[PATCH v4 08/15] arm64: kvm: Duplicate hyp/tlb.c for VHE/nVHE

David Brazdil
2020-06-25T13:14:52Z

tlb.c contains code for flushing the TLB, with code shared between VHE/nVHE.
Because common code is small, duplicate tlb.c and specialize each copy for
VHE/nVHE.

Signed-off-by: David Brazdil <dbrazdil@google.com>
---
arch/arm64/kernel/image-vars.h | 14 +--
arch/arm64/kvm/hyp/Makefile | 2 +-
arch/arm64/kvm/hyp/nvhe/Makefile | 2 +-
arch/arm64/kvm/hyp/{ => nvhe}/tlb.c | 94 +---------------
arch/arm64/kvm/hyp/vhe/Makefile | 2 +-
arch/arm64/kvm/hyp/vhe/tlb.c | 162 ++++++++++++++++++++++++++++
6 files changed, 178 insertions(+), 98 deletions(-)
rename arch/arm64/kvm/hyp/{ => nvhe}/tlb.c (62%)
create mode 100644 arch/arm64/kvm/hyp/vhe/tlb.c

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index c3643df22a9b..5d7cb61bfa9a 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -81,12 +81,6 @@ KVM_NVHE_ALIAS(__kvm_enable_ssbs);
/* Symbols defined in timer-sr.c (not yet compiled with nVHE build rules). */
KVM_NVHE_ALIAS(__kvm_timer_set_cntvoff);

-/* Symbols defined in tlb.c (not yet compiled with nVHE build rules). */
-KVM_NVHE_ALIAS(__kvm_flush_vm_context);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_local_vmid);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_vmid);
-KVM_NVHE_ALIAS(__kvm_tlb_flush_vmid_ipa);
-
/* Symbols defined in vgic-v3-sr.c (not yet compiled with nVHE build rules). */
KVM_NVHE_ALIAS(__vgic_v3_get_ich_vtr_el2);
KVM_NVHE_ALIAS(__vgic_v3_init_lrs);
@@ -113,6 +107,14 @@ KVM_NVHE_ALIAS(panic);
/* Vectors installed by hyp-init on reset HVC. */
KVM_NVHE_ALIAS(__hyp_stub_vectors);

+/* Kernel symbol used by icache_is_vpipt(). */
+KVM_NVHE_ALIAS(__icache_flags);
+
+/* Kernel symbols needed for cpus_have_final/const_caps checks. */
+KVM_NVHE_ALIAS(arm64_const_caps_ready);
+KVM_NVHE_ALIAS(cpu_hwcap_keys);
+KVM_NVHE_ALIAS(cpu_hwcaps);
+
#endif /* CONFIG_KVM */

#endif /* __ARM64_KERNEL_IMAGE_VARS_H */
diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index 8b0cf85080b5..87d3cce2b26e 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -14,7 +14,7 @@ obj-$(CONFIG_KVM) += hyp.o vhe/ nvhe/
obj-$(CONFIG_KVM_INDIRECT_VECTORS) += smccc_wa.o

hyp-y := vgic-v3-sr.o timer-sr.o aarch32.o vgic-v2-cpuif-proxy.o sysreg-sr.o \
- debug-sr.o entry.o switch.o fpsimd.o tlb.o
+ debug-sr.o entry.o switch.o fpsimd.o

# KVM code is run at a different exception code with a different map, so
# compiler instrumentation that inserts callbacks or checks into the code may
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index bf2d8dea5400..a5316e97d373 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -6,7 +6,7 @@
asflags-y := -D__KVM_NVHE_HYPERVISOR__
ccflags-y := -D__KVM_NVHE_HYPERVISOR__

-obj-y := hyp-init.o ../hyp-entry.o
+obj-y := tlb.o hyp-init.o ../hyp-entry.o

obj-y := $(patsubst %.o,%.hyp.o,$(obj-y))
extra-y := $(patsubst %.hyp.o,%.hyp.tmp.o,$(obj-y))
diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/nvhe/tlb.c
similarity index 62%
rename from arch/arm64/kvm/hyp/tlb.c
rename to arch/arm64/kvm/hyp/nvhe/tlb.c
index d063a576d511..9513ad41db9a 100644
--- a/arch/arm64/kvm/hyp/tlb.c
+++ b/arch/arm64/kvm/hyp/nvhe/tlb.c
@@ -4,8 +4,6 @@
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/

-#include <linux/irqflags.h>
-
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/tlbflush.h>
@@ -16,52 +14,8 @@ struct tlb_inv_context {
u64 sctlr;
};

