| Message ID | 20210621111716.37157-3-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | MTE support for KVM guest | expand |
Hi, On Mon, Jun 21, 2021 at 12:18 PM Steven Price <steven.price@arm.com> wrote: > > Add a new VM feature 'KVM_ARM_CAP_MTE' which enables memory tagging > for a VM. This will expose the feature to the guest and automatically > tag memory pages touched by the VM as PG_mte_tagged (and clear the tag > storage) to ensure that the guest cannot see stale tags, and so that > the tags are correctly saved/restored across swap. > > Actually exposing the new capability to user space happens in a later > patch. > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > Signed-off-by: Steven Price <steven.price@arm.com> > --- > arch/arm64/include/asm/kvm_emulate.h | 3 ++ > arch/arm64/include/asm/kvm_host.h | 3 ++ > arch/arm64/kvm/hyp/exception.c | 3 +- > arch/arm64/kvm/mmu.c | 64 +++++++++++++++++++++++++++- > arch/arm64/kvm/sys_regs.c | 7 +++ > include/uapi/linux/kvm.h | 1 + > 6 files changed, 79 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > index 01b9857757f2..fd418955e31e 100644 > --- a/arch/arm64/include/asm/kvm_emulate.h > +++ b/arch/arm64/include/asm/kvm_emulate.h > @@ -84,6 +84,9 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) > if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) || > vcpu_el1_is_32bit(vcpu)) > vcpu->arch.hcr_el2 |= HCR_TID2; > + > + if (kvm_has_mte(vcpu->kvm)) > + vcpu->arch.hcr_el2 |= HCR_ATA; > } > > static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu) > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 7cd7d5c8c4bc..afaa5333f0e4 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -132,6 +132,8 @@ struct kvm_arch { > > u8 pfr0_csv2; > u8 pfr0_csv3; > + /* Memory Tagging Extension enabled for the guest */ > + bool mte_enabled; > }; nit: newline before the comment/new member > > struct kvm_vcpu_fault_info { > @@ -769,6 +771,7 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); > #define kvm_arm_vcpu_sve_finalized(vcpu) \ > ((vcpu)->arch.flags & KVM_ARM64_VCPU_SVE_FINALIZED) > > +#define kvm_has_mte(kvm) (system_supports_mte() && (kvm)->arch.mte_enabled) > #define kvm_vcpu_has_pmu(vcpu) \ > (test_bit(KVM_ARM_VCPU_PMU_V3, (vcpu)->arch.features)) > > diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c > index 11541b94b328..0418399e0a20 100644 > --- a/arch/arm64/kvm/hyp/exception.c > +++ b/arch/arm64/kvm/hyp/exception.c > @@ -112,7 +112,8 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, > new |= (old & PSR_C_BIT); > new |= (old & PSR_V_BIT); > > - // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests) > + if (kvm_has_mte(vcpu->kvm)) > + new |= PSR_TCO_BIT; > > new |= (old & PSR_DIT_BIT); > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > index c10207fed2f3..52326b739357 100644 > --- a/arch/arm64/kvm/mmu.c > +++ b/arch/arm64/kvm/mmu.c > @@ -822,6 +822,45 @@ transparent_hugepage_adjust(struct kvm_memory_slot *memslot, > return PAGE_SIZE; > } > > +/* > + * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be > + * able to see the page's tags and therefore they must be initialised first. If > + * PG_mte_tagged is set, tags have already been initialised. > + * > + * The race in the test/set of the PG_mte_tagged flag is handled by: > + * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs > + * racing to santise the same page > + * - mmap_lock protects between a VM faulting a page in and the VMM performing > + * an mprotect() to add VM_MTE > + */ > +static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, > + unsigned long size) > +{ > + unsigned long i, nr_pages = size >> PAGE_SHIFT; > + struct page *page; > + > + if (!kvm_has_mte(kvm)) > + return 0; > + > + /* > + * pfn_to_online_page() is