce a new hypercall allowing the host to relax the stage-2
permissions of mappings in a non-protected guest page-table. It will be
used later once we start allowing RO memslots and dirty logging.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 20 ++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 23 +++++++++++++++++++
 4 files changed, 45 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 0b6c4d325134..66ee8542dcc9 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -67,6 +67,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_hyp,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index e6d080b71779..181aec2d5bc1 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -42,6 +42,7 @@ int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
 int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
 			    enum kvm_pgtable_prot prot);
 int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
+int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 3c3a27c985a2..287e4ee93ef2 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -264,6 +264,25 @@ static void handle___pkvm_host_unshare_guest(struct kvm_cpu_context *host_ctxt)
 	cpu_reg(host_ctxt, 1) =  ret;
 }
 
+static void handle___pkvm_host_relax_perms_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u64, gfn, host_ctxt, 1);
+	DECLARE_REG(enum kvm_pgtable_prot, prot, host_ctxt, 2);
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();
+	if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu))
+		goto out;
+
+	ret = __pkvm_host_relax_perms_guest(gfn, hyp_vcpu, prot);
+out:
+	cpu_reg(host_ctxt, 1) = ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -475,6 +494,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_host_unshare_hyp),
 	HANDLE_FUNC(__pkvm_host_share_guest),
 	HANDLE_FUNC(__pkvm_host_unshare_guest),
+	HANDLE_FUNC(__pkvm_host_relax_perms_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 30243b7922f1..aa8e0408aebb 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -1488,3 +1488,26 @@ int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *vm)
 
 	return ret;
 }
+
+int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot)
+{
+	struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	u64 phys;
+	int ret;
+
+	if (prot & ~KVM_PGTABLE_PROT_RWX)
+		return -EINVAL;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __check_host_shared_guest(vm, &phys, ipa);
+	if (!ret)
+		ret = kvm_pgtable_stage2_relax_perms(&vm->pgt, ipa, prot, 0);
+
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 13/18] KVM: arm64: Introduce __pkvm_host_wrprotect_guest()

[Quentin Perret]

Introduce a new hypercall to remove the write permission from a
non-protected guest stage-2 mapping. This will be used for e.g. enabling
dirty logging.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 21 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 19 +++++++++++++++++
 4 files changed, 42 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 66ee8542dcc9..8663a588cf34 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -68,6 +68,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_share_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 181aec2d5bc1..0bbfb0e1734c 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -43,6 +43,7 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
 			    enum kvm_pgtable_prot prot);
 int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);
+int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 287e4ee93ef2..98d317735107 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -283,6 +283,26 @@ static void handle___pkvm_host_relax_perms_guest(struct kvm_cpu_context *host_ct
 	cpu_reg(host_ctxt, 1) = ret;
 }
 
+static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	DECLARE_REG(u64, gfn, host_ctxt, 2);
+	struct pkvm_hyp_vm *hyp_vm;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vm = get_np_pkvm_hyp_vm(handle);
+	if (!hyp_vm)
+		goto out;
+
+	ret = __pkvm_host_wrprotect_guest(gfn, hyp_vm);
+	put_pkvm_hyp_vm(hyp_vm);
+out:
+	cpu_reg(host_ctxt, 1) = ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -495,6 +515,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_host_share_guest),
 	HANDLE_FUNC(__pkvm_host_unshare_guest),
 	HANDLE_FUNC(__pkvm_host_relax_perms_guest),
+	HANDLE_FUNC(__pkvm_host_wrprotect_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index aa8e0408aebb..94e4251b5077 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -1511,3 +1511,22 @@ int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_
 
 	return ret;
 }
+
+int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *vm)
+{
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	u64 phys;
+	int ret;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __check_host_shared_guest(vm, &phys, ipa);
+	if (!ret)
+		ret = kvm_pgtable_stage2_wrprotect(&vm->pgt, ipa, PAGE_SIZE);
+
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 14/18] KVM: arm64: Introduce __pkvm_host_test_clear_young_guest()

[Quentin Perret]

Plumb the kvm_stage2_test_clear_young() callback into pKVM for
non-protected guest. It will be later be called from MMU notifiers.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 22 +++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 19 ++++++++++++++++
 4 files changed, 43 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 8663a588cf34..4f97155d6323 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -69,6 +69,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_unshare_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_test_clear_young_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 0bbfb0e1734c..74bd6c72fff2 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -44,6 +44,7 @@ int __pkvm_host_share_guest(u64 pfn, u64 gfn, struct pkvm_hyp_vcpu *vcpu,
 int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);
 int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
+int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 98d317735107..616e172a9c48 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -303,6 +303,27 @@ static void handle___pkvm_host_wrprotect_guest(struct kvm_cpu_context *host_ctxt
 	cpu_reg(host_ctxt, 1) = ret;
 }
 
+static void handle___pkvm_host_test_clear_young_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	DECLARE_REG(u64, gfn, host_ctxt, 2);
+	DECLARE_REG(bool, mkold, host_ctxt, 3);
+	struct pkvm_hyp_vm *hyp_vm;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vm = get_np_pkvm_hyp_vm(handle);
+	if (!hyp_vm)
+		goto out;
+
+	ret = __pkvm_host_test_clear_young_guest(gfn, mkold, hyp_vm);
+	put_pkvm_hyp_vm(hyp_vm);
+out:
+	cpu_reg(host_ctxt, 1) = ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -516,6 +537,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_host_unshare_guest),
 	HANDLE_FUNC(__pkvm_host_relax_perms_guest),
 	HANDLE_FUNC(__pkvm_host_wrprotect_guest),
+	HANDLE_FUNC(__pkvm_host_test_clear_young_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 94e4251b5077..0e42c3baaf4b 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -1530,3 +1530,22 @@ int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *vm)
 
 	return ret;
 }
+
+int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm)
+{
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	u64 phys;
+	int ret;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __check_host_shared_guest(vm, &phys, ipa);
+	if (!ret)
+		ret = kvm_pgtable_stage2_test_clear_young(&vm->pgt, ipa, PAGE_SIZE, mkold);
+
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 15/18] KVM: arm64: Introduce __pkvm_host_mkyoung_guest()

[Quentin Perret]

Plumb the kvm_pgtable_stage2_mkyoung() callback into pKVM for
non-protected guests. It will be called later from the fault handling
path.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h              |  1 +
 arch/arm64/kvm/hyp/include/nvhe/mem_protect.h |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c            | 19 ++++++++++++++++++
 arch/arm64/kvm/hyp/nvhe/mem_protect.c         | 20 +++++++++++++++++++
 4 files changed, 41 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index 4f97155d6323..a3b07db2776c 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -70,6 +70,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_relax_perms_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_wrprotect_guest,
 	__KVM_HOST_SMCCC_FUNC___pkvm_host_test_clear_young_guest,
+	__KVM_HOST_SMCCC_FUNC___pkvm_host_mkyoung_guest,
 	__KVM_HOST_SMCCC_FUNC___kvm_adjust_pc,
 	__KVM_HOST_SMCCC_FUNC___kvm_vcpu_run,
 	__KVM_HOST_SMCCC_FUNC___kvm_flush_vm_context,
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 74bd6c72fff2..978f38c386ee 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -45,6 +45,7 @@ int __pkvm_host_unshare_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 int __pkvm_host_relax_perms_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu, enum kvm_pgtable_prot prot);
 int __pkvm_host_wrprotect_guest(u64 gfn, struct pkvm_hyp_vm *hyp_vm);
 int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *vm);
+int __pkvm_host_mkyoung_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu);
 
 bool addr_is_memory(phys_addr_t phys);
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 616e172a9c48..32c4627b5b5b 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -324,6 +324,24 @@ static void handle___pkvm_host_test_clear_young_guest(struct kvm_cpu_context *ho
 	cpu_reg(host_ctxt, 1) = ret;
 }
 
