]> pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - arch/x86/kvm/x86_emulate.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
[linux-2.6-omap-h63xx.git] / arch / x86 / kvm / x86_emulate.c
index 79586003397aa7c90bc171f020710ce1fa2054e0..2ca08386f9937ea43c4d126ca011af96c10abde9 100644 (file)
 #define MemAbs      (1<<9)      /* Memory operand is absolute displacement */
 #define String      (1<<10)     /* String instruction (rep capable) */
 #define Stack       (1<<11)     /* Stack instruction (push/pop) */
+#define Group       (1<<14)     /* Bits 3:5 of modrm byte extend opcode */
+#define GroupDual   (1<<15)     /* Alternate decoding of mod == 3 */
+#define GroupMask   0xff        /* Group number stored in bits 0:7 */
+
+enum {
+       Group1_80, Group1_81, Group1_82, Group1_83,
+       Group1A, Group3_Byte, Group3, Group4, Group5, Group7,
+};
 
 static u16 opcode_table[256] = {
        /* 0x00 - 0x07 */
@@ -123,14 +131,14 @@ static u16 opcode_table[256] = {
        ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
        ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
        /* 0x80 - 0x87 */
-       ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
-       ByteOp | DstMem | SrcImm | ModRM, DstMem | SrcImmByte | ModRM,
+       Group | Group1_80, Group | Group1_81,
+       Group | Group1_82, Group | Group1_83,
        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
        ByteOp | DstMem | SrcReg | ModRM, DstMem | SrcReg | ModRM,
        /* 0x88 - 0x8F */
        ByteOp | DstMem | SrcReg | ModRM | Mov, DstMem | SrcReg | ModRM | Mov,
        ByteOp | DstReg | SrcMem | ModRM | Mov, DstReg | SrcMem | ModRM | Mov,
-       0, ModRM | DstReg, 0, DstMem | SrcNone | ModRM | Mov | Stack,
+       0, ModRM | DstReg, 0, Group | Group1A,
        /* 0x90 - 0x9F */
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, ImplicitOps | Stack, ImplicitOps | Stack, 0, 0,
@@ -164,16 +172,15 @@ static u16 opcode_table[256] = {
        0, 0, 0, 0,
        /* 0xF0 - 0xF7 */
        0, 0, 0, 0,
-       ImplicitOps, ImplicitOps,
-       ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM,
+       ImplicitOps, ImplicitOps, Group | Group3_Byte, Group | Group3,
        /* 0xF8 - 0xFF */
        ImplicitOps, 0, ImplicitOps, ImplicitOps,
-       0, 0, ByteOp | DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM
+       0, 0, Group | Group4, Group | Group5,
 };
 
 static u16 twobyte_table[256] = {
        /* 0x00 - 0x0F */
-       0, SrcMem | ModRM | DstReg, 0, 0, 0, 0, ImplicitOps, 0,
+       0, Group | GroupDual | Group7, 0, 0, 0, 0, ImplicitOps, 0,
        ImplicitOps, ImplicitOps, 0, 0, 0, ImplicitOps | ModRM, 0, 0,
        /* 0x10 - 0x1F */
        0, 0, 0, 0, 0, 0, 0, 0, ImplicitOps | ModRM, 0, 0, 0, 0, 0, 0, 0,
@@ -229,6 +236,56 @@ static u16 twobyte_table[256] = {
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
+static u16 group_table[] = {
+       [Group1_80*8] =
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       [Group1_81*8] =
+       DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
+       DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
+       DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
+       DstMem | SrcImm | ModRM, DstMem | SrcImm | ModRM,
+       [Group1_82*8] =
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       ByteOp | DstMem | SrcImm | ModRM, ByteOp | DstMem | SrcImm | ModRM,
+       [Group1_83*8] =
+       DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
+       DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
+       DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
+       DstMem | SrcImmByte | ModRM, DstMem | SrcImmByte | ModRM,
+       [Group1A*8] =
+       DstMem | SrcNone | ModRM | Mov | Stack, 0, 0, 0, 0, 0, 0, 0,
+       [Group3_Byte*8] =
+       ByteOp | SrcImm | DstMem | ModRM, 0,
+       ByteOp | DstMem | SrcNone | ModRM, ByteOp | DstMem | SrcNone | ModRM,
+       0, 0, 0, 0,
+       [Group3*8] =
+       DstMem | SrcImm | ModRM | SrcImm, 0,
+       DstMem | SrcNone | ModRM, ByteOp | DstMem | SrcNone | ModRM,
+       0, 0, 0, 0,
+       [Group4*8] =
+       ByteOp | DstMem | SrcNone | ModRM, ByteOp | DstMem | SrcNone | ModRM,
+       0, 0, 0, 0, 0, 0,
+       [Group5*8] =
+       DstMem | SrcNone | ModRM, DstMem | SrcNone | ModRM, 0, 0,
+       SrcMem | ModRM, 0, SrcMem | ModRM | Stack, 0,
+       [Group7*8] =
+       0, 0, ModRM | SrcMem, ModRM | SrcMem,
+       SrcNone | ModRM | DstMem | Mov, 0,
+       SrcMem16 | ModRM | Mov, SrcMem | ModRM | ByteOp,
+};
+
+static u16 group2_table[] = {
+       [Group7*8] =
+       SrcNone | ModRM, 0, 0, 0,
+       SrcNone | ModRM | DstMem | Mov, 0,
+       SrcMem16 | ModRM | Mov, 0,
+};
+
 /* EFLAGS bit definitions. */
 #define EFLG_OF (1<<11)
 #define EFLG_DF (1<<10)
@@ -317,7 +374,7 @@ static u16 twobyte_table[256] = {
 
