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authorSteven Price <steven.price@arm.com>2021-06-21 12:17:12 +0100
committerMarc Zyngier <maz@kernel.org>2021-06-22 14:08:05 +0100
commitea7fc1bb1cd1b92b42b1d9273ce7e231d3dc9321 (patch)
tree69524ca0a8e1c7048db4490cb5b73ad65266f2c5 /arch/arm64/kvm/sys_regs.c
parent69e3b846d8a753f9f279f29531ca56b0f7563ad0 (diff)
downloadlwn-ea7fc1bb1cd1b92b42b1d9273ce7e231d3dc9321.tar.gz
lwn-ea7fc1bb1cd1b92b42b1d9273ce7e231d3dc9321.zip
KVM: arm64: Introduce MTE VM feature
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> [maz: move VM_SHARED sampling into the critical section] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20210621111716.37157-3-steven.price@arm.com
Diffstat (limited to 'arch/arm64/kvm/sys_regs.c')
-rw-r--r--arch/arm64/kvm/sys_regs.c7
1 files changed, 7 insertions, 0 deletions
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))