From 96be4e069c938e4a5fc7125de7e1cc7089b1adef Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 10 Dec 2019 14:44:15 -0800 Subject: [PATCH] KVM: x86: Drop special XSAVE handling from guest_cpuid_has() Now that KVM prevents setting host-reserved CR4 bits, drop the dedicated XSAVE check in guest_cpuid_has() in favor of open coding similar checks in the SVM/VMX XSAVES enabling flows. Note, checking boot_cpu_has(X86_FEATURE_XSAVE) in the XSAVES flows is technically redundant with respect to the CR4 reserved bit checks, e.g. XSAVES #UDs if CR4.OSXSAVE=0 and arch.xsaves_enabled is consumed if and only if CR4.OXSAVE=1 in guest. Keep (add?) the explicit boot_cpu_has() checks to help document KVM's usage of arch.xsaves_enabled. No functional change intended. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/cpuid.h | 4 ---- arch/x86/kvm/svm.c | 1 + arch/x86/kvm/vmx/vmx.c | 1 + 3 files changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h index d78a61408243..b82ae4d3dc71 100644 --- a/arch/x86/kvm/cpuid.h +++ b/arch/x86/kvm/cpuid.h @@ -93,10 +93,6 @@ static __always_inline bool guest_cpuid_has(struct kvm_vcpu *vcpu, unsigned x86_ { int *reg; - if (x86_feature == X86_FEATURE_XSAVE && - !static_cpu_has(X86_FEATURE_XSAVE)) - return false; - reg = guest_cpuid_get_register(vcpu, x86_feature); if (!reg) return false; diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 9583ae7ae218..d399eb7bbff3 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5917,6 +5917,7 @@ static void svm_cpuid_update(struct kvm_vcpu *vcpu) struct vcpu_svm *svm = to_svm(vcpu); vcpu->arch.xsaves_enabled = guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && + boot_cpu_has(X86_FEATURE_XSAVE) && boot_cpu_has(X86_FEATURE_XSAVES); /* Update nrips enabled cache */ diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 857dd0898e5f..3e732d092c40 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -4049,6 +4049,7 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx) if (vmx_xsaves_supported()) { /* Exposing XSAVES only when XSAVE is exposed */ bool xsaves_enabled = + boot_cpu_has(X86_FEATURE_XSAVE) && guest_cpuid_has(vcpu, X86_FEATURE_XSAVE) && guest_cpuid_has(vcpu, X86_FEATURE_XSAVES); -- 2.39.5