 #define __emulate_2op(_op,_src,_dst,_eflags,_bx,_by,_wx,_wy,_lx,_ly,_qx,_qy) \
        do {                                                                 \
-               unsigned long _tmp;                                          \
+               unsigned long __tmp;                                         \
                switch ((_dst).bytes) {                                      \
                case 1:                                                      \
                        __asm__ __volatile__ (                               \
@@ -325,7 +382,7 @@ static u16 twobyte_table[256] = {
                                _op"b %"_bx"3,%1; "                          \
                                _POST_EFLAGS("0", "4", "2")                  \
                                : "=m" (_eflags), "=m" ((_dst).val),         \
-                                 "=&r" (_tmp)                               \
+                                 "=&r" (__tmp)                              \
                                : _by ((_src).val), "i" (EFLAGS_MASK));      \
                        break;                                               \
                default:                                                     \
@@ -426,29 +483,40 @@ static u16 twobyte_table[256] = {
        (_type)_x;                                                      \
 })
 
+static inline unsigned long ad_mask(struct decode_cache *c)
+{
+       return (1UL << (c->ad_bytes << 3)) - 1;
+}
+
 /* Access/update address held in a register, based on addressing mode. */
-#define address_mask(reg)                                              \
-       ((c->ad_bytes == sizeof(unsigned long)) ?                       \
-               (reg) : ((reg) & ((1UL << (c->ad_bytes << 3)) - 1)))
-#define register_address(base, reg)                                     \
-       ((base) + address_mask(reg))
-#define register_address_increment(reg, inc)                            \
-       do {                                                            \
-               /* signed type ensures sign extension to long */        \
-               int _inc = (inc);                                       \
-               if (c->ad_bytes == sizeof(unsigned long))               \
-                       (reg) += _inc;                                  \
-               else                                                    \
-                       (reg) = ((reg) &                                \
-                                ~((1UL << (c->ad_bytes << 3)) - 1)) |  \
-                               (((reg) + _inc) &                       \
-                                ((1UL << (c->ad_bytes << 3)) - 1));    \
-       } while (0)
+static inline unsigned long
+address_mask(struct decode_cache *c, unsigned long reg)
+{
+       if (c->ad_bytes == sizeof(unsigned long))
+               return reg;
+       else
+               return reg & ad_mask(c);
+}
 
