KVM: x86 emulator: Add decoding of 16bit second in memory argument

Add decoding of Ep type of argument used by callf/jmpf.
Signed-off-by: NGleb Natapov <gleb@redhat.com>
Signed-off-by: NAvi Kivity <avi@redhat.com>

arch/x86/kvm/emulate.c

@@ -85,6 +85,9 @@
 #define Src2ImmByte (2<<29)
 #define Src2One     (3<<29)
 #define Src2Imm16   (4<<29)
+#define Src2Mem16   (5<<29) /* Used for Ep encoding. First argument has to be
+			       in memory and second argument is located
+			       immediately after the first one in memory. */
 #define Src2Mask    (7<<29)
 
 enum {
@@ -1163,6 +1166,10 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		c->src2.bytes = 1;
 		c->src2.val = 1;
 		break;
+	case Src2Mem16:
+		c->src2.bytes = 2;
+		c->src2.type = OP_MEM;
+		break;
 	}
 
 	/* Decode and fetch the destination operand: register or memory. */
@@ -1881,6 +1888,17 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
 		c->src.orig_val = c->src.val;
 	}
 
+	if (c->src2.type == OP_MEM) {
+		c->src2.ptr = (unsigned long *)(memop + c->src.bytes);
+		c->src2.val = 0;
+		rc = ops->read_emulated((unsigned long)c->src2.ptr,
+					&c->src2.val,
+					c->src2.bytes,
+					ctxt->vcpu);
+		if (rc != X86EMUL_CONTINUE)
+			goto done;
+	}
+
 	if ((c->d & DstMask) == ImplicitOps)
 		goto special_insn;