[PATCH v3 11/28] KVM: arm64: Expose FEAT_NV2p1 to NV guests
From: Marc Zyngier <maz@kernel.org>
Date: 2026-07-22 07:42:58
Also in:
kvm, kvmarm
Subsystem:
arm64 port (aarch64 architecture), kernel virtual machine for arm64 (kvm/arm64), the rest · Maintainers:
Catalin Marinas, Will Deacon, Marc Zyngier, Oliver Upton, Linus Torvalds
Since NV2p1 is reducing the number of traps, it is valuable to expose it to NV guests. Do so. Signed-off-by: Marc Zyngier <maz@kernel.org> --- arch/arm64/kvm/nested.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index dfb96edbdc43c..35a1c42ad3f84 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c@@ -1728,7 +1728,7 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) * You get EITHER * * - FEAT_VHE without FEAT_E2H0 - * - FEAT_NV limited to FEAT_NV2 + * - FEAT_NV limited to FEAT_NV2(p1) * - HCR_EL2.NV1 being RES0 * * OR
@@ -1740,7 +1740,11 @@ u64 limit_nv_id_reg(struct kvm *kvm, u32 reg, u64 val) if (test_bit(KVM_ARM_VCPU_HAS_EL2_E2H0, kvm->arch.vcpu_features)) { val = 0; } else { - val = SYS_FIELD_PREP_ENUM(ID_AA64MMFR4_EL1, NV_frac, NV2_ONLY); + val &= ID_AA64MMFR4_EL1_NV_frac; + if (cpus_have_final_cap(ARM64_HAS_NV2P1)) + val = ID_REG_LIMIT_FIELD_ENUM(val, ID_AA64MMFR4_EL1, NV_frac, NV2P1); + else + val = SYS_FIELD_PREP_ENUM(ID_AA64MMFR4_EL1, NV_frac, NV2_ONLY); val |= SYS_FIELD_PREP_ENUM(ID_AA64MMFR4_EL1, E2H0, NI_NV1); } break;
--
2.47.3