-#define JMP_REL(rel)                                                   \
-       do {                                                            \
-               register_address_increment(c->eip, rel);                \
-       } while (0)
+static inline unsigned long
+register_address(struct decode_cache *c, unsigned long base, unsigned long reg)
+{
+       return base + address_mask(c, reg);
+}
+
+static inline void
+register_address_increment(struct decode_cache *c, unsigned long *reg, int inc)
+{
+       if (c->ad_bytes == sizeof(unsigned long))
+               *reg += inc;
+       else
+               *reg = (*reg & ~ad_mask(c)) | ((*reg + inc) & ad_mask(c));
+}
+
+static inline void jmp_rel(struct decode_cache *c, int rel)
+{
+       register_address_increment(c, &c->eip, rel);
+}
 
 static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
                              struct x86_emulate_ops *ops,
@@ -763,7 +831,7 @@ x86_decode_insn(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
        struct decode_cache *c = &ctxt->decode;
        int rc = 0;
        int mode = ctxt->mode;
-       int def_op_bytes, def_ad_bytes;
+       int def_op_bytes, def_ad_bytes, group;
 
        /* Shadow copy of register state. Committed on successful emulation. */
 
@@ -864,12 +932,24 @@ done_prefixes:
                        c->b = insn_fetch(u8, 1, c->eip);
                        c->d = twobyte_table[c->b];
                }
+       }
 
-               /* Unrecognised? */
-               if (c->d == 0) {
-                       DPRINTF("Cannot emulate %02x\n", c->b);
-                       return -1;
-               }
+       if (c->d & Group) {
+               group = c->d & GroupMask;
+               c->modrm = insn_fetch(u8, 1, c->eip);
+               --c->eip;
+
+               group = (group << 3) + ((c->modrm >> 3) & 7);
+               if ((c->d & GroupDual) && (c->modrm >> 6) == 3)
+                       c->d = group2_table[group];
+               else
+                       c->d = group_table[group];
+       }
+
+       /* Unrecognised? */
+       if (c->d == 0) {
+               DPRINTF("Cannot emulate %02x\n", c->b);
+               return -1;
        }
 
        if (mode == X86EMUL_MODE_PROT64 && (c->d & Stack))
@@ -924,6 +1004,7 @@ done_prefixes:
                 */
                if ((c->d & ModRM) && c->modrm_mod == 3) {
                        c->src.type = OP_REG;
+                       c->src.val = c->modrm_val;
                        break;
                }
                c->src.type = OP_MEM;
@@ -967,6 +1048,7 @@ done_prefixes:
        case DstMem:
                if ((c->d & ModRM) && c->modrm_mod == 3) {
                        c->dst.type = OP_REG;
+                       c->dst.val = c->dst.orig_val = c->modrm_val;
                        break;
                }
                c->dst.type = OP_MEM;
@@ -984,8 +1066,8 @@ static inline void emulate_push(struct x86_emulate_ctxt *ctxt)
        c->dst.type  = OP_MEM;
        c->dst.bytes = c->op_bytes;
        c->dst.val = c->src.val;
-       register_address_increment(c->regs[VCPU_REGS_RSP], -c->op_bytes);
-       c->dst.ptr = (void *) register_address(ctxt->ss_base,
+       register_address_increment(c, &c->regs[VCPU_REGS_RSP], -c->op_bytes);
+       c->dst.ptr = (void *) register_address(c, ctxt->ss_base,
                                               c->regs[VCPU_REGS_RSP]);
 }
 
@@ -995,13 +1077,13 @@ static inline int emulate_grp1a(struct x86_emulate_ctxt *ctxt,
        struct decode_cache *c = &ctxt->decode;
        int rc;
 
-       rc = ops->read_std(register_address(ctxt->ss_base,
+       rc = ops->read_std(register_address(c, ctxt->ss_base,
                                            c->regs[VCPU_REGS_RSP]),
                           &c->dst.val, c->dst.bytes, ctxt->vcpu);
        if (rc != 0)
                return rc;
 
