KVM: Add RDWRGSFS support when setting CR4

This patch adds RDWRGSFS support when setting CR4.

Signed-off-by: Yang, Wei <wei.y.yang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6f1e54d0828d..423e0cda8e91 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -588,6 +588,14 @@ static bool guest_cpuid_has_smep(struct kvm_vcpu *vcpu)
         return best && (best->ebx & bit(X86_FEATURE_SMEP));
 }
 
+static bool guest_cpuid_has_fsgsbase(struct kvm_vcpu *vcpu)
+{
+        struct kvm_cpuid_entry2 *best;
+
+        best = kvm_find_cpuid_entry(vcpu, 7, 0);
+        return best && (best->ebx & bit(X86_FEATURE_FSGSBASE));
+}
+
 static void update_cpuid(struct kvm_vcpu *vcpu)
 {
         struct kvm_cpuid_entry2 *best;
@@ -618,6 +626,9 @@ int kvm_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
         if (!guest_cpuid_has_smep(vcpu) && (cr4 & X86_CR4_SMEP))
                 return 1;
 
+        if (!guest_cpuid_has_fsgsbase(vcpu) && (cr4 & X86_CR4_RDWRGSFS))
+                return 1;
+
         if (is_long_mode(vcpu)) {
                 if (!(cr4 & X86_CR4_PAE))
                         return 1;