From 4eb87460c4740030086411c3b7a7e167fb7e57bd Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 2 Mar 2020 15:57:08 -0800 Subject: [PATCH] KVM: nSVM: Advertise and enable NRIPS for L1 iff nrips is enabled Set NRIPS in KVM capabilities if and only if nrips=true, which naturally incorporates the boot_cpu_has() check, and set nrips_enabled only if the KVM capability is enabled. Note, previously KVM would set nrips_enabled based purely on userspace input, but at worst that would cause KVM to propagate garbage into L1, i.e. userspace would simply be hosing its VM. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 76a480a..9b173d5 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -1375,7 +1375,7 @@ static __init void svm_set_cpu_caps(void) if (nested) { kvm_cpu_cap_set(X86_FEATURE_SVM); - if (boot_cpu_has(X86_FEATURE_NRIPS)) + if (nrips) kvm_cpu_cap_set(X86_FEATURE_NRIPS); if (npt_enabled) @@ -6029,7 +6029,8 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu) boot_cpu_has(X86_FEATURE_XSAVES); /* Update nrips enabled cache */ - svm->nrips_enabled = !!guest_cpuid_has(&svm->vcpu, X86_FEATURE_NRIPS); + svm->nrips_enabled = kvm_cpu_cap_has(X86_FEATURE_NRIPS) && + guest_cpuid_has(&svm->vcpu, X86_FEATURE_NRIPS); if (!kvm_vcpu_apicv_active(vcpu)) return; -- 2.7.4