Commit 8f8d6084 authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
Browse files

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



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: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250220134907.554085-5-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent d9f943f7

arch/arm64/kvm/nested.c

+5 −4
Original line number Diff line number Diff line
@@ -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);