Thread (17 messages) 17 messages, 3 authors, 2021-09-22

Re: [PATCH v5 3/8] KVM: arm64: Simplify masking out MTE in feature id reg

From: Andrew Jones <hidden>
Date: 2021-09-08 12:40:54
Also in: kvm, kvmarm

On Fri, Aug 27, 2021 at 11:16:04AM +0100, Fuad Tabba wrote:
quoted hunk ↗ jump to hunk
Simplify code for hiding MTE support in feature id register when
MTE is not enabled/supported by KVM.

No functional change intended.

Signed-off-by: Fuad Tabba <redacted>
---
 arch/arm64/kvm/sys_regs.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 1d46e185f31e..447acce9ca84 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1077,14 +1077,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 		val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_CSV3), (u64)vcpu->kvm->arch.pfr0_csv3);
 		break;
 	case SYS_ID_AA64PFR1_EL1:
-		val &= ~ARM64_FEATURE_MASK(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(ARM64_FEATURE_MASK(ID_AA64PFR1_MTE), mte);
-		}
+		if (!kvm_has_mte(vcpu->kvm))
+			val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE);
 		break;
 	case SYS_ID_AA64ISAR1_EL1:
 		if (!vcpu_has_ptrauth(vcpu))
-- 
2.33.0.259.gc128427fd7-goog
Reviewed-by: Andrew Jones <redacted>


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