-       register_address_increment(c->regs[VCPU_REGS_RSP], c->dst.bytes);
+       register_address_increment(c, &c->regs[VCPU_REGS_RSP], c->dst.bytes);
 
        return 0;
 }
@@ -1043,26 +1125,6 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
 
        switch (c->modrm_reg) {
        case 0 ... 1:   /* test */
-               /*
-                * Special case in Grp3: test has an immediate
-                * source operand.
-                */
-               c->src.type = OP_IMM;
-               c->src.ptr = (unsigned long *)c->eip;
-               c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               if (c->src.bytes == 8)
-                       c->src.bytes = 4;
-               switch (c->src.bytes) {
-               case 1:
-                       c->src.val = insn_fetch(s8, 1, c->eip);
-                       break;
-               case 2:
-                       c->src.val = insn_fetch(s16, 2, c->eip);
-                       break;
-               case 4:
-                       c->src.val = insn_fetch(s32, 4, c->eip);
-                       break;
-               }
                emulate_2op_SrcV("test", c->src, c->dst, ctxt->eflags);
                break;
        case 2: /* not */
@@ -1076,7 +1138,6 @@ static inline int emulate_grp3(struct x86_emulate_ctxt *ctxt,
                rc = X86EMUL_UNHANDLEABLE;
                break;
        }
-done:
        return rc;
 }
 
@@ -1084,7 +1145,6 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
                               struct x86_emulate_ops *ops)
 {
        struct decode_cache *c = &ctxt->decode;
-       int rc;
 
        switch (c->modrm_reg) {
        case 0: /* inc */
@@ -1094,36 +1154,11 @@ static inline int emulate_grp45(struct x86_emulate_ctxt *ctxt,
                emulate_1op("dec", c->dst, ctxt->eflags);
                break;
        case 4: /* jmp abs */
-               if (c->b == 0xff)
-                       c->eip = c->dst.val;
-               else {
-                       DPRINTF("Cannot emulate %02x\n", c->b);
-                       return X86EMUL_UNHANDLEABLE;
-               }
+               c->eip = c->src.val;
                break;
        case 6: /* push */
-
-               /* 64-bit mode: PUSH always pushes a 64-bit operand. */
-
-               if (ctxt->mode == X86EMUL_MODE_PROT64) {
-                       c->dst.bytes = 8;
-                       rc = ops->read_std((unsigned long)c->dst.ptr,
-                                          &c->dst.val, 8, ctxt->vcpu);
-                       if (rc != 0)
-                               return rc;
-               }
-               register_address_increment(c->regs[VCPU_REGS_RSP],
-                                          -c->dst.bytes);
-               rc = ops->write_emulated(register_address(ctxt->ss_base,
-                                   c->regs[VCPU_REGS_RSP]), &c->dst.val,
-                                   c->dst.bytes, ctxt->vcpu);
-               if (rc != 0)
-                       return rc;
-               c->dst.type = OP_NONE;
+               emulate_push(ctxt);
                break;
-       default:
-               DPRINTF("Cannot emulate %02x\n", c->b);
-               return X86EMUL_UNHANDLEABLE;
        }
        return 0;
 }
@@ -1361,19 +1396,19 @@ special_insn:
                c->dst.type  = OP_MEM;
                c->dst.bytes = c->op_bytes;
                c->dst.val = c->src.val;
-               register_address_increment(c->regs[VCPU_REGS_RSP],
+               register_address_increment(c, &c->regs[VCPU_REGS_RSP],
                                           -c->op_bytes);
                c->dst.ptr = (void *) register_address(
-                       ctxt->ss_base, c->regs[VCPU_REGS_RSP]);
+                       c, ctxt->ss_base, c->regs[VCPU_REGS_RSP]);
                break;
        case 0x58 ... 0x5f: /* pop reg */
        pop_instruction:
-               if ((rc = ops->read_std(register_address(ctxt->ss_base,
+               if ((rc = ops->read_std(register_address(c, ctxt->ss_base,
                        c->regs[VCPU_REGS_RSP]), c->dst.ptr,
                        c->op_bytes, ctxt->vcpu)) != 0)
                        goto done;
 
