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KVM: arm64: Mark HCR.EL2.{NV*,AT} RES0 when ID_AA64MMFR4_EL1.NV_frac is 0

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Enforce HCR_EL2.{NV*,AT} being RES0 when NV2 is disabled, so that
we can actually rely on these bits never being flipped behind our back.

This of course relies on our earlier ID reg sanitising.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-5-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Marc Zyngier
2025-02-20 13:48:57 +00:00
committed by Oliver Upton
parent d9f943f765
commit 8f8d6084f5
1 changed files with 5 additions and 4 deletions
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arch/arm64/kvm/nested.c
+5 -4
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@@ -1021,10 +1021,11 @@ int kvm_init_nv_sysregs(struct kvm_vcpu *vcpu)
res0 |= HCR_FIEN;
if (!kvm_has_feat(kvm, ID_AA64MMFR2_EL1, FWB, IMP))
res0 |= HCR_FWB;
if (!kvm_has_feat(kvm, ID_AA64MMFR2_EL1, NV, NV2))
res0 |= HCR_NV2;
if (!kvm_has_feat(kvm, ID_AA64MMFR2_EL1, NV, IMP))
res0 |= (HCR_AT | HCR_NV1 | HCR_NV);
/* Implementation choice: NV2 is the only supported config */
if (!kvm_has_feat(kvm, ID_AA64MMFR4_EL1, NV_frac, NV2_ONLY))
res0 |= (HCR_NV2 | HCR_NV | HCR_AT);
if (!kvm_has_feat(kvm, ID_AA64MMFR4_EL1, E2H0, NI))
res0 |= HCR_NV1;
if (!(kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_PTRAUTH_ADDRESS) &&
kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_PTRAUTH_GENERIC)))
res0 |= (HCR_API | HCR_APK);