KVM: x86 emulator: add Src2Imm decoding

Needed for 3-operand IMUL.
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/kvm/emulate.c

@@ -95,6 +95,7 @@
 #define Src2CL      (1<<29)
 #define Src2ImmByte (2<<29)
 #define Src2One     (3<<29)
+#define Src2Imm     (4<<29)
 #define Src2Mask    (7<<29)
 
 #define X2(x...) x, x
@@ -2844,6 +2845,9 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt)
 		c->src2.bytes = 1;
 		c->src2.val = 1;
 		break;
+	case Src2Imm:
+		rc = decode_imm(ctxt, &c->src2, imm_size(c), true);
+		break;
 	}
 
 	if (rc != X86EMUL_CONTINUE)