-static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,
- struct tlb_inv_context *cxt)
-{
- u64 val;
-
- local_irq_save(cxt->flags);
-
- if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
- /*
- * For CPUs that are affected by ARM errata 1165522 or 1530923,
- * we cannot trust stage-1 to be in a correct state at that
- * point. Since we do not want to force a full load of the
- * vcpu state, we prevent the EL1 page-table walker to
- * allocate new TLBs. This is done by setting the EPD bits
- * in the TCR_EL1 register. We also need to prevent it to
- * allocate IPA->PA walks, so we enable the S1 MMU...
- */
- val = cxt->tcr = read_sysreg_el1(SYS_TCR);
- val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
- write_sysreg_el1(val, SYS_TCR);
- val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
- val |= SCTLR_ELx_M;
- write_sysreg_el1(val, SYS_SCTLR);
- }
-
- /*
- * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
- * most TLB operations target EL2/EL0. In order to affect the
- * guest TLBs (EL1/EL0), we need to change one of these two
- * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
- * let's flip TGE before executing the TLB operation.
- *
- * ARM erratum 1165522 requires some special handling (again),
- * as we need to make sure both stages of translation are in
- * place before clearing TGE. __load_guest_stage2() already
- * has an ISB in order to deal with this.
- */
- __load_guest_stage2(kvm);
- val = read_sysreg(hcr_el2);
- val &= ~HCR_TGE;
- write_sysreg(val, hcr_el2);
- isb();
-}
-
-static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
- struct tlb_inv_context *cxt)
+static void __hyp_text __tlb_switch_to_guest(struct kvm *kvm,
+ struct tlb_inv_context *cxt)
{
if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
u64 val;
@@ -84,37 +38,8 @@ static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT));
}

-static void __hyp_text __tlb_switch_to_guest(struct kvm *kvm,
- struct tlb_inv_context *cxt)
-{
- if (has_vhe())
- __tlb_switch_to_guest_vhe(kvm, cxt);
- else
- __tlb_switch_to_guest_nvhe(kvm, cxt);
-}
-
-static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm,
- struct tlb_inv_context *cxt)
-{
- /*
- * We're done with the TLB operation, let's restore the host's
- * view of HCR_EL2.
- */
- write_sysreg(0, vttbr_el2);
- write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
- isb();
-
- if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
- /* Restore the registers to what they were */
- write_sysreg_el1(cxt->tcr, SYS_TCR);
- write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
- }
-
- local_irq_restore(cxt->flags);
-}
-
-static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
- struct tlb_inv_context *cxt)
+static void __hyp_text __tlb_switch_to_host(struct kvm *kvm,
+ struct tlb_inv_context *cxt)
{
write_sysreg(0, vttbr_el2);

@@ -126,15 +51,6 @@ static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
}
}

-static void __hyp_text __tlb_switch_to_host(struct kvm *kvm,
- struct tlb_inv_context *cxt)
-{
- if (has_vhe())
- __tlb_switch_to_host_vhe(kvm, cxt);
- else
- __tlb_switch_to_host_nvhe(kvm, cxt);
-}
-
void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
{
struct tlb_inv_context cxt;
@@ -183,7 +99,7 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
* The moral of this story is: if you have a VPIPT I-cache, then
* you should be running with VHE enabled.
*/
- if (!has_vhe() && icache_is_vpipt())
+ if (icache_is_vpipt())
__flush_icache_all();

__tlb_switch_to_host(kvm, &cxt);
diff --git a/arch/arm64/kvm/hyp/vhe/Makefile b/arch/arm64/kvm/hyp/vhe/Makefile
index 323029e02b4e..704140fc5d66 100644
--- a/arch/arm64/kvm/hyp/vhe/Makefile
+++ b/arch/arm64/kvm/hyp/vhe/Makefile
@@ -6,7 +6,7 @@
asflags-y := -D__KVM_VHE_HYPERVISOR__
ccflags-y := -D__KVM_VHE_HYPERVISOR__

