From 8f8d6084f5b5df7e29b58ff17b6c735fb349b1a9 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 20 Feb 2025 13:48:57 +0000 Subject: [PATCH] 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: Marc Zyngier Reviewed-by: Joey Gouly Link: https://lore.kernel.org/r/20250220134907.554085-5-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/nested.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index ed3add7d32f66..9f140560a6f5d 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -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); -- 2.39.5