used to reject ZONE_DEVICE pages > + * that may not support tags. > + */ > + page = pfn_to_online_page(pfn); > + > + if (!page) > + return -EFAULT; > + > + for (i = 0; i < nr_pages; i++, page++) { > + if (!test_bit(PG_mte_tagged, &page->flags)) { > + mte_clear_page_tags(page_address(page)); > + set_bit(PG_mte_tagged, &page->flags); > + } > + } > + > + return 0; > +} > + > static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > struct kvm_memory_slot *memslot, unsigned long hva, > unsigned long fault_status) > @@ -971,8 +1010,18 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > if (writable) > prot |= KVM_PGTABLE_PROT_W; > > - if (fault_status != FSC_PERM && !device) > + if (fault_status != FSC_PERM && !device) { > + /* Check the VMM hasn't introduced a new VM_SHARED VMA */ > + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) { > + ret = -EFAULT; > + goto out_unlock; > + } > + ret = sanitise_mte_tags(kvm, pfn, vma_pagesize); > + if (ret) > + goto out_unlock; > + nit: Would it make sense to bring in sanitise_mte_tags under the kvm_has_mte. I know that a check is done in kvm_has_mte as well, but since you're already checking, it might make the code a bit clearer. > clean_dcache_guest_page(pfn, vma_pagesize); > + } > > if (exec_fault) { > prot |= KVM_PGTABLE_PROT_X; > @@ -1168,12 +1217,17 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) > bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > { > kvm_pfn_t pfn = pte_pfn(range->pte); > + int ret; > > if (!kvm->arch.mmu.pgt) > return false; > > WARN_ON(range->end - range->start != 1); > > + ret = sanitise_mte_tags(kvm, pfn, PAGE_SIZE); > + if (ret) > + return false; > + > /* > * We've moved a page around, probably through CoW, so let's treat it > * just like a translation fault and clean the cache to the PoC. > @@ -1381,6 +1435,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, > if (!vma) > break; > > + /* > + * VM_SHARED mappings are not allowed with MTE to avoid races > + * when updating the PG_mte_tagged page flag, see > + * sanitise_mte_tags for more details. > + */ > + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) > + return -EINVAL; > + > /* > * Take the intersection of this VMA with the memory region > */ > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 1a7968ad078c..36f67f8deae1 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > @@ -1047,6 +1047,13 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, > break; > case SYS_ID_AA64PFR1_EL1: > val &= ~FEATURE(ID_AA64PFR1_MTE); > + if (kvm_has_mte(vcpu->kvm)) { > + u64 pfr, mte; > + > + pfr = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1); nit: why reread the sanitized register? wouldn't it be clearer to rework the masking of the val and the check for kvm_has_mte? Cheers, /fuad > + mte = cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR1_MTE_SHIFT); > + val |= FIELD_PREP(FEATURE(ID_AA64PFR1_MTE), mte); > + } > break; > case SYS_ID_AA64ISAR1_EL1: > if (!vcpu_has_ptrauth(vcpu)) > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 79d9c44d1ad7..d4da58ddcad7 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1083,6 +1083,7 @@ struct kvm_ppc_resize_hpt { > #define KVM_CAP_SGX_ATTRIBUTE 196 > #define KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 197 > #define KVM_CAP_PTP_KVM 198 > +#define KVM_CAP_ARM_MTE 199 > > #ifdef KVM_CAP_IRQ_ROUTING > > -- > 2.20.1 > > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
