KVM: x86: emulate RDPID

This is encoded as F3 0F C7 /7 with a register argument.  The register
argument is the second array in the group9 GroupDual, while F3 is the
fourth element of a Prefix.

Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/cpuid.c

@@ -293,13 +293,18 @@ static int __do_cpuid_ent_emulated(struct kvm_cpuid_entry2 *entry,
 {
 	switch (func) {
 	case 0:
-		entry->eax = 1;		/* only one leaf currently */
+		entry->eax = 7;
 		++*nent;
 		break;
 	case 1:
 		entry->ecx = F(MOVBE);
 		++*nent;
 		break;
+	case 7:
+		entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX;
+		if (index == 0)
+			entry->ecx = F(RDPID);
+		++*nent;
 	default:
 		break;
 	}