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/emulate.c

@@ -3514,6 +3514,16 @@ static int em_cwd(struct x86_emulate_ctxt *ctxt)
 	return X86EMUL_CONTINUE;
 }
 
+static int em_rdpid(struct x86_emulate_ctxt *ctxt)
+{
+	u64 tsc_aux = 0;
+
+	if (ctxt->ops->get_msr(ctxt, MSR_TSC_AUX, &tsc_aux))
+		return emulate_gp(ctxt, 0);
+	ctxt->dst.val = tsc_aux;
+	return X86EMUL_CONTINUE;
+}
+
 static int em_rdtsc(struct x86_emulate_ctxt *ctxt)
 {
 	u64 tsc = 0;
@@ -4424,10 +4434,20 @@ static const struct opcode group8[] = {
 	F(DstMem | SrcImmByte | Lock | PageTable,	em_btc),
 };
 
+/*
+ * The "memory" destination is actually always a register, since we come
+ * from the register case of group9.
+ */
+static const struct gprefix pfx_0f_c7_7 = {
+	N, N, N, II(DstMem | ModRM | Op3264 | EmulateOnUD, em_rdpid, rdtscp),
+};
+
+
 static const struct group_dual group9 = { {
 	N, I(DstMem64 | Lock | PageTable, em_cmpxchg8b), N, N, N, N, N, N,
 }, {
-	N, N, N, N, N, N, N, N,
+	N, N, N, N, N, N, N,
+	GP(0, &pfx_0f_c7_7),
 } };
 
 static const struct opcode group11[] = {