-               register_address_increment(c->regs[VCPU_REGS_RSP],
+               register_address_increment(c, &c->regs[VCPU_REGS_RSP],
                                           c->op_bytes);
                c->dst.type = OP_NONE;  /* Disable writeback. */
                break;
@@ -1393,9 +1428,9 @@ special_insn:
                                1,
                                (c->d & ByteOp) ? 1 : c->op_bytes,
                                c->rep_prefix ?
-                               address_mask(c->regs[VCPU_REGS_RCX]) : 1,
+                               address_mask(c, c->regs[VCPU_REGS_RCX]) : 1,
                                (ctxt->eflags & EFLG_DF),
-                               register_address(ctxt->es_base,
+                               register_address(c, ctxt->es_base,
                                                 c->regs[VCPU_REGS_RDI]),
                                c->rep_prefix,
                                c->regs[VCPU_REGS_RDX]) == 0) {
@@ -1409,9 +1444,9 @@ special_insn:
                                0,
                                (c->d & ByteOp) ? 1 : c->op_bytes,
                                c->rep_prefix ?
-                               address_mask(c->regs[VCPU_REGS_RCX]) : 1,
+                               address_mask(c, c->regs[VCPU_REGS_RCX]) : 1,
                                (ctxt->eflags & EFLG_DF),
-                               register_address(c->override_base ?
+                               register_address(c, c->override_base ?
                                                        *c->override_base :
                                                        ctxt->ds_base,
                                                 c->regs[VCPU_REGS_RSI]),
@@ -1425,7 +1460,7 @@ special_insn:
                int rel = insn_fetch(s8, 1, c->eip);
 
                if (test_cc(c->b, ctxt->eflags))
-                       JMP_REL(rel);
+                       jmp_rel(c, rel);
                break;
        }
        case 0x80 ... 0x83:     /* Grp1 */
@@ -1477,7 +1512,7 @@ special_insn:
        case 0x88 ... 0x8b:     /* mov */
                goto mov;
        case 0x8d: /* lea r16/r32, m */
-               c->dst.val = c->modrm_val;
+               c->dst.val = c->modrm_ea;
                break;
        case 0x8f:              /* pop (sole member of Grp1a) */
                rc = emulate_grp1a(ctxt, ops);
@@ -1501,27 +1536,27 @@ special_insn:
        case 0xa4 ... 0xa5:     /* movs */
                c->dst.type = OP_MEM;
                c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               c->dst.ptr = (unsigned long *)register_address(
+               c->dst.ptr = (unsigned long *)register_address(c,
                                                   ctxt->es_base,
                                                   c->regs[VCPU_REGS_RDI]);
-               if ((rc = ops->read_emulated(register_address(
+               if ((rc = ops->read_emulated(register_address(c,
                      c->override_base ? *c->override_base :
                                        ctxt->ds_base,
                                        c->regs[VCPU_REGS_RSI]),
                                        &c->dst.val,
                                        c->dst.bytes, ctxt->vcpu)) != 0)
                        goto done;
-               register_address_increment(c->regs[VCPU_REGS_RSI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RSI],
                                       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
                                                           : c->dst.bytes);
-               register_address_increment(c->regs[VCPU_REGS_RDI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RDI],
                                       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
                                                           : c->dst.bytes);
                break;
        case 0xa6 ... 0xa7:     /* cmps */
                c->src.type = OP_NONE; /* Disable writeback. */
                c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               c->src.ptr = (unsigned long *)register_address(
+               c->src.ptr = (unsigned long *)register_address(c,
                                c->override_base ? *c->override_base :
                                                   ctxt->ds_base,
                                                   c->regs[VCPU_REGS_RSI]);
@@ -1533,7 +1568,7 @@ special_insn:
 
                c->dst.type = OP_NONE; /* Disable writeback. */
                c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               c->dst.ptr = (unsigned long *)register_address(
+               c->dst.ptr = (unsigned long *)register_address(c,
                                                   ctxt->es_base,
                                                   c->regs[VCPU_REGS_RDI]);
                if ((rc = ops->read_emulated((unsigned long)c->dst.ptr,
@@ -1546,10 +1581,10 @@ special_insn:
 
                emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
 
-               register_address_increment(c->regs[VCPU_REGS_RSI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RSI],
                                       (ctxt->eflags & EFLG_DF) ? -c->src.bytes
                                                                  : c->src.bytes);
-               register_address_increment(c->regs[VCPU_REGS_RDI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RDI],
                                       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
                                                                  : c->dst.bytes);
 
