KVM: x86 emulator: re-implementing 'mov AL,moffs' instruction decoding

This patch change to use DstAcc for decoding 'mov AL, moffs'
and introduced SrcAcc for decoding 'mov moffs, AL'.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 23 insertions, 9 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 286572a5675b..255473f974ab 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -70,6 +70,7 @@
 #define SrcSI       (0xa<<4)    /* Source is in the DS:RSI */
 #define SrcImmFAddr (0xb<<4)    /* Source is immediate far address */
 #define SrcMemFAddr (0xc<<4)    /* Source is far address in memory */
+#define SrcAcc      (0xd<<4)    /* Source Accumulator */
 #define SrcMask     (0xf<<4)
 /* Generic ModRM decode. */
 #define ModRM       (1<<8)
@@ -177,8 +178,8 @@ static u32 opcode_table[256] = {
         0, 0, SrcImmFAddr | No64, 0,
         ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
         /* 0xA0 - 0xA7 */
-        ByteOp | DstReg | SrcMem | Mov | MemAbs, DstReg | SrcMem | Mov | MemAbs,
-        ByteOp | DstMem | SrcReg | Mov | MemAbs, DstMem | SrcReg | Mov | MemAbs,
+        ByteOp | DstAcc | SrcMem | Mov | MemAbs, DstAcc | SrcMem | Mov | MemAbs,
+        ByteOp | DstMem | SrcAcc | Mov | MemAbs, DstMem | SrcAcc | Mov | MemAbs,
         ByteOp | SrcSI | DstDI | Mov | String, SrcSI | DstDI | Mov | String,
         ByteOp | SrcSI | DstDI | String, SrcSI | DstDI | String,
         /* 0xA8 - 0xAF */
@@ -1186,6 +1187,25 @@ done_prefixes:
                 else
                         c->src.val = insn_fetch(u8, 1, c->eip);
                 break;
+        case SrcAcc:
+                c->src.type = OP_REG;
+                c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+                c->src.ptr = &c->regs[VCPU_REGS_RAX];
+                switch (c->src.bytes) {
+                        case 1:
+                                c->src.val = *(u8 *)c->src.ptr;
+                                break;
+                        case 2:
+                                c->src.val = *(u16 *)c->src.ptr;
+                                break;
+                        case 4:
+                                c->src.val = *(u32 *)c->src.ptr;
+                                break;
+                        case 8:
+                                c->src.val = *(u64 *)c->src.ptr;
+                                break;
+                }
+                break;
         case SrcOne:
                 c->src.bytes = 1;
                 c->src.val = 1;
@@ -2854,13 +2874,7 @@ special_insn:
                 if (rc != X86EMUL_CONTINUE)
                         goto done;
                 break;
-        case 0xa0 ... 0xa1:     /* mov */
-                c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
-                c->dst.val = c->src.val;
-                break;
-        case 0xa2 ... 0xa3:     /* mov */
-                c->dst.val = (unsigned long)c->regs[VCPU_REGS_RAX];
-                break;
+        case 0xa0 ... 0xa3:     /* mov */
         case 0xa4 ... 0xa5:     /* movs */
                 goto mov;
         case 0xa6 ... 0xa7:     /* cmps */