On Mon, 21 Jun 2021 18:00:20 +0100, Fuad Tabba <tabba@google.com> wrote: > > Hi, > > On Mon, Jun 21, 2021 at 12:18 PM Steven Price <steven.price@arm.com> wrote: > > > > Add a new VM feature 'KVM_ARM_CAP_MTE' which enables memory tagging > > for a VM. This will expose the feature to the guest and automatically > > tag memory pages touched by the VM as PG_mte_tagged (and clear the tag > > storage) to ensure that the guest cannot see stale tags, and so that > > the tags are correctly saved/restored across swap. > > > > Actually exposing the new capability to user space happens in a later > > patch. > > > > Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> > > Signed-off-by: Steven Price <steven.price@arm.com> > > --- > > arch/arm64/include/asm/kvm_emulate.h | 3 ++ > > arch/arm64/include/asm/kvm_host.h | 3 ++ > > arch/arm64/kvm/hyp/exception.c | 3 +- > > arch/arm64/kvm/mmu.c | 64 +++++++++++++++++++++++++++- > > arch/arm64/kvm/sys_regs.c | 7 +++ > > include/uapi/linux/kvm.h | 1 + > > 6 files changed, 79 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h > > index 01b9857757f2..fd418955e31e 100644 > > --- a/arch/arm64/include/asm/kvm_emulate.h > > +++ b/arch/arm64/include/asm/kvm_emulate.h > > @@ -84,6 +84,9 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) > > if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) || > > vcpu_el1_is_32bit(vcpu)) > > vcpu->arch.hcr_el2 |= HCR_TID2; > > + > > + if (kvm_has_mte(vcpu->kvm)) > > + vcpu->arch.hcr_el2 |= HCR_ATA; > > } > > > > static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > > index 7cd7d5c8c4bc..afaa5333f0e4 100644 > > --- a/arch/arm64/include/asm/kvm_host.h > > +++ b/arch/arm64/include/asm/kvm_host.h > > @@ -132,6 +132,8 @@ struct kvm_arch { > > > > u8 pfr0_csv2; > > u8 pfr0_csv3; > > + /* Memory Tagging Extension enabled for the guest */ > > + bool mte_enabled; > > }; > > nit: newline before the comment/new member > > > > > struct kvm_vcpu_fault_info { > > @@ -769,6 +771,7 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); > > #define kvm_arm_vcpu_sve_finalized(vcpu) \ > > ((vcpu)->arch.flags & KVM_ARM64_VCPU_SVE_FINALIZED) > > > > +#define kvm_has_mte(kvm) (system_supports_mte() && (kvm)->arch.mte_enabled) > > #define kvm_vcpu_has_pmu(vcpu) \ > > (test_bit(KVM_ARM_VCPU_PMU_V3, (vcpu)->arch.features)) > > > > diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c > > index 11541b94b328..0418399e0a20 100644 > > --- a/arch/arm64/kvm/hyp/exception.c > > +++ b/arch/arm64/kvm/hyp/exception.c > > @@ -112,7 +112,8 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, > > new |= (old & PSR_C_BIT); > > new |= (old & PSR_V_BIT); > > > > - // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests) > > + if (kvm_has_mte(vcpu->kvm)) > > + new |= PSR_TCO_BIT; > > > > new |= (old & PSR_DIT_BIT); > > > > diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c > > index c10207fed2f3..52326b739357 100644 > > --- a/arch/arm64/kvm/mmu.c > > +++ b/arch/arm64/kvm/mmu.c > > @@ -822,6 +822,45 @@ transparent_hugepage_adjust(struct kvm_memory_slot *memslot, > > return PAGE_SIZE; > > } > > > > +/* > > + * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be > > + * able to see the page's tags and therefore they must be initialised first. If > > + * PG_mte_tagged is set, tags have already been initialised. > > + * > > + * The race in the test/set of the PG_mte_tagged flag is handled by: > > + * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs > > + * racing to santise the same page > > + * - mmap_lock protects between a VM faulting a page in and the VMM performing > > + * an mprotect() to add VM_MTE > > + */ > > +static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, > > + unsigned long size) > > +{ > > + unsigned long i, nr_pages = size >> PAGE_SHIFT; > > + struct page *page; > > + > > + if (!kvm_has_mte(kvm)) > > + return 0; > > + > > + /* > > + * pfn_to_online_page() is used to reject ZONE_DEVICE pages > > + * that may not support tags. > > + */ > > + page = pfn_to_online_page(pfn); > > + > > + if (!page) > > + return -EFAULT; > > + > > + for (i = 0; i < nr_pages; i++, page++) { > > + if (!test_bit(PG_mte_tagged, &page->flags)) { > > + mte_clear_page_tags(page_address(page)); > > + set_bit(PG_mte_tagged, &page->flags); > > + } > > + } > > + > > + return 0; > > +} > > + > > static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > > struct kvm_memory_slot *memslot, unsigned long hva, > > unsigned long fault_status) > > @@ -971,8 +1010,18 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, > > if (writable) > > prot |= KVM_PGTABLE_PROT_W; > > > > - if (fault_status != FSC_PERM && !device) > > + if (fault_status != FSC_PERM && !device) { > > + /* Check the VMM hasn't introduced a new VM_SHARED VMA */ > > + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) { > > + ret = -EFAULT; > > + goto out_unlock; > > + } > > + ret = sanitise_mte_tags(kvm, pfn, vma_pagesize); > > + if (ret) > > + goto out_unlock; > > + > > nit: Would it make sense to bring in sanitise_mte_tags under the > kvm_has_mte. I know that a check is done in kvm_has_mte as well, but > since you're already checking, it might make the code a bit clearer. I think it makes more sense once merged with -next, as the CMO has been moved into the PT code. I came up with the following resolution: if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) vma_pagesize = transparent_hugepage_adjust(memslot, hva, &pfn, &fault_ipa); if (fault_status != FSC_PERM && !device && kvm_has_mte(kvm)) { /* Check the VMM hasn't introduced a new VM_SHARED VMA */ if (!(vma->vm_flags & VM_SHARED)) ret = sanitise_mte_tags(kvm, pfn, vma_pagesize); else ret = -EFAULT; if (ret) goto out_unlock; } if (writable) prot |= KVM_PGTABLE_PROT_W; However, there is a more annoying issue here, which is that the vma is accessed outside of the mm lock. I *think* we're safe because if an unmap happens in parallel, the MMU notifier will kick and we will be in one of two cases: - the unmap occurs before we take the kvm->mmu_lock, and the mmu notifier seq_lock is want saves us (we will drop everything and take the fault again), - it occurs once we hold the lock, and this blocks the unmap. Either way, I'd be more confident if the shared state was sampled inside the locked section. Thoughts? M.
diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 01b9857757f2..fd418955e31e 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -84,6 +84,9 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) || vcpu_el1_is_32bit(vcpu)) vcpu->arch.hcr_el2 |= HCR_TID2; + + if (kvm_has_mte(vcpu->kvm)) + vcpu->arch.hcr_el2 |= HCR_ATA; } static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 7cd7d5c8c4bc..afaa5333f0e4 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -132,6 +132,8 @@ struct kvm_arch { u8 pfr0_csv2; u8 pfr0_csv3; + /* Memory Tagging Extension enabled for the guest */ + bool mte_enabled; }; struct kvm_vcpu_fault_info { @@ -769,6 +771,7 @@ bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu); #define kvm_arm_vcpu_sve_finalized(vcpu) \ ((vcpu)->arch.flags & KVM_ARM64_VCPU_SVE_FINALIZED) +#define kvm_has_mte(kvm) (system_supports_mte() && (kvm)->arch.mte_enabled) #define kvm_vcpu_has_pmu(vcpu) \ (test_bit(KVM_ARM_VCPU_PMU_V3, (vcpu)->arch.features)) diff --git a/arch/arm64/kvm/hyp/exception.c b/arch/arm64/kvm/hyp/exception.c index 11541b94b328..0418399e0a20 100644 --- a/arch/arm64/kvm/hyp/exception.c +++ b/arch/arm64/kvm/hyp/exception.c @@ -112,7 +112,8 @@ static void enter_exception64(struct kvm_vcpu *vcpu, unsigned long target_mode, new |= (old & PSR_C_BIT); new |= (old & PSR_V_BIT); - // TODO: TCO (if/when ARMv8.5-MemTag is exposed to guests) + if (kvm_has_mte(vcpu->kvm)) + new |= PSR_TCO_BIT; new |= (old & PSR_DIT_BIT); diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index