From 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5 Mon Sep 17 00:00:00 2001 From: Fuad Tabba Date: Tue, 25 Aug 2026 09:59:48 +0100 Subject: [PATCH] KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2 pkvm_init_features_from_host() takes KVM_ARCH_FLAG_GUEST_HAS_SVE and KVM_ARM_VCPU_SVE from the host separately, but pkvm_vcpu_init_sve() tests the bit while vcpu_has_sve() reads the flag. A host that sets the flag without the bit gets a vCPU with a NULL sve_state that the world switch loads the guest's SVE state from. Derive the flag from the bit, and drop the protected path's copy of the host's flag, which is dead code since protected VMs are not allowed SVE. Fixes: 41d6028e28bd ("KVM: arm64: Convert the SVE guest vcpu flag to a vm flag") Signed-off-by: Fuad Tabba Link: https://patch.msgid.link/20260825085948.1674721-5-fuad.tabba@linux.dev Signed-off-by: Oliver Upton --- arch/arm64/kvm/hyp/nvhe/pkvm.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c index 453d3fa4a420..bb3e0dc0676e 100644 --- a/arch/arm64/kvm/hyp/nvhe/pkvm.c +++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c @@ -360,7 +360,7 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc if (test_bit(KVM_ARCH_FLAG_WRITABLE_IMP_ID_REGS, &host_arch_flags)) hyp_vm->kvm.arch.midr_el1 = host_kvm->arch.midr_el1; - return; + goto out; } if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_MTE)) @@ -379,13 +379,14 @@ static void pkvm_init_features_from_host(struct pkvm_hyp_vm *hyp_vm, const struc if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC)) set_bit(KVM_ARM_VCPU_PTRAUTH_GENERIC, allowed_features); - if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) { + if (kvm_pkvm_ext_allowed(kvm, KVM_CAP_ARM_SVE)) set_bit(KVM_ARM_VCPU_SVE, allowed_features); - kvm->arch.flags |= host_arch_flags & BIT(KVM_ARCH_FLAG_GUEST_HAS_SVE); - } bitmap_and(kvm->arch.vcpu_features, host_kvm->arch.vcpu_features, allowed_features, KVM_VCPU_MAX_FEATURES); +out: + __assign_bit(KVM_ARCH_FLAG_GUEST_HAS_SVE, &kvm->arch.flags, + kvm_vcpu_has_feature(kvm, KVM_ARM_VCPU_SVE)); } static void unpin_host_vcpu(struct kvm_vcpu *host_vcpu)