[PATCH 2/3] Add RDWRGSFS support when setting CR4

["Yang, Wei" <wei.y.yang@intel.com>]

This patch adds RDWRGSFS support when setting CR4.

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

---
 arch/x86/kvm/x86.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ff4623b..59d25ce 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;
-- 
1.7.1