+static void handle___pkvm_host_mkyoung_guest(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(u64, gfn, host_ctxt, 1);
+	struct pkvm_hyp_vcpu *hyp_vcpu;
+	int ret = -EINVAL;
+
+	if (!is_protected_kvm_enabled())
+		goto out;
+
+	hyp_vcpu = pkvm_get_loaded_hyp_vcpu();
+	if (!hyp_vcpu || pkvm_hyp_vcpu_is_protected(hyp_vcpu))
+		goto out;
+
+	ret = __pkvm_host_mkyoung_guest(gfn, hyp_vcpu);
+out:
+	cpu_reg(host_ctxt, 1) =  ret;
+}
+
 static void handle___kvm_adjust_pc(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_vcpu *, vcpu, host_ctxt, 1);
@@ -538,6 +556,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_host_relax_perms_guest),
 	HANDLE_FUNC(__pkvm_host_wrprotect_guest),
 	HANDLE_FUNC(__pkvm_host_test_clear_young_guest),
+	HANDLE_FUNC(__pkvm_host_mkyoung_guest),
 	HANDLE_FUNC(__kvm_adjust_pc),
 	HANDLE_FUNC(__kvm_vcpu_run),
 	HANDLE_FUNC(__kvm_flush_vm_context),
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 0e42c3baaf4b..eae03509d371 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -1549,3 +1549,23 @@ int __pkvm_host_test_clear_young_guest(u64 gfn, bool mkold, struct pkvm_hyp_vm *
 
 	return ret;
 }
+
+int __pkvm_host_mkyoung_guest(u64 gfn, struct pkvm_hyp_vcpu *vcpu)
+{
+	struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(vcpu);
+	u64 ipa = hyp_pfn_to_phys(gfn);
+	u64 phys;
+	int ret;
+
+	host_lock_component();
+	guest_lock_component(vm);
+
+	ret = __check_host_shared_guest(vm, &phys, ipa);
+	if (!ret)
+		kvm_pgtable_stage2_mkyoung(&vm->pgt, ipa, 0);
+
+	guest_unlock_component(vm);
+	host_unlock_component();
+
+	return ret;
+}
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 16/18] KVM: arm64: Introduce __pkvm_tlb_flush_vmid()

[Quentin Perret]

Introduce a new hypercall to flush the TLBs of non-protected guests. The
host kernel will be responsible for issuing this hypercall after changing
stage-2 permissions using the __pkvm_host_relax_guest_perms() or
__pkvm_host_wrprotect_guest() paths. This is left under the host's
responsibility for performance reasons.

Note however that the TLB maintenance for all *unmap* operations still
remains entirely under the hypervisor's responsibility for security
reasons -- an unmapped page may be donated to another entity, so a stale
TLB entry could be used to leak private data.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_asm.h   |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-main.c | 17 +++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h
index a3b07db2776c..002088c6e297 100644
--- a/arch/arm64/include/asm/kvm_asm.h
+++ b/arch/arm64/include/asm/kvm_asm.h
@@ -87,6 +87,7 @@ enum __kvm_host_smccc_func {
 	__KVM_HOST_SMCCC_FUNC___pkvm_teardown_vm,
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_load,
 	__KVM_HOST_SMCCC_FUNC___pkvm_vcpu_put,
+	__KVM_HOST_SMCCC_FUNC___pkvm_tlb_flush_vmid,
 };
 
 #define DECLARE_KVM_VHE_SYM(sym)	extern char sym[]
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 32c4627b5b5b..130f5f23bcb5 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -389,6 +389,22 @@ static void handle___kvm_tlb_flush_vmid(struct kvm_cpu_context *host_ctxt)
 	__kvm_tlb_flush_vmid(kern_hyp_va(mmu));
 }
 
+static void handle___pkvm_tlb_flush_vmid(struct kvm_cpu_context *host_ctxt)
+{
+	DECLARE_REG(pkvm_handle_t, handle, host_ctxt, 1);
+	struct pkvm_hyp_vm *hyp_vm;
+
+	if (!is_protected_kvm_enabled())
+		return;
+
+	hyp_vm = get_np_pkvm_hyp_vm(handle);
+	if (!hyp_vm)
+		return;
+
+	__kvm_tlb_flush_vmid(&hyp_vm->kvm.arch.mmu);
+	put_pkvm_hyp_vm(hyp_vm);
+}
+
 static void handle___kvm_flush_cpu_context(struct kvm_cpu_context *host_ctxt)
 {
 	DECLARE_REG(struct kvm_s2_mmu *, mmu, host_ctxt, 1);
@@ -573,6 +589,7 @@ static const hcall_t host_hcall[] = {
 	HANDLE_FUNC(__pkvm_teardown_vm),
 	HANDLE_FUNC(__pkvm_vcpu_load),
 	HANDLE_FUNC(__pkvm_vcpu_put),
+	HANDLE_FUNC(__pkvm_tlb_flush_vmid),
 };
 
 static void handle_host_hcall(struct kvm_cpu_context *host_ctxt)
-- 
2.47.1.613.gc27f4b7a9f-goog

[PATCH v4 17/18] KVM: arm64: Introduce the EL1 pKVM MMU

[Quentin Perret]

Introduce a set of helper functions allowing to manipulate the pKVM
guest stage-2 page-tables from EL1 using pKVM's HVC interface.

Each helper has an exact one-to-one correspondance with the traditional
kvm_pgtable_stage2_*() functions from pgtable.c, with a strictly
matching prototype. This will ease plumbing later on in mmu.c.

These callbacks track the gfn->pfn mappings in a simple rb_tree indexed
by IPA in lieu of a page-table. This rb-tree is kept in sync with pKVM's
state and is protected by the mmu_lock like a traditional stage-2
page-table.

Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_host.h    |   1 +
 arch/arm64/include/asm/kvm_pgtable.h |  23 +--
 arch/arm64/include/asm/kvm_pkvm.h    |  26 ++++
 arch/arm64/kvm/pkvm.c                | 201 +++++++++++++++++++++++++++
 4 files changed, 242 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 1246f1d01dbf..f23f4ea9ec8b 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -85,6 +85,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
 struct kvm_hyp_memcache {
 	phys_addr_t head;
 	unsigned long nr_pages;
+	struct pkvm_mapping *mapping; /* only used from EL1 */
 };
 
 static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc,
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 04418b5e3004..6b9d274052c7 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -412,15 +412,20 @@ static inline bool kvm_pgtable_walk_lock_held(void)
  *			be used instead of block mappings.
  */
 struct kvm_pgtable {
-	u32					ia_bits;
-	s8					start_level;
-	kvm_pteref_t				pgd;
-	struct kvm_pgtable_mm_ops		*mm_ops;
-
-	/* Stage-2 only */
-	struct kvm_s2_mmu			*mmu;
-	enum kvm_pgtable_stage2_flags		flags;
-	kvm_pgtable_force_pte_cb_t		force_pte_cb;
+	union {
+		struct rb_root					pkvm_mappings;
+		struct {
+			u32					ia_bits;
+			s8					start_level;
+			kvm_pteref_t				pgd;
+			struct kvm_pgtable_mm_ops		*mm_ops;
+
+			/* Stage-2 only */
+			enum kvm_pgtable_stage2_flags		flags;
+			kvm_pgtable_force_pte_cb_t		force_pte_cb;
+		};
+	};
+	struct kvm_s2_mmu					*mmu;
 };
 
 /**
diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
index cd56acd9a842..65f988b6fe0d 100644
--- a/arch/arm64/include/asm/kvm_pkvm.h
+++ b/arch/arm64/include/asm/kvm_pkvm.h
@@ -137,4 +137,30 @@ static inline size_t pkvm_host_sve_state_size(void)
 			SVE_SIG_REGS_SIZE(sve_vq_from_vl(kvm_host_sve_max_vl)));
 }
 