@@ -1557,11 +1592,11 @@ special_insn:
        case 0xaa ... 0xab:     /* stos */
                c->dst.type = OP_MEM;
                c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-               c->dst.ptr = (unsigned long *)register_address(
+               c->dst.ptr = (unsigned long *)register_address(c,
                                                   ctxt->es_base,
                                                   c->regs[VCPU_REGS_RDI]);
                c->dst.val = c->regs[VCPU_REGS_RAX];
-               register_address_increment(c->regs[VCPU_REGS_RDI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RDI],
                                       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
                                                           : c->dst.bytes);
                break;
@@ -1569,7 +1604,7 @@ special_insn:
                c->dst.type = OP_REG;
                c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
                c->dst.ptr = (unsigned long *)&c->regs[VCPU_REGS_RAX];
-               if ((rc = ops->read_emulated(register_address(
+               if ((rc = ops->read_emulated(register_address(c,
                                c->override_base ? *c->override_base :
                                                   ctxt->ds_base,
                                                 c->regs[VCPU_REGS_RSI]),
@@ -1577,7 +1612,7 @@ special_insn:
                                                 c->dst.bytes,
                                                 ctxt->vcpu)) != 0)
                        goto done;
-               register_address_increment(c->regs[VCPU_REGS_RSI],
+               register_address_increment(c, &c->regs[VCPU_REGS_RSI],
                                       (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
                                                           : c->dst.bytes);
                break;
@@ -1616,14 +1651,14 @@ special_insn:
                        goto cannot_emulate;
                }
                c->src.val = (unsigned long) c->eip;
-               JMP_REL(rel);
+               jmp_rel(c, rel);
                c->op_bytes = c->ad_bytes;
                emulate_push(ctxt);
                break;
        }
        case 0xe9: /* jmp rel */
        case 0xeb: /* jmp rel short */
-               JMP_REL(c->src.val);
+               jmp_rel(c, c->src.val);
                c->dst.type = OP_NONE; /* Disable writeback. */
                break;
        case 0xf4:              /* hlt */
@@ -1690,6 +1725,8 @@ twobyte_insn:
                                goto done;
 
                        kvm_emulate_hypercall(ctxt->vcpu);
+                       /* Disable writeback. */
+                       c->dst.type = OP_NONE;
                        break;
                case 2: /* lgdt */
                        rc = read_descriptor(ctxt, ops, c->src.ptr,
@@ -1697,6 +1734,8 @@ twobyte_insn:
                        if (rc)
                                goto done;
                        realmode_lgdt(ctxt->vcpu, size, address);
+                       /* Disable writeback. */
+                       c->dst.type = OP_NONE;
                        break;
                case 3: /* lidt/vmmcall */
                        if (c->modrm_mod == 3 && c->modrm_rm == 1) {
@@ -1712,27 +1751,25 @@ twobyte_insn:
                                        goto done;
                                realmode_lidt(ctxt->vcpu, size, address);
                        }
+                       /* Disable writeback. */
+                       c->dst.type = OP_NONE;
                        break;
                case 4: /* smsw */
-                       if (c->modrm_mod != 3)
-                               goto cannot_emulate;
-                       *(u16 *)&c->regs[c->modrm_rm]
-                               = realmode_get_cr(ctxt->vcpu, 0);
+                       c->dst.bytes = 2;
+                       c->dst.val = realmode_get_cr(ctxt->vcpu, 0);
                        break;
                case 6: /* lmsw */
-                       if (c->modrm_mod != 3)
-                               goto cannot_emulate;
-                       realmode_lmsw(ctxt->vcpu, (u16)c->modrm_val,
-                                                 &ctxt->eflags);
+                       realmode_lmsw(ctxt->vcpu, (u16)c->src.val,
+                                     &ctxt->eflags);
                        break;
                case 7: /* invlpg*/
                        emulate_invlpg(ctxt->vcpu, memop);
+                       /* Disable writeback. */
+                       c->dst.type = OP_NONE;
                        break;
                default:
                        goto cannot_emulate;
                }
-               /* Disable writeback. */
-               c->dst.type = OP_NONE;
                break;
        case 0x06:
                emulate_clts(ctxt->vcpu);
@@ -1823,7 +1860,7 @@ twobyte_insn:
                        goto cannot_emulate;
                }
                if (test_cc(c->b, ctxt->eflags))
-                       JMP_REL(rel);
+                       jmp_rel(c, rel);
                c->dst.type = OP_NONE;
                break;
        }