c10207fed2f3..52326b739357 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -822,6 +822,45 @@ transparent_hugepage_adjust(struct kvm_memory_slot *memslot, return PAGE_SIZE; } +/* + * The page will be mapped in stage 2 as Normal Cacheable, so the VM will be + * able to see the page's tags and therefore they must be initialised first. If + * PG_mte_tagged is set, tags have already been initialised. + * + * The race in the test/set of the PG_mte_tagged flag is handled by: + * - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs + * racing to santise the same page + * - mmap_lock protects between a VM faulting a page in and the VMM performing + * an mprotect() to add VM_MTE + */ +static int sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn, + unsigned long size) +{ + unsigned long i, nr_pages = size >> PAGE_SHIFT; + struct page *page; + + if (!kvm_has_mte(kvm)) + return 0; + + /* + * pfn_to_online_page() is used to reject ZONE_DEVICE pages + * that may not support tags. + */ + page = pfn_to_online_page(pfn); + + if (!page) + return -EFAULT; + + for (i = 0; i < nr_pages; i++, page++) { + if (!test_bit(PG_mte_tagged, &page->flags)) { + mte_clear_page_tags(page_address(page)); + set_bit(PG_mte_tagged, &page->flags); + } + } + + return 0; +} + static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, struct kvm_memory_slot *memslot, unsigned long hva, unsigned long fault_status) @@ -971,8 +1010,18 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (writable) prot |= KVM_PGTABLE_PROT_W; - if (fault_status != FSC_PERM && !device) + if (fault_status != FSC_PERM && !device) { + /* Check the VMM hasn't introduced a new VM_SHARED VMA */ + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) { + ret = -EFAULT; + goto out_unlock; + } + ret = sanitise_mte_tags(kvm, pfn, vma_pagesize); + if (ret) + goto out_unlock; + clean_dcache_guest_page(pfn, vma_pagesize); + } if (exec_fault) { prot |= KVM_PGTABLE_PROT_X; @@ -1168,12 +1217,17 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range) bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) { kvm_pfn_t pfn = pte_pfn(range->pte); + int ret; if (!kvm->arch.mmu.pgt) return false; WARN_ON(range->end - range->start != 1); + ret = sanitise_mte_tags(kvm, pfn, PAGE_SIZE); + if (ret) + return false; + /* * We've moved a page around, probably through CoW, so let's treat it * just like a translation fault and clean the cache to the PoC. @@ -1381,6 +1435,14 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, if (!vma) break; + /* + * VM_SHARED mappings are not allowed with MTE to avoid races + * when updating the PG_mte_tagged page flag, see + * sanitise_mte_tags for more details. + */ + if (kvm_has_mte(kvm) && vma->vm_flags & VM_SHARED) + return -EINVAL; + /* * Take the intersection of this VMA with the memory region */ diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 1a7968ad078c..36f67f8deae1 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1047,6 +1047,13 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, break; case SYS_ID_AA64PFR1_EL1: val &= ~FEATURE(ID_AA64PFR1_MTE); + if (kvm_has_mte(vcpu->kvm)) { + u64 pfr, mte; + + pfr = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1); + mte = cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR1_MTE_SHIFT); + val |= FIELD_PREP(FEATURE(ID_AA64PFR1_MTE), mte); + } break; case SYS_ID_AA64ISAR1_EL1: if (!vcpu_has_ptrauth(vcpu)) diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 79d9c44d1ad7..d4da58ddcad7 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1083,6 +1083,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_SGX_ATTRIBUTE 196 #define KVM_CAP_VM_COPY_ENC_CONTEXT_FROM 197 #define KVM_CAP_PTP_KVM 198 +#define KVM_CAP_ARM_MTE 199 #ifdef KVM_CAP_IRQ_ROUTING