+struct pkvm_mapping {
+	struct rb_node node;
+	u64 gfn;
+	u64 pfn;
+};
+
+int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
+			     struct kvm_pgtable_mm_ops *mm_ops);
+void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt);
+int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
+			    enum kvm_pgtable_prot prot, void *mc,
+			    enum kvm_pgtable_walk_flags flags);
+int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size);
+int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
+int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size);
+bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold);
+int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
+				    enum kvm_pgtable_walk_flags flags);
+void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
+				 enum kvm_pgtable_walk_flags flags);
+int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
+			      struct kvm_mmu_memory_cache *mc);
+void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level);
+kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
+					       enum kvm_pgtable_prot prot, void *mc,
+					       bool force_pte);
 #endif	/* __ARM64_KVM_PKVM_H__ */
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 85117ea8f351..930b677eb9b0 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -7,6 +7,7 @@
 #include <linux/init.h>
 #include <linux/kmemleak.h>
 #include <linux/kvm_host.h>
+#include <asm/kvm_mmu.h>
 #include <linux/memblock.h>
 #include <linux/mutex.h>
 #include <linux/sort.h>
@@ -268,3 +269,203 @@ static int __init finalize_pkvm(void)
 	return ret;
 }
 device_initcall_sync(finalize_pkvm);
+
+static int cmp_mappings(struct rb_node *node, const struct rb_node *parent)
+{
+	struct pkvm_mapping *a = rb_entry(node, struct pkvm_mapping, node);
+	struct pkvm_mapping *b = rb_entry(parent, struct pkvm_mapping, node);
+
+	if (a->gfn < b->gfn)
+		return -1;
+	if (a->gfn > b->gfn)
+		return 1;
+	return 0;
+}
+
+static struct rb_node *find_first_mapping_node(struct rb_root *root, u64 gfn)
+{
+	struct rb_node *node = root->rb_node, *prev = NULL;
+	struct pkvm_mapping *mapping;
+
+	while (node) {
+		mapping = rb_entry(node, struct pkvm_mapping, node);
+		if (mapping->gfn == gfn)
+			return node;
+		prev = node;
+		node = (gfn < mapping->gfn) ? node->rb_left : node->rb_right;
+	}
+
+	return prev;
+}
+
+/*
+ * __tmp is updated to rb_next(__tmp) *before* entering the body of the loop to allow freeing
+ * of __map inline.
+ */
+#define for_each_mapping_in_range_safe(__pgt, __start, __end, __map)				\
+	for (struct rb_node *__tmp = find_first_mapping_node(&(__pgt)->pkvm_mappings,		\
+							     ((__start) >> PAGE_SHIFT));	\
+	     __tmp && ({									\
+				__map = rb_entry(__tmp, struct pkvm_mapping, node);		\
+				__tmp = rb_next(__tmp);						\
+				true;								\
+		       });									\
+	    )											\
+		if (__map->gfn < ((__start) >> PAGE_SHIFT))					\
+			continue;								\
+		else if (__map->gfn >= ((__end) >> PAGE_SHIFT))					\
+			break;									\
+		else
+
+int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
+			     struct kvm_pgtable_mm_ops *mm_ops)
+{
+	pgt->pkvm_mappings	= RB_ROOT;
+	pgt->mmu		= mmu;
+
+	return 0;
+}
+
+void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	struct rb_node *node;
+
+	if (!handle)
+		return;
+
+	node = rb_first(&pgt->pkvm_mappings);
+	while (node) {
+		mapping = rb_entry(node, struct pkvm_mapping, node);
+		kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
+		node = rb_next(node);
+		rb_erase(&mapping->node, &pgt->pkvm_mappings);
+		kfree(mapping);
+	}
+}
+
+int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
+			   u64 phys, enum kvm_pgtable_prot prot,
+			   void *mc, enum kvm_pgtable_walk_flags flags)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	struct pkvm_mapping *mapping = NULL;
+	struct kvm_hyp_memcache *cache = mc;
+	u64 gfn = addr >> PAGE_SHIFT;
+	u64 pfn = phys >> PAGE_SHIFT;
+	int ret;
+
+	if (size != PAGE_SIZE)
+		return -EINVAL;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, prot);
+	if (ret) {
+		/* Is the gfn already mapped due to a racing vCPU? */
+		if (ret == -EPERM)
+			return -EAGAIN;
+	}
+
+	swap(mapping, cache->mapping);
+	mapping->gfn = gfn;
+	mapping->pfn = pfn;
+	WARN_ON(rb_find_add(&mapping->node, &pgt->pkvm_mappings, cmp_mappings));
+
+	return ret;
+}
+
+int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	int ret = 0;
+
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
+		ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
+		if (WARN_ON(ret))
+			break;
+		rb_erase(&mapping->node, &pgt->pkvm_mappings);
+		kfree(mapping);
+	}
+
+	return ret;
+}
+
+int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	int ret = 0;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
+		ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn);
+		if (WARN_ON(ret))
+			break;
+	}
+
+	return ret;
+}
+
+int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	struct pkvm_mapping *mapping;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
+		__clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn), PAGE_SIZE);
+
+	return 0;
+}
+
+bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold)
+{
+	struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
+	pkvm_handle_t handle = kvm->arch.pkvm.handle;
+	struct pkvm_mapping *mapping;
+	bool young = false;
+
+	lockdep_assert_held(&kvm->mmu_lock);
+	for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
+		young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn,
+					   mkold);
+
+	return young;
+}
+
+int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
+				    enum kvm_pgtable_walk_flags flags)
+{
+	return kvm_call_hyp_nvhe(__pkvm_host_relax_perms_guest, addr >> PAGE_SHIFT, prot);
+}
+
+void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
+				 enum kvm_pgtable_walk_flags flags)
+{
+	WARN_ON(kvm_call_hyp_nvhe(__pkvm_host_mkyoung_guest, addr >> PAGE_SHIFT));
+}
+
+void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
+{
+	WARN_ON_ONCE(1);
+}
+
+kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
+					enum kvm_pgtable_prot prot, void *mc, bool force_pte)
+{
+	WARN_ON_ONCE(1);
+	return NULL;
+}
+
+int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
+			      struct kvm_mmu_memory_cache *mc)
+{
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
-- 
2.47.1.613.gc27f4b7a9f-goog

Re: [PATCH v4 17/18] KVM: arm64: Introduce the EL1 pKVM MMU

[Fuad Tabba]

Hi Quentin

On Wed, 18 Dec 2024 at 19:41, Quentin Perret <qperret@google.com> wrote:
>
> Introduce a set of helper functions allowing to manipulate the pKVM
> guest stage-2 page-tables from EL1 using pKVM's HVC interface.
>
> Each helper has an exact one-to-one correspondance with the traditional
> kvm_pgtable_stage2_*() functions from pgtable.c, with a strictly
> matching prototype. This will ease plumbing later on in mmu.c.
>
> These callbacks track the gfn->pfn mappings in a simple rb_tree indexed
> by IPA in lieu of a page-table. This rb-tree is kept in sync with pKVM's
> state and is protected by the mmu_lock like a traditional stage-2
> page-table.
>
> Signed-off-by: Quentin Perret <qperret@google.com>

Minor nits (feel free to ignore). Apart from that, and despite that
for_each_mapping_in_range_safe macro:

