2 files changed, 15 insertions, 0 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index db5021b2b5a8..1c4a018bf4bb 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -417,6 +417,9 @@ static __init int svm_hardware_setup(void)
         if (boot_cpu_has(X86_FEATURE_NX))
                 kvm_enable_efer_bits(EFER_NX);
 
+        if (boot_cpu_has(X86_FEATURE_FXSR_OPT))
+                kvm_enable_efer_bits(EFER_FFXSR);
+
         if (nested) {
                 printk(KERN_INFO "kvm: Nested Virtualization enabled\n");
                 kvm_enable_efer_bits(EFER_SVME);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 32e3a7ec6ad2..8f83590b47dd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -490,6 +490,17 @@ static void set_efer(struct kvm_vcpu *vcpu, u64 efer)
                 return;
         }
 
+        if (efer & EFER_FFXSR) {
+                struct kvm_cpuid_entry2 *feat;
+
+                feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+                if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT))) {
+                        printk(KERN_DEBUG "set_efer: #GP, enable FFXSR w/o CPUID capability\n");
+                        kvm_inject_gp(vcpu, 0);
+                        return;
+                }
+        }
+
         if (efer & EFER_SVME) {
                 struct kvm_cpuid_entry2 *feat;
 
@@ -1240,6 +1251,7 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 #ifdef CONFIG_X86_64
                 bit(X86_FEATURE_LM) |
 #endif
+                bit(X86_FEATURE_FXSR_OPT) |
                 bit(X86_FEATURE_MMXEXT) |
                 bit(X86_FEATURE_3DNOWEXT) |
                 bit(X86_FEATURE_3DNOW);