-obj-y := ../hyp-entry.o
+obj-y := tlb.o ../hyp-entry.o

# KVM code is run at a different exception code with a different map, so
# compiler instrumentation that inserts callbacks or checks into the code may
diff --git a/arch/arm64/kvm/hyp/vhe/tlb.c b/arch/arm64/kvm/hyp/vhe/tlb.c
new file mode 100644
index 000000000000..35e8e112ba28
--- /dev/null
+++ b/arch/arm64/kvm/hyp/vhe/tlb.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2015 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ */
+
+#include <linux/irqflags.h>
+
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <asm/tlbflush.h>
+
+struct tlb_inv_context {
+ unsigned long flags;
+ u64 tcr;
+ u64 sctlr;
+};
+
+static void __tlb_switch_to_guest(struct kvm *kvm, struct tlb_inv_context *cxt)
+{
+ u64 val;
+
+ local_irq_save(cxt->flags);
+
+ if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
+ /*
+ * For CPUs that are affected by ARM errata 1165522 or 1530923,
+ * we cannot trust stage-1 to be in a correct state at that
+ * point. Since we do not want to force a full load of the
+ * vcpu state, we prevent the EL1 page-table walker to
+ * allocate new TLBs. This is done by setting the EPD bits
+ * in the TCR_EL1 register. We also need to prevent it to
+ * allocate IPA->PA walks, so we enable the S1 MMU...
+ */
+ val = cxt->tcr = read_sysreg_el1(SYS_TCR);
+ val |= TCR_EPD1_MASK | TCR_EPD0_MASK;
+ write_sysreg_el1(val, SYS_TCR);
+ val = cxt->sctlr = read_sysreg_el1(SYS_SCTLR);
+ val |= SCTLR_ELx_M;
+ write_sysreg_el1(val, SYS_SCTLR);
+ }
+
+ /*
+ * With VHE enabled, we have HCR_EL2.{E2H,TGE} = {1,1}, and
+ * most TLB operations target EL2/EL0. In order to affect the
+ * guest TLBs (EL1/EL0), we need to change one of these two
+ * bits. Changing E2H is impossible (goodbye TTBR1_EL2), so
+ * let's flip TGE before executing the TLB operation.
+ *
+ * ARM erratum 1165522 requires some special handling (again),
+ * as we need to make sure both stages of translation are in
+ * place before clearing TGE. __load_guest_stage2() already
+ * has an ISB in order to deal with this.
+ */
+ __load_guest_stage2(kvm);
+ val = read_sysreg(hcr_el2);
+ val &= ~HCR_TGE;
+ write_sysreg(val, hcr_el2);
+ isb();
+}
+
+static void __tlb_switch_to_host(struct kvm *kvm, struct tlb_inv_context *cxt)
+{
+ /*
+ * We're done with the TLB operation, let's restore the host's
+ * view of HCR_EL2.
+ */
+ write_sysreg(0, vttbr_el2);
+ write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
+ isb();
+
+ if (cpus_have_final_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
+ /* Restore the registers to what they were */
+ write_sysreg_el1(cxt->tcr, SYS_TCR);
+ write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
+ }
+
+ local_irq_restore(cxt->flags);
+}
+
+void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
+{
+ struct tlb_inv_context cxt;
+
+ dsb(ishst);
+
+ /* Switch to requested VMID */
+ kvm = kern_hyp_va(kvm);
+ __tlb_switch_to_guest(kvm, &cxt);
+
+ /*
+ * We could do so much better if we had the VA as well.
+ * Instead, we invalidate Stage-2 for this IPA, and the
+ * whole of Stage-1. Weep...
+ */
+ ipa >>= 12;
+ __tlbi(ipas2e1is, ipa);
+
+ /*
+ * We have to ensure completion of the invalidation at Stage-2,
+ * since a table walk on another CPU could refill a TLB with a
+ * complete (S1 + S2) walk based on the old Stage-2 mapping if
+ * the Stage-1 invalidation happened first.
+ */
+ dsb(ish);
+ __tlbi(vmalle1is);
+ dsb(ish);
+ isb();
+
+ __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_tlb_flush_vmid(struct kvm *kvm)
+{
+ struct tlb_inv_context cxt;
+
+ dsb(ishst);
+
+ /* Switch to requested VMID */
+ __tlb_switch_to_guest(kvm, &cxt);
+
+ __tlbi(vmalls12e1is);
+ dsb(ish);
+ isb();
+
+ __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu)
+{
+ struct kvm *kvm = vcpu->kvm;
+ struct tlb_inv_context cxt;
+
+ /* Switch to requested VMID */
+ __tlb_switch_to_guest(kvm, &cxt);
+
+ __tlbi(vmalle1);
+ dsb(nsh);
+ isb();
+
+ __tlb_switch_to_host(kvm, &cxt);
+}
+
+void __kvm_flush_vm_context(void)
+{
+ dsb(ishst);
+ __tlbi(alle1is);
+
+ /*
+ * VIPT and PIPT caches are not affected by VMID, so no maintenance
+ * is necessary across a VMID rollover.
+ *
+ * VPIPT caches constrain lookup and maintenance to the active VMID,
+ * so we need to invalidate lines with a stale VMID to avoid an ABA
+ * race after multiple rollovers.
+ *
+ */
+ if (icache_is_vpipt())
+ asm volatile("ic ialluis");
+
+ dsb(ish);
+}
--
2.27.0