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>


> ---
>  arch/arm64/include/asm/kvm_host.h    |   1 +
>  arch/arm64/include/asm/kvm_pgtable.h |  23 +--
>  arch/arm64/include/asm/kvm_pkvm.h    |  26 ++++
>  arch/arm64/kvm/pkvm.c                | 201 +++++++++++++++++++++++++++
>  4 files changed, 242 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 1246f1d01dbf..f23f4ea9ec8b 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -85,6 +85,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
>  struct kvm_hyp_memcache {
>         phys_addr_t head;
>         unsigned long nr_pages;
> +       struct pkvm_mapping *mapping; /* only used from EL1 */
>  };
>
>  static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc,
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index 04418b5e3004..6b9d274052c7 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -412,15 +412,20 @@ static inline bool kvm_pgtable_walk_lock_held(void)
>   *                     be used instead of block mappings.
>   */
>  struct kvm_pgtable {
> -       u32                                     ia_bits;
> -       s8                                      start_level;
> -       kvm_pteref_t                            pgd;
> -       struct kvm_pgtable_mm_ops               *mm_ops;
> -
> -       /* Stage-2 only */
> -       struct kvm_s2_mmu                       *mmu;
> -       enum kvm_pgtable_stage2_flags           flags;
> -       kvm_pgtable_force_pte_cb_t              force_pte_cb;
> +       union {
> +               struct rb_root                                  pkvm_mappings;
> +               struct {
> +                       u32                                     ia_bits;
> +                       s8                                      start_level;
> +                       kvm_pteref_t                            pgd;
> +                       struct kvm_pgtable_mm_ops               *mm_ops;
> +
> +                       /* Stage-2 only */
> +                       enum kvm_pgtable_stage2_flags           flags;
> +                       kvm_pgtable_force_pte_cb_t              force_pte_cb;
> +               };
> +       };
> +       struct kvm_s2_mmu                                       *mmu;
>  };
>
>  /**
> diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
> index cd56acd9a842..65f988b6fe0d 100644
> --- a/arch/arm64/include/asm/kvm_pkvm.h
> +++ b/arch/arm64/include/asm/kvm_pkvm.h
> @@ -137,4 +137,30 @@ static inline size_t pkvm_host_sve_state_size(void)
>                         SVE_SIG_REGS_SIZE(sve_vq_from_vl(kvm_host_sve_max_vl)));
>  }
>
> +struct pkvm_mapping {
> +       struct rb_node node;
> +       u64 gfn;
> +       u64 pfn;
> +};
> +
> +int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
> +                            struct kvm_pgtable_mm_ops *mm_ops);
> +void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt);
> +int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
> +                           enum kvm_pgtable_prot prot, void *mc,
> +                           enum kvm_pgtable_walk_flags flags);
> +int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size);
> +int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
> +int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size);
> +bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold);
> +int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
> +                                   enum kvm_pgtable_walk_flags flags);
> +void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
> +                                enum kvm_pgtable_walk_flags flags);
> +int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
> +                             struct kvm_mmu_memory_cache *mc);
> +void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level);
> +kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
> +                                              enum kvm_pgtable_prot prot, void *mc,
> +                                              bool force_pte);
>  #endif /* __ARM64_KVM_PKVM_H__ */
> diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
> index 85117ea8f351..930b677eb9b0 100644
> --- a/arch/arm64/kvm/pkvm.c
> +++ b/arch/arm64/kvm/pkvm.c
> @@ -7,6 +7,7 @@
>  #include <linux/init.h>
>  #include <linux/kmemleak.h>
>  #include <linux/kvm_host.h>
> +#include <asm/kvm_mmu.h>
>  #include <linux/memblock.h>
>  #include <linux/mutex.h>
>  #include <linux/sort.h>
> @@ -268,3 +269,203 @@ static int __init finalize_pkvm(void)
>         return ret;
>  }
>  device_initcall_sync(finalize_pkvm);
> +
> +static int cmp_mappings(struct rb_node *node, const struct rb_node *parent)
> +{
> +       struct pkvm_mapping *a = rb_entry(node, struct pkvm_mapping, node);
> +       struct pkvm_mapping *b = rb_entry(parent, struct pkvm_mapping, node);
> +
> +       if (a->gfn < b->gfn)
> +               return -1;
> +       if (a->gfn > b->gfn)
> +               return 1;
> +       return 0;
> +}
> +
> +static struct rb_node *find_first_mapping_node(struct rb_root *root, u64 gfn)
> +{
> +       struct rb_node *node = root->rb_node, *prev = NULL;
> +       struct pkvm_mapping *mapping;
> +
> +       while (node) {
> +               mapping = rb_entry(node, struct pkvm_mapping, node);
> +               if (mapping->gfn == gfn)
> +                       return node;
> +               prev = node;
> +               node = (gfn < mapping->gfn) ? node->rb_left : node->rb_right;
> +       }
> +
> +       return prev;
> +}
> +
> +/*
> + * __tmp is updated to rb_next(__tmp) *before* entering the body of the loop to allow freeing
> + * of __map inline.
> + */
> +#define for_each_mapping_in_range_safe(__pgt, __start, __end, __map)                           \
> +       for (struct rb_node *__tmp = find_first_mapping_node(&(__pgt)->pkvm_mappings,           \
> +                                                            ((__start) >> PAGE_SHIFT));        \
> +            __tmp && ({                                                                        \
> +                               __map = rb_entry(__tmp, struct pkvm_mapping, node);             \
> +                               __tmp = rb_next(__tmp);                                         \
> +                               true;                                                           \
> +                      });                                                                      \
> +           )                                                                                   \
> +               if (__map->gfn < ((__start) >> PAGE_SHIFT))                                     \
> +                       continue;                                                               \
> +               else if (__map->gfn >= ((__end) >> PAGE_SHIFT))                                 \
> +                       break;                                                                  \
> +               else
> +
> +int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
> +                            struct kvm_pgtable_mm_ops *mm_ops)
> +{
> +       pgt->pkvm_mappings      = RB_ROOT;
> +       pgt->mmu                = mmu;
> +
> +       return 0;
> +}
> +
> +void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> +       struct pkvm_mapping *mapping;
> +       struct rb_node *node;
> +
> +       if (!handle)
> +               return;
> +
> +       node = rb_first(&pgt->pkvm_mappings);
> +       while (node) {
> +               mapping = rb_entry(node, struct pkvm_mapping, node);
> +               kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
> +               node = rb_next(node);
> +               rb_erase(&mapping->node, &pgt->pkvm_mappings);
> +               kfree(mapping);
> +       }
> +}
> +
> +int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
> +                          u64 phys, enum kvm_pgtable_prot prot,
> +                          void *mc, enum kvm_pgtable_walk_flags flags)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       struct pkvm_mapping *mapping = NULL;
> +       struct kvm_hyp_memcache *cache = mc;
> +       u64 gfn = addr >> PAGE_SHIFT;
> +       u64 pfn = phys >> PAGE_SHIFT;

Is it worth using the gpa_to_gfn and __phys_to_pfn helpers? Might
obscure rather than help, but something to think about.

> +       int ret;
> +
> +       if (size != PAGE_SIZE)
> +               return -EINVAL;
> +
> +       lockdep_assert_held_write(&kvm->mmu_lock);
> +       ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, prot);
> +       if (ret) {
> +               /* Is the gfn already mapped due to a racing vCPU? */
> +               if (ret == -EPERM)
> +                       return -EAGAIN;
> +       }
> +
> +       swap(mapping, cache->mapping);
> +       mapping->gfn = gfn;
> +       mapping->pfn = pfn;
> +       WARN_ON(rb_find_add(&mapping->node, &pgt->pkvm_mappings, cmp_mappings));

In addition to the warning, is it better to return an error as well?

Cheers,
/fuad


> +       return ret;
> +}
> +
> +int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> +       struct pkvm_mapping *mapping;
> +       int ret = 0;
> +
> +       lockdep_assert_held_write(&kvm->mmu_lock);
> +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
> +               ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
> +               if (WARN_ON(ret))
> +                       break;
> +               rb_erase(&mapping->node, &pgt->pkvm_mappings);
> +               kfree(mapping);
> +       }
> +
> +       return ret;
> +}
> +
> +int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> +       struct pkvm_mapping *mapping;
> +       int ret = 0;
> +
> +       lockdep_assert_held(&kvm->mmu_lock);
> +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
> +               ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn);
> +               if (WARN_ON(ret))
> +                       break;
> +       }
> +
> +       return ret;
> +}
> +
> +int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       struct pkvm_mapping *mapping;
> +
> +       lockdep_assert_held(&kvm->mmu_lock);
> +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
> +               __clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn), PAGE_SIZE);
> +
> +       return 0;
> +}
> +
> +bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold)
> +{
> +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> +       struct pkvm_mapping *mapping;
> +       bool young = false;
> +
> +       lockdep_assert_held(&kvm->mmu_lock);
> +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
> +               young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn,
> +                                          mkold);
> +
> +       return young;
> +}
> +
> +int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
> +                                   enum kvm_pgtable_walk_flags flags)
> +{
> +       return kvm_call_hyp_nvhe(__pkvm_host_relax_perms_guest, addr >> PAGE_SHIFT, prot);
> +}
> +
> +void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
> +                                enum kvm_pgtable_walk_flags flags)
> +{
> +       WARN_ON(kvm_call_hyp_nvhe(__pkvm_host_mkyoung_guest, addr >> PAGE_SHIFT));
> +}
> +
> +void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
> +{
> +       WARN_ON_ONCE(1);
> +}
> +
> +kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
> +                                       enum kvm_pgtable_prot prot, void *mc, bool force_pte)
> +{
> +       WARN_ON_ONCE(1);
> +       return NULL;
> +}
> +
> +int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
> +                             struct kvm_mmu_memory_cache *mc)
> +{
> +       WARN_ON_ONCE(1);
> +       return -EINVAL;
> +}
> --
> 2.47.1.613.gc27f4b7a9f-goog
>

