KVM: x86: Mark bit 7 in long-mode PDPTE according to 1GB pages support

In long-mode, bit 7 in the PDPTE is not reserved only if 1GB pages are
supported by the CPU. Currently the bit is considered by KVM as always
reserved.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h
index eeecbed..f908731 100644
--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -88,4 +88,11 @@
 	return best && (best->ecx & bit(X86_FEATURE_X2APIC));
 }
 
+static inline bool guest_cpuid_has_gbpages(struct kvm_vcpu *vcpu)
+{
+	struct kvm_cpuid_entry2 *best;
+
+	best = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
+	return best && (best->edx & bit(X86_FEATURE_GBPAGES));
+}
 #endif