To be able to extract easily prefix decoding from x86_emulate_memop(), group all prefix decoding results in a structure called x86_prefix.
Signed-off-by: Laurent Vivier <[EMAIL PROTECTED]>
--
------------- [EMAIL PROTECTED] --------------
"Software is hard" - Donald Knuth
Index: kvm/drivers/kvm/x86_emulate.h
===================================================================
--- kvm.orig/drivers/kvm/x86_emulate.h 2007-07-31 17:00:22.000000000 +0200
+++ kvm/drivers/kvm/x86_emulate.h 2007-07-31 17:03:26.000000000 +0200
@@ -141,6 +141,21 @@
#define X86EMUL_MODE_PROT32 4 /* 32-bit protected mode. */
#define X86EMUL_MODE_PROT64 8 /* 64-bit (long) mode. */
+struct x86_prefix {
+ unsigned int op_bytes;
+ unsigned int ad_bytes;
+ int override_base;
+
+ u8 lock; /* LOCK prefix */
+ u8 rep; /* REP prefix */
+ u8 rex; /* REX prefix */
+
+ int index_reg;
+ int base_reg;
+ u8 modrm_reg;
+ u8 modrm_rm;
+};
+
/* Host execution mode. */
#if defined(__i386__)
#define X86EMUL_MODE_HOST X86EMUL_MODE_PROT32
Index: kvm/drivers/kvm/x86_emulate.c
===================================================================
--- kvm.orig/drivers/kvm/x86_emulate.c 2007-07-31 17:01:52.000000000 +0200
+++ kvm/drivers/kvm/x86_emulate.c 2007-07-31 17:07:30.000000000 +0200
@@ -430,18 +430,18 @@
/* Access/update address held in a register, based on addressing mode. */
#define register_address(base, reg) \
- ((base) + ((ad_bytes == sizeof(unsigned long)) ? (reg) : \
- ((reg) & ((1UL << (ad_bytes << 3)) - 1))))
+ ((base) + ((prefix.ad_bytes == sizeof(unsigned long)) ? (reg) : \
+ ((reg) & ((1UL << (prefix.ad_bytes << 3)) - 1))))
#define register_address_increment(reg, inc) \
do { \
/* signed type ensures sign extension to long */ \
int _inc = (inc); \
- if ( ad_bytes == sizeof(unsigned long) ) \
+ if ( prefix.ad_bytes == sizeof(unsigned long) ) \
(reg) += _inc; \
else \
- (reg) = ((reg) & ~((1UL << (ad_bytes << 3)) - 1)) | \
- (((reg) + _inc) & ((1UL << (ad_bytes << 3)) - 1)); \
+ (reg) = ((reg) & ~((1UL << (prefix.ad_bytes << 3)) -
1)) | \
+ (((reg) + _inc) & ((1UL << (prefix.ad_bytes << 3)) -
1)); \
} while (0)
/*
@@ -483,18 +483,18 @@
x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
{
unsigned d;
- u8 b, sib, twobyte = 0, rex_prefix = 0;
- u8 modrm, modrm_mod = 0, modrm_reg = 0, modrm_rm = 0;
- int override_base = -1;
- unsigned int op_bytes, ad_bytes, lock_prefix = 0, rep_prefix = 0, i;
+ u8 b, sib, twobyte = 0;
+ u8 modrm, modrm_mod = 0;
+ unsigned int i;
int rc = 0;
struct operand src, dst;
unsigned long cr2 = ctxt->cr2;
int mode = ctxt->mode;
unsigned long modrm_ea;
- int use_modrm_ea, index_reg = 0, base_reg = 0, scale, rip_relative = 0;
+ int use_modrm_ea, scale, rip_relative = 0;
int no_wb = 0;
u64 msr_data;
+ struct x86_prefix prefix;
/* Shadow copy of register state. Committed on successful emulation. */
unsigned long _regs[NR_VCPU_REGS];
@@ -502,19 +502,21 @@
unsigned long modrm_val = 0;
memcpy(_regs, ctxt->vcpu->regs, sizeof _regs);
+ memset(&prefix, 0, sizeof(prefix));
+ prefix.override_base = -1;
switch (mode) {
case X86EMUL_MODE_REAL:
case X86EMUL_MODE_PROT16:
- op_bytes = ad_bytes = 2;
+ prefix.op_bytes = prefix.ad_bytes = 2;
break;