Re: [PATCH v4 17/18] KVM: arm64: Introduce the EL1 pKVM MMU

[Quentin Perret]

On Thursday 19 Dec 2024 at 09:49:31 (+0000), Fuad Tabba wrote:
> Hi Quentin
> 
> On Wed, 18 Dec 2024 at 19:41, Quentin Perret <qperret@google.com> wrote:
> >
> > Introduce a set of helper functions allowing to manipulate the pKVM
> > guest stage-2 page-tables from EL1 using pKVM's HVC interface.
> >
> > Each helper has an exact one-to-one correspondance with the traditional
> > kvm_pgtable_stage2_*() functions from pgtable.c, with a strictly
> > matching prototype. This will ease plumbing later on in mmu.c.
> >
> > These callbacks track the gfn->pfn mappings in a simple rb_tree indexed
> > by IPA in lieu of a page-table. This rb-tree is kept in sync with pKVM's
> > state and is protected by the mmu_lock like a traditional stage-2
> > page-table.
> >
> > Signed-off-by: Quentin Perret <qperret@google.com>
> 
> Minor nits (feel free to ignore). Apart from that, and despite that
> for_each_mapping_in_range_safe macro:
> 
> Tested-by: Fuad Tabba <tabba@google.com>
> Reviewed-by: Fuad Tabba <tabba@google.com>

Thanks!

> > ---
> >  arch/arm64/include/asm/kvm_host.h    |   1 +
> >  arch/arm64/include/asm/kvm_pgtable.h |  23 +--
> >  arch/arm64/include/asm/kvm_pkvm.h    |  26 ++++
> >  arch/arm64/kvm/pkvm.c                | 201 +++++++++++++++++++++++++++
> >  4 files changed, 242 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> > index 1246f1d01dbf..f23f4ea9ec8b 100644
> > --- a/arch/arm64/include/asm/kvm_host.h
> > +++ b/arch/arm64/include/asm/kvm_host.h
> > @@ -85,6 +85,7 @@ void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu);
> >  struct kvm_hyp_memcache {
> >         phys_addr_t head;
> >         unsigned long nr_pages;
> > +       struct pkvm_mapping *mapping; /* only used from EL1 */
> >  };
> >
> >  static inline void push_hyp_memcache(struct kvm_hyp_memcache *mc,
> > diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> > index 04418b5e3004..6b9d274052c7 100644
> > --- a/arch/arm64/include/asm/kvm_pgtable.h
> > +++ b/arch/arm64/include/asm/kvm_pgtable.h
> > @@ -412,15 +412,20 @@ static inline bool kvm_pgtable_walk_lock_held(void)
> >   *                     be used instead of block mappings.
> >   */
> >  struct kvm_pgtable {
> > -       u32                                     ia_bits;
> > -       s8                                      start_level;
> > -       kvm_pteref_t                            pgd;
> > -       struct kvm_pgtable_mm_ops               *mm_ops;
> > -
> > -       /* Stage-2 only */
> > -       struct kvm_s2_mmu                       *mmu;
> > -       enum kvm_pgtable_stage2_flags           flags;
> > -       kvm_pgtable_force_pte_cb_t              force_pte_cb;
> > +       union {
> > +               struct rb_root                                  pkvm_mappings;
> > +               struct {
> > +                       u32                                     ia_bits;
> > +                       s8                                      start_level;
> > +                       kvm_pteref_t                            pgd;
> > +                       struct kvm_pgtable_mm_ops               *mm_ops;
> > +
> > +                       /* Stage-2 only */
> > +                       enum kvm_pgtable_stage2_flags           flags;
> > +                       kvm_pgtable_force_pte_cb_t              force_pte_cb;
> > +               };
> > +       };
> > +       struct kvm_s2_mmu                                       *mmu;
> >  };
> >
> >  /**
> > diff --git a/arch/arm64/include/asm/kvm_pkvm.h b/arch/arm64/include/asm/kvm_pkvm.h
> > index cd56acd9a842..65f988b6fe0d 100644
> > --- a/arch/arm64/include/asm/kvm_pkvm.h
> > +++ b/arch/arm64/include/asm/kvm_pkvm.h
> > @@ -137,4 +137,30 @@ static inline size_t pkvm_host_sve_state_size(void)
> >                         SVE_SIG_REGS_SIZE(sve_vq_from_vl(kvm_host_sve_max_vl)));
> >  }
> >
> > +struct pkvm_mapping {
> > +       struct rb_node node;
> > +       u64 gfn;
> > +       u64 pfn;
> > +};
> > +
> > +int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
> > +                            struct kvm_pgtable_mm_ops *mm_ops);
> > +void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt);
> > +int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size, u64 phys,
> > +                           enum kvm_pgtable_prot prot, void *mc,
> > +                           enum kvm_pgtable_walk_flags flags);
> > +int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size);
> > +int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size);
> > +int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size);
> > +bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold);
> > +int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
> > +                                   enum kvm_pgtable_walk_flags flags);
> > +void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
> > +                                enum kvm_pgtable_walk_flags flags);
> > +int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
> > +                             struct kvm_mmu_memory_cache *mc);
> > +void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level);
> > +kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
> > +                                              enum kvm_pgtable_prot prot, void *mc,
> > +                                              bool force_pte);
> >  #endif /* __ARM64_KVM_PKVM_H__ */
> > diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
> > index 85117ea8f351..930b677eb9b0 100644
> > --- a/arch/arm64/kvm/pkvm.c
> > +++ b/arch/arm64/kvm/pkvm.c
> > @@ -7,6 +7,7 @@
> >  #include <linux/init.h>
> >  #include <linux/kmemleak.h>
> >  #include <linux/kvm_host.h>
> > +#include <asm/kvm_mmu.h>
> >  #include <linux/memblock.h>
> >  #include <linux/mutex.h>
> >  #include <linux/sort.h>
> > @@ -268,3 +269,203 @@ static int __init finalize_pkvm(void)
> >         return ret;
> >  }
> >  device_initcall_sync(finalize_pkvm);
> > +
> > +static int cmp_mappings(struct rb_node *node, const struct rb_node *parent)
> > +{
> > +       struct pkvm_mapping *a = rb_entry(node, struct pkvm_mapping, node);
> > +       struct pkvm_mapping *b = rb_entry(parent, struct pkvm_mapping, node);
> > +
> > +       if (a->gfn < b->gfn)
> > +               return -1;
> > +       if (a->gfn > b->gfn)
> > +               return 1;
> > +       return 0;
> > +}
> > +
> > +static struct rb_node *find_first_mapping_node(struct rb_root *root, u64 gfn)
> > +{
> > +       struct rb_node *node = root->rb_node, *prev = NULL;
> > +       struct pkvm_mapping *mapping;
> > +
> > +       while (node) {
> > +               mapping = rb_entry(node, struct pkvm_mapping, node);
> > +               if (mapping->gfn == gfn)
> > +                       return node;
> > +               prev = node;
> > +               node = (gfn < mapping->gfn) ? node->rb_left : node->rb_right;
> > +       }
> > +
> > +       return prev;
> > +}
> > +
> > +/*
> > + * __tmp is updated to rb_next(__tmp) *before* entering the body of the loop to allow freeing
> > + * of __map inline.
> > + */
> > +#define for_each_mapping_in_range_safe(__pgt, __start, __end, __map)                           \
> > +       for (struct rb_node *__tmp = find_first_mapping_node(&(__pgt)->pkvm_mappings,           \
> > +                                                            ((__start) >> PAGE_SHIFT));        \
> > +            __tmp && ({                                                                        \
> > +                               __map = rb_entry(__tmp, struct pkvm_mapping, node);             \
> > +                               __tmp = rb_next(__tmp);                                         \
> > +                               true;                                                           \
> > +                      });                                                                      \
> > +           )                                                                                   \
> > +               if (__map->gfn < ((__start) >> PAGE_SHIFT))                                     \
> > +                       continue;                                                               \
> > +               else if (__map->gfn >= ((__end) >> PAGE_SHIFT))                                 \
> > +                       break;                                                                  \
> > +               else
> > +
> > +int pkvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu,
> > +                            struct kvm_pgtable_mm_ops *mm_ops)
> > +{
> > +       pgt->pkvm_mappings      = RB_ROOT;
> > +       pgt->mmu                = mmu;
> > +
> > +       return 0;
> > +}
> > +
> > +void pkvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> > +       struct pkvm_mapping *mapping;
> > +       struct rb_node *node;
> > +
> > +       if (!handle)
> > +               return;
> > +
> > +       node = rb_first(&pgt->pkvm_mappings);
> > +       while (node) {
> > +               mapping = rb_entry(node, struct pkvm_mapping, node);
> > +               kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
> > +               node = rb_next(node);
> > +               rb_erase(&mapping->node, &pgt->pkvm_mappings);
> > +               kfree(mapping);
> > +       }
> > +}
> > +
> > +int pkvm_pgtable_stage2_map(struct kvm_pgtable *pgt, u64 addr, u64 size,
> > +                          u64 phys, enum kvm_pgtable_prot prot,
> > +                          void *mc, enum kvm_pgtable_walk_flags flags)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       struct pkvm_mapping *mapping = NULL;
> > +       struct kvm_hyp_memcache *cache = mc;
> > +       u64 gfn = addr >> PAGE_SHIFT;
> > +       u64 pfn = phys >> PAGE_SHIFT;
> 
> Is it worth using the gpa_to_gfn and __phys_to_pfn helpers? Might
> obscure rather than help, but something to think about.

Apparently user_mem_abort() already uses an open coded variant of
gpa_to_gfn(), so I guess it makes sense to be consistent here? I
personally like the open coded variant better because it makes it clear
what this does, but no strong opinion really.

> > +       int ret;
> > +
> > +       if (size != PAGE_SIZE)
> > +               return -EINVAL;
> > +
> > +       lockdep_assert_held_write(&kvm->mmu_lock);
> > +       ret = kvm_call_hyp_nvhe(__pkvm_host_share_guest, pfn, gfn, prot);
> > +       if (ret) {
> > +               /* Is the gfn already mapped due to a racing vCPU? */
> > +               if (ret == -EPERM)
> > +                       return -EAGAIN;
> > +       }
> > +
> > +       swap(mapping, cache->mapping);
> > +       mapping->gfn = gfn;
> > +       mapping->pfn = pfn;
> > +       WARN_ON(rb_find_add(&mapping->node, &pgt->pkvm_mappings, cmp_mappings));
> 
> In addition to the warning, is it better to return an error as well?

Right, returning an error would be fatal for the guest I think, there's
nothing the VMM can do. The WARN alone keeps it limping along a bit
longer. In both case we're in deep trouble because the state is truly
borked.

I'm tempted to leave things as is (because the error path is really
going to be dead code in practice) unless anybody feels strongly about
it.

Cheers,
Quentin

> 
> > +       return ret;
> > +}
> > +
> > +int pkvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> > +       struct pkvm_mapping *mapping;
> > +       int ret = 0;
> > +
> > +       lockdep_assert_held_write(&kvm->mmu_lock);
> > +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
> > +               ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_guest, handle, mapping->gfn);
> > +               if (WARN_ON(ret))
> > +                       break;
> > +               rb_erase(&mapping->node, &pgt->pkvm_mappings);
> > +               kfree(mapping);
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +int pkvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> > +       struct pkvm_mapping *mapping;
> > +       int ret = 0;
> > +
> > +       lockdep_assert_held(&kvm->mmu_lock);
> > +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping) {
> > +               ret = kvm_call_hyp_nvhe(__pkvm_host_wrprotect_guest, handle, mapping->gfn);
> > +               if (WARN_ON(ret))
> > +                       break;
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +int pkvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       struct pkvm_mapping *mapping;
> > +
> > +       lockdep_assert_held(&kvm->mmu_lock);
> > +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
> > +               __clean_dcache_guest_page(pfn_to_kaddr(mapping->pfn), PAGE_SIZE);
> > +
> > +       return 0;
> > +}
> > +
> > +bool pkvm_pgtable_stage2_test_clear_young(struct kvm_pgtable *pgt, u64 addr, u64 size, bool mkold)
> > +{
> > +       struct kvm *kvm = kvm_s2_mmu_to_kvm(pgt->mmu);
> > +       pkvm_handle_t handle = kvm->arch.pkvm.handle;
> > +       struct pkvm_mapping *mapping;
> > +       bool young = false;
> > +
> > +       lockdep_assert_held(&kvm->mmu_lock);
> > +       for_each_mapping_in_range_safe(pgt, addr, addr + size, mapping)
> > +               young |= kvm_call_hyp_nvhe(__pkvm_host_test_clear_young_guest, handle, mapping->gfn,
> > +                                          mkold);
> > +
> > +       return young;
> > +}
> > +
> > +int pkvm_pgtable_stage2_relax_perms(struct kvm_pgtable *pgt, u64 addr, enum kvm_pgtable_prot prot,
> > +                                   enum kvm_pgtable_walk_flags flags)
> > +{
> > +       return kvm_call_hyp_nvhe(__pkvm_host_relax_perms_guest, addr >> PAGE_SHIFT, prot);
> > +}
> > +
> > +void pkvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr,
> > +                                enum kvm_pgtable_walk_flags flags)
> > +{
> > +       WARN_ON(kvm_call_hyp_nvhe(__pkvm_host_mkyoung_guest, addr >> PAGE_SHIFT));
> > +}
> > +
> > +void pkvm_pgtable_stage2_free_unlinked(struct kvm_pgtable_mm_ops *mm_ops, void *pgtable, s8 level)
> > +{
> > +       WARN_ON_ONCE(1);
> > +}
> > +
> > +kvm_pte_t *pkvm_pgtable_stage2_create_unlinked(struct kvm_pgtable *pgt, u64 phys, s8 level,
> > +                                       enum kvm_pgtable_prot prot, void *mc, bool force_pte)
> > +{
> > +       WARN_ON_ONCE(1);
> > +       return NULL;
> > +}
> > +
> > +int pkvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size,
> > +                             struct kvm_mmu_memory_cache *mc)
> > +{
> > +       WARN_ON_ONCE(1);
> > +       return -EINVAL;
> > +}
> > --
> > 2.47.1.613.gc27f4b7a9f-goog
> >

[PATCH v4 18/18] KVM: arm64: Plumb the pKVM MMU in KVM

[Quentin Perret]

Introduce the KVM_PGT_CALL() helper macro to allow switching from the
traditional pgtable code to the pKVM version easily in mmu.c. The cost
of this 'indirection' is expected to be very minimal due to
is_protected_kvm_enabled() being backed by a static key.

With this, everything is in place to allow the delegation of
non-protected guest stage-2 page-tables to pKVM, so let's stop using the
host's kvm_s2_mmu from EL2 and enjoy the ride.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Quentin Perret <qperret@google.com>
---
 arch/arm64/include/asm/kvm_mmu.h   | 16 ++++++
 arch/arm64/kvm/arm.c               |  9 +++-
 arch/arm64/kvm/hyp/nvhe/hyp-main.c |  2 -
 arch/arm64/kvm/mmu.c               | 87 ++++++++++++++++++++----------
 4 files changed, 82 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 66d93e320ec8..d116ab4230e8 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -353,6 +353,22 @@ static inline bool kvm_is_nested_s2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu)
 	return &kvm->arch.mmu != mmu;
 }
 
+static inline void kvm_fault_lock(struct kvm *kvm)
+{
+	if (is_protected_kvm_enabled())
+		write_lock(&kvm->mmu_lock);
+	else
+		read_lock(&kvm->mmu_lock);
+}
+
+static inline void kvm_fault_unlock(struct kvm *kvm)
+{
+	if (is_protected_kvm_enabled())
+		write_unlock(&kvm->mmu_lock);
+	else
+		read_unlock(&kvm->mmu_lock);
+}
+
 #ifdef CONFIG_PTDUMP_STAGE2_DEBUGFS
 void kvm_s2_ptdump_create_debugfs(struct kvm *kvm);
 #else
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 55cc62b2f469..9bcbc7b8ed38 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -502,7 +502,10 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
 {
-	kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	if (!is_protected_kvm_enabled())
+		kvm_mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
+	else
+		free_hyp_memcache(&vcpu->arch.pkvm_memcache);
 	kvm_timer_vcpu_terminate(vcpu);
 	kvm_pmu_vcpu_destroy(vcpu);
 	kvm_vgic_vcpu_destroy(vcpu);
@@ -574,6 +577,9 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 	struct kvm_s2_mmu *mmu;
 	int *last_ran;
 
+	if (is_protected_kvm_enabled())
+		goto nommu;
+
 	if (vcpu_has_nv(vcpu))
 		kvm_vcpu_load_hw_mmu(vcpu);
 
@@ -594,6 +600,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		*last_ran = vcpu->vcpu_idx;
 	}
 
+nommu:
 	vcpu->cpu = cpu;
 
 	kvm_vgic_load(vcpu);
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index 130f5f23bcb5..258d572eed62 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -103,8 +103,6 @@ static void flush_hyp_vcpu(struct pkvm_hyp_vcpu *hyp_vcpu)
 	/* Limit guest vector length to the maximum supported by the host.  */
 	hyp_vcpu->vcpu.arch.sve_max_vl	= min(host_vcpu->arch.sve_max_vl, kvm_host_sve_max_vl);
 
-	hyp_vcpu->vcpu.arch.hw_mmu	= host_vcpu->arch.hw_mmu;
-
 	hyp_vcpu->vcpu.arch.mdcr_el2	= host_vcpu->arch.mdcr_el2;
 	hyp_vcpu->vcpu.arch.hcr_el2 &= ~(HCR_TWI | HCR_TWE);
 	hyp_vcpu->vcpu.arch.hcr_el2 |= READ_ONCE(host_vcpu->arch.hcr_el2) &
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index 641e4fec1659..9403524c11c6 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -15,6 +15,7 @@
 #include <asm/kvm_arm.h>
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
+#include <asm/kvm_pkvm.h>
 #include <asm/kvm_ras.h>
 #include <asm/kvm_asm.h>
 #include <asm/kvm_emulate.h>
@@ -31,6 +32,8 @@ static phys_addr_t __ro_after_init hyp_idmap_vector;
 
 static unsigned long __ro_after_init io_map_base;
 
+#define KVM_PGT_FN(fn)		(!is_protected_kvm_enabled() ? fn : p ## fn)
+
 static phys_addr_t __stage2_range_addr_end(phys_addr_t addr, phys_addr_t end,
 					   phys_addr_t size)
 {
@@ -147,7 +150,7 @@ static int kvm_mmu_split_huge_pages(struct kvm *kvm, phys_addr_t addr,
 			return -EINVAL;
 
 		next = __stage2_range_addr_end(addr, end, chunk_size);
-		ret = kvm_pgtable_stage2_split(pgt, addr, next - addr, cache);
+		ret = KVM_PGT_FN(kvm_pgtable_stage2_split)(pgt, addr, next - addr, cache);
 		if (ret)
 			break;
 	} while (addr = next, addr != end);
@@ -168,15 +171,23 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
  */
 int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
 {
-	kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
+	if (is_protected_kvm_enabled())
+		kvm_call_hyp_nvhe(__pkvm_tlb_flush_vmid, kvm->arch.pkvm.handle);
+	else
+		kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
 	return 0;
 }
 
 int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
 				      gfn_t gfn, u64 nr_pages)
 {
-	kvm_tlb_flush_vmid_range(&kvm->arch.mmu,
-				gfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
+	u64 size = nr_pages << PAGE_SHIFT;
+	u64 addr = gfn << PAGE_SHIFT;
+
+	if (is_protected_kvm_enabled())
+		kvm_call_hyp_nvhe(__pkvm_tlb_flush_vmid, kvm->arch.pkvm.handle);
+	else
+		kvm_tlb_flush_vmid_range(&kvm->arch.mmu, addr, size);
 	return 0;
 }
 
@@ -225,7 +236,7 @@ static void stage2_free_unlinked_table_rcu_cb(struct rcu_head *head)
 	void *pgtable = page_to_virt(page);
 	s8 level = page_private(page);
 
-	kvm_pgtable_stage2_free_unlinked(&kvm_s2_mm_ops, pgtable, level);
+	KVM_PGT_FN(kvm_pgtable_stage2_free_unlinked)(&kvm_s2_mm_ops, pgtable, level);
 }
 
 static void stage2_free_unlinked_table(void *addr, s8 level)
@@ -324,7 +335,7 @@ 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,
+	WARN_ON(stage2_apply_range(mmu, start, end, KVM_PGT_FN(kvm_pgtable_stage2_unmap),
 				   may_block));
 }
 
@@ -336,7 +347,7 @@ void kvm_stage2_unmap_range(struct kvm_s2_mmu *mmu, phys_addr_t start,
 
 void kvm_stage2_flush_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
 {
-	stage2_apply_range_resched(mmu, addr, end, kvm_pgtable_stage2_flush);
+	stage2_apply_range_resched(mmu, addr, end, KVM_PGT_FN(kvm_pgtable_stage2_flush));
 }
 
 static void stage2_flush_memslot(struct kvm *kvm,
@@ -942,10 +953,14 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 		return -ENOMEM;
 
 	mmu->arch = &kvm->arch;
-	err = kvm_pgtable_stage2_init(pgt, mmu, &kvm_s2_mm_ops);
+	err = KVM_PGT_FN(kvm_pgtable_stage2_init)(pgt, mmu, &kvm_s2_mm_ops);
 	if (err)
 		goto out_free_pgtable;
 
+	mmu->pgt = pgt;
+	if (is_protected_kvm_enabled())
+		return 0;
+
 	mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran));
 	if (!mmu->last_vcpu_ran) {
 		err = -ENOMEM;
@@ -959,7 +974,6 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 	mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT;
 	mmu->split_page_cache.gfp_zero = __GFP_ZERO;
 
-	mmu->pgt = pgt;
 	mmu->pgd_phys = __pa(pgt->pgd);
 
 	if (kvm_is_nested_s2_mmu(kvm, mmu))
@@ -968,7 +982,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t
 	return 0;
 
 out_destroy_pgtable:
-	kvm_pgtable_stage2_destroy(pgt);
+	KVM_PGT_FN(kvm_pgtable_stage2_destroy)(pgt);
 out_free_pgtable:
 	kfree(pgt);
 	return err;
@@ -1065,7 +1079,7 @@ void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
 	write_unlock(&kvm->mmu_lock);
 
 	if (pgt) {
-		kvm_pgtable_stage2_destroy(pgt);
+		KVM_PGT_FN(kvm_pgtable_stage2_destroy)(pgt);
 		kfree(pgt);
 	}
 }
@@ -1082,9 +1096,11 @@ static void *hyp_mc_alloc_fn(void *unused)
 
 void free_hyp_memcache(struct kvm_hyp_memcache *mc)
 {
-	if (is_protected_kvm_enabled())
-		__free_hyp_memcache(mc, hyp_mc_free_fn,
-				    kvm_host_va, NULL);
+	if (!is_protected_kvm_enabled())
+		return;
+
+	kfree(mc->mapping);
+	__free_hyp_memcache(mc, hyp_mc_free_fn, kvm_host_va, NULL);
 }
 
 int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
@@ -1092,6 +1108,12 @@ int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
 	if (!is_protected_kvm_enabled())
 		return 0;
 
+	if (!mc->mapping) {
+		mc->mapping = kzalloc(sizeof(struct pkvm_mapping), GFP_KERNEL_ACCOUNT);
+		if (!mc->mapping)
+			return -ENOMEM;
+	}
+
 	return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn,
 				    kvm_host_pa, NULL);
 }
@@ -1130,8 +1152,8 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
 			break;
 
 		write_lock(&kvm->mmu_lock);
-		ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot,
-					     &cache, 0);
+		ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, addr, PAGE_SIZE,
+				 pa, prot, &cache, 0);
 		write_unlock(&kvm->mmu_lock);
 		if (ret)
 			break;
@@ -1151,7 +1173,7 @@ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
  */
 void kvm_stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
 {
-	stage2_apply_range_resched(mmu, addr, end, kvm_pgtable_stage2_wrprotect);
+	stage2_apply_range_resched(mmu, addr, end, KVM_PGT_FN(kvm_pgtable_stage2_wrprotect));
 }
 
 /**
@@ -1442,9 +1464,9 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	unsigned long mmu_seq;
 	phys_addr_t ipa = fault_ipa;
 	struct kvm *kvm = vcpu->kvm;
-	struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
 	struct vm_area_struct *vma;
 	short vma_shift;
+	void *memcache;
 	gfn_t gfn;
 	kvm_pfn_t pfn;
 	bool logging_active = memslot_is_logging(memslot);
@@ -1472,8 +1494,15 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * and a write fault needs to collapse a block entry into a table.
 	 */
 	if (!fault_is_perm || (logging_active && write_fault)) {
-		ret = kvm_mmu_topup_memory_cache(memcache,
-						 kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu));
+		int min_pages = kvm_mmu_cache_min_pages(vcpu->arch.hw_mmu);
+
+		if (!is_protected_kvm_enabled()) {
+			memcache = &vcpu->arch.mmu_page_cache;
+			ret = kvm_mmu_topup_memory_cache(memcache, min_pages);
+		} else {
+			memcache = &vcpu->arch.pkvm_memcache;
+			ret = topup_hyp_memcache(memcache, min_pages);
+		}
 		if (ret)
 			return ret;
 	}
@@ -1494,7 +1523,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 	 * logging_active is guaranteed to never be true for VM_PFNMAP
 	 * memslots.
 	 */
-	if (logging_active) {
+	if (logging_active || is_protected_kvm_enabled()) {
 		force_pte = true;
 		vma_shift = PAGE_SHIFT;
 	} else {
@@ -1634,7 +1663,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		prot |= kvm_encode_nested_level(nested);
 	}
 
-	read_lock(&kvm->mmu_lock);
+	kvm_fault_lock(kvm);
 	pgt = vcpu->arch.hw_mmu->pgt;
 	if (mmu_invalidate_retry(kvm, mmu_seq)) {
 		ret = -EAGAIN;
@@ -1696,16 +1725,16 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		 * PTE, which will be preserved.
 		 */
 		prot &= ~KVM_NV_GUEST_MAP_SZ;
-		ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot, flags);
+		ret = KVM_PGT_FN(kvm_pgtable_stage2_relax_perms)(pgt, fault_ipa, prot, flags);
 	} else {
-		ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
+		ret = KVM_PGT_FN(kvm_pgtable_stage2_map)(pgt, fault_ipa, vma_pagesize,
 					     __pfn_to_phys(pfn), prot,
 					     memcache, flags);
 	}
 
 out_unlock:
 	kvm_release_faultin_page(kvm, page, !!ret, writable);
-	read_unlock(&kvm->mmu_lock);
+	kvm_fault_unlock(kvm);
 
 	/* Mark the page dirty only if the fault is handled successfully */
 	if (writable && !ret)
@@ -1724,7 +1753,7 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
 
 	read_lock(&vcpu->kvm->mmu_lock);
 	mmu = vcpu->arch.hw_mmu;
-	kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa, flags);
+	KVM_PGT_FN(kvm_pgtable_stage2_mkyoung)(mmu->pgt, fault_ipa, flags);
 	read_unlock(&vcpu->kvm->mmu_lock);
 }
 
@@ -1764,7 +1793,7 @@ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
 		}
 
 		/* Falls between the IPA range and the PARange? */
-		if (fault_ipa >= BIT_ULL(vcpu->arch.hw_mmu->pgt->ia_bits)) {
+		if (fault_ipa >= BIT_ULL(VTCR_EL2_IPA(vcpu->arch.hw_mmu->vtcr))) {
 			fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
 
 			if (is_iabt)
@@ -1930,7 +1959,7 @@ bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 	if (!kvm->arch.mmu.pgt)
 		return false;
 
-	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
+	return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
 						   range->start << PAGE_SHIFT,
 						   size, true);
 	/*
@@ -1946,7 +1975,7 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
 	if (!kvm->arch.mmu.pgt)
 		return false;
 
-	return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
+	return KVM_PGT_FN(kvm_pgtable_stage2_test_clear_young)(kvm->arch.mmu.pgt,
 						   range->start << PAGE_SHIFT,
 						   size, false);
 }
-- 
2.47.1.613.gc27f4b7a9f-goog

Re: [PATCH v4 00/18] KVM: arm64: Non-protected guest stage-2 support for pKVM

[Marc Zyngier]

On Wed, 18 Dec 2024 19:40:41 +0000, Quentin Perret wrote:
> This is the v4 of the series adding support for non-protected guests
> stage-2 to pKVM. Please refer to v1 for all the context:
> 
>   https://lore.kernel.org/kvmarm/20241104133204.85208-1-qperret@google.com/
> 
> Please note that in its current form, this series has two main
> limitations that will be addressed separately:
> 
> [...]

Applied to next, thanks!

[01/18] KVM: arm64: Change the layout of enum pkvm_page_state
        commit: a1a1f1ff1f28d52deb39aa29b89663de2afefd67
[02/18] KVM: arm64: Move enum pkvm_page_state to memory.h
        commit: d4fc42a479c8e913fd61dbb432e67f35587c336a
[03/18] KVM: arm64: Make hyp_page::order a u8
        commit: b35875d466ad3cb08866eac067cca0581d4293d7
[04/18] KVM: arm64: Move host page ownership tracking to the hyp vmemmap
        commit: e94a7dea2972bd9a5ee3ed4312f7198370969407
[05/18] KVM: arm64: Pass walk flags to kvm_pgtable_stage2_mkyoung
        commit: 5398ddc5c90bd418b90d859e9267aa39399021af
[06/18] KVM: arm64: Pass walk flags to kvm_pgtable_stage2_relax_perms
        commit: e279c25d78d6729e39a0221c98185bd0e7aa0c99
[07/18] KVM: arm64: Make kvm_pgtable_stage2_init() a static inline function
        commit: c77e5181fed54b25d489eb7d2ccb5c1c72a1063c
[08/18] KVM: arm64: Add {get,put}_pkvm_hyp_vm() helpers
        commit: 99996d575ee69d4327bad98a0148729b73dde23a
[09/18] KVM: arm64: Introduce __pkvm_vcpu_{load,put}()
        commit: f7d03fcbf1f482069e9afac55b17de3bd323b8f6
[10/18] KVM: arm64: Introduce __pkvm_host_share_guest()
        commit: d0bd3e6570aee42766e7bd884734ae078667ea1e
[11/18] KVM: arm64: Introduce __pkvm_host_unshare_guest()
        commit: 72db3d3fbaa77ba649201c9e9f9d1a54fa76b217
[12/18] KVM: arm64: Introduce __pkvm_host_relax_guest_perms()
        commit: 34884a0a4a53f9544f78e7e9556cb4d202e170d5
[13/18] KVM: arm64: Introduce __pkvm_host_wrprotect_guest()
        commit: 26117e4c636c813be4fa31e9ec9410b7d02ced5c
[14/18] KVM: arm64: Introduce __pkvm_host_test_clear_young_guest()
        commit: 56ab4de37f4e13231e964cf7fa304818f791fea7
[15/18] KVM: arm64: Introduce __pkvm_host_mkyoung_guest()
        commit: 76f0b18b3db57868fb0cabe691201aad3085b712
[16/18] KVM: arm64: Introduce __pkvm_tlb_flush_vmid()
        commit: 0adce4d42f249b1701c136907055d9b12f8f6e1c
[17/18] KVM: arm64: Introduce the EL1 pKVM MMU
        commit: e912efed485a4c50bdc3934ae647e257ef568ef6
[18/18] KVM: arm64: Plumb the pKVM MMU in KVM
        commit: fce886a6020734d6253c2c5a3bc285e385cc5496

Cheers,

	M.
-- 
Without deviation from the norm, progress is not possible.