KVM: x86: Make CR4.VMXE reserved for the guest

CR4.VMXE is reserved unless the VMX CPUID bit is set.  On Intel,
it is also tested by vmx_set_cr4, but AMD relies on kvm_valid_cr4,
so fix it.
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.h

@@ -391,6 +391,8 @@ bool kvm_vcpu_exit_request(struct kvm_vcpu *vcpu);
 		__reserved_bits |= X86_CR4_LA57;        \
 	if (!__cpu_has(__c, X86_FEATURE_UMIP))          \
 		__reserved_bits |= X86_CR4_UMIP;        \
+	if (!__cpu_has(__c, X86_FEATURE_VMX))           \
+		__reserved_bits |= X86_CR4_VMXE;        \
 	__reserved_bits;                                \
 })