case X86EMUL_MODE_PROT32:
- op_bytes = ad_bytes = 4;
+ prefix.op_bytes = prefix.ad_bytes = 4;
break;
#ifdef CONFIG_X86_64
case X86EMUL_MODE_PROT64:
- op_bytes = 4;
- ad_bytes = 8;
+ prefix.op_bytes = 4;
+ prefix.ad_bytes = 8;
break;
#endif
default:
@@ -525,37 +527,37 @@
for (i = 0; i < 8; i++) {
switch (b = insn_fetch(u8, 1, _eip)) {
case 0x66: /* operand-size override */
- op_bytes ^= 6; /* switch between 2/4 bytes */
+ prefix.op_bytes ^= 6; /* switch between 2/4 bytes */
break;
case 0x67: /* address-size override */
if (mode == X86EMUL_MODE_PROT64)
- ad_bytes ^= 12; /* switch between 4/8 bytes */
+ prefix.ad_bytes ^= 12; /* switch between 4/8
bytes */
else
- ad_bytes ^= 6; /* switch between 2/4 bytes */
+ prefix.ad_bytes ^= 6; /* switch between 2/4
bytes */
break;
case 0x2e: /* CS override */
- override_base = X86EMUL_BASE_CS;
+ prefix.override_base = X86EMUL_BASE_CS;
break;
case 0x3e: /* DS override */
- override_base = X86EMUL_BASE_DS;
+ prefix.override_base = X86EMUL_BASE_DS;
break;
case 0x26: /* ES override */
- override_base = X86EMUL_BASE_ES;
+ prefix.override_base = X86EMUL_BASE_ES;
break;
case 0x64: /* FS override */
- override_base = X86EMUL_BASE_FS;
+ prefix.override_base = X86EMUL_BASE_FS;
break;
case 0x65: /* GS override */
- override_base = X86EMUL_BASE_GS;
+ prefix.override_base = X86EMUL_BASE_GS;
break;
case 0x36: /* SS override */
- override_base = X86EMUL_BASE_SS;
+ prefix.override_base = X86EMUL_BASE_SS;
break;
case 0xf0: /* LOCK */
- lock_prefix = 1;
+ prefix.lock = 1;
break;
case 0xf3: /* REP/REPE/REPZ */
- rep_prefix = 1;
+ prefix.rep = 1;
break;
case 0xf2: /* REPNE/REPNZ */
break;
@@ -568,12 +570,12 @@
/* REX prefix. */
if ((mode == X86EMUL_MODE_PROT64) && ((b & 0xf0) == 0x40)) {
- rex_prefix = b;
+ prefix.rex = b;
if (b & 8)
- op_bytes = 8; /* REX.W */
- modrm_reg = (b & 4) << 1; /* REX.R */
- index_reg = (b & 2) << 2; /* REX.X */
- modrm_rm = base_reg = (b & 1) << 3; /* REG.B */
+ prefix.op_bytes = 8; /* REX.W */
+ prefix.modrm_reg = (b & 4) << 1; /* REX.R */
+ prefix.index_reg = (b & 2) << 2; /* REX.X */
+ prefix.modrm_rm = prefix.base_reg = (b & 1) << 3; /* REG.B */
b = insn_fetch(u8, 1, _eip);
}
@@ -596,18 +598,18 @@
if (d & ModRM) {
modrm = insn_fetch(u8, 1, _eip);
modrm_mod |= (modrm & 0xc0) >> 6;
- modrm_reg |= (modrm & 0x38) >> 3;
- modrm_rm |= (modrm & 0x07);
+ prefix.modrm_reg |= (modrm & 0x38) >> 3;
+ prefix.modrm_rm |= (modrm & 0x07);
modrm_ea = 0;
use_modrm_ea = 1;
if (modrm_mod == 3) {
modrm_val = *(unsigned long *)
- decode_register(modrm_rm, _regs, d & ByteOp);
+ decode_register(prefix.modrm_rm, _regs, d &
ByteOp);
goto modrm_done;
}
- if (ad_bytes == 2) {
+ if (prefix.ad_bytes == 2) {
unsigned bx = _regs[VCPU_REGS_RBX];
unsigned bp = _regs[VCPU_REGS_RBP];
unsigned si = _regs[VCPU_REGS_RSI];
@@ -616,7 +618,7 @@
/* 16-bit ModR/M decode. */
switch (modrm_mod) {
case 0:
- if (modrm_rm == 6)
+ if (prefix.modrm_rm == 6)
modrm_ea += insn_fetch(u16, 2, _eip);
break;
case 1:
@@ -626,7 +628,7 @@
modrm_ea += insn_fetch(u16, 2, _eip);
break;
}
- switch (modrm_rm) {
+ switch (prefix.modrm_rm) {
case 0:
modrm_ea += bx + si;
break;
@@ -653,52 +655,52 @@
modrm_ea += bx;
break;
}
- if (modrm_rm == 2 || modrm_rm == 3 ||
- (modrm_rm == 6 && modrm_mod != 0))
- if (override_base == -1)
- override_base = X86EMUL_BASE_SS;
+ if (prefix.modrm_rm == 2 || prefix.modrm_rm == 3 ||
+ (prefix.modrm_rm == 6 && modrm_mod != 0))
+ if (prefix.override_base == -1)
+ prefix.override_base = X86EMUL_BASE_SS;
modrm_ea = (u16)modrm_ea;
} else {
/* 32/64-bit ModR/M decode. */
- switch (modrm_rm) {
+ switch (prefix.modrm_rm) {
case 4:
case 12:
sib = insn_fetch(u8, 1, _eip);
- index_reg |= (sib >> 3) & 7;
- base_reg |= sib & 7;
+ prefix.index_reg |= (sib >> 3) & 7;
+ prefix.base_reg |= sib & 7;
scale = sib >> 6;
- switch (base_reg) {
+ switch (prefix.base_reg) {
case 5:
if (modrm_mod != 0)
- modrm_ea += _regs[base_reg];
+ modrm_ea +=
_regs[prefix.base_reg];
else
modrm_ea += insn_fetch(s32, 4,
_eip);
break;
default:
- modrm_ea += _regs[base_reg];
+ modrm_ea += _regs[prefix.base_reg];
}
- switch (index_reg) {
+ switch (prefix.index_reg) {
case 4:
break;
default:
- modrm_ea += _regs[index_reg] << scale;
+ modrm_ea += _regs[prefix.index_reg] <<
scale;
}
break;
case 5:
if (modrm_mod != 0)
- modrm_ea += _regs[modrm_rm];
+ modrm_ea += _regs[prefix.modrm_rm];
else if (mode == X86EMUL_MODE_PROT64)
rip_relative = 1;
break;
default:
- modrm_ea += _regs[modrm_rm];
+ modrm_ea += _regs[prefix.modrm_rm];
break;
}
switch (modrm_mod) {
case 0:
- if (modrm_rm == 5)
+ if (prefix.modrm_rm == 5)
modrm_ea += insn_fetch(s32, 4, _eip);
break;
case 1:
@@ -709,15 +711,15 @@
break;
}
}
- if (override_base == -1)
- override_base = X86EMUL_BASE_DS;
+ if (prefix.override_base == -1)
+ prefix.override_base = X86EMUL_BASE_DS;
if (mode == X86EMUL_MODE_PROT64 &&
- override_base != X86EMUL_BASE_FS &&
- override_base != X86EMUL_BASE_GS)
- override_base = -1;
+ prefix.override_base != X86EMUL_BASE_FS &&
+ prefix.override_base != X86EMUL_BASE_GS)
+ prefix.override_base = -1;
- if (override_base != -1)
- modrm_ea += ctxt->base[override_base];
+ if (prefix.override_base != -1)
+ modrm_ea += ctxt->base[prefix.override_base];
if (rip_relative) {
modrm_ea += _eip;
@@ -729,13 +731,13 @@
if (d & ByteOp)
modrm_ea += 1;
else
- if (op_bytes == 8)
+ if (prefix.op_bytes == 8)
modrm_ea += 4;
else
- modrm_ea += op_bytes;
+ modrm_ea += prefix.op_bytes;
}
}
- if (ad_bytes != 8)
+ if (prefix.ad_bytes != 8)
modrm_ea = (u32)modrm_ea;
cr2 = modrm_ea;
modrm_done:
@@ -752,13 +754,13 @@
case SrcReg:
src.type = OP_REG;
if (d & ByteOp) {
- src.ptr = decode_register(modrm_reg, _regs,
- (rex_prefix == 0));
+ src.ptr = decode_register(prefix.modrm_reg, _regs,
+ (prefix.rex == 0));
src.val = src.orig_val = *(u8 *) src.ptr;
src.bytes = 1;
} else {
- src.ptr = decode_register(modrm_reg, _regs, 0);
- switch ((src.bytes = op_bytes)) {
+ src.ptr = decode_register(prefix.modrm_reg, _regs, 0);
+ switch ((src.bytes = prefix.op_bytes)) {
case 2:
src.val = src.orig_val = *(u16 *) src.ptr;
break;
@@ -778,7 +780,7 @@
src.bytes = 4;
goto srcmem_common;
case SrcMem:
- src.bytes = (d & ByteOp) ? 1 : op_bytes;
+ src.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
srcmem_common:
src.type = OP_MEM;
src.ptr = (unsigned long *)cr2;
@@ -790,7 +792,7 @@
case SrcImm:
src.type = OP_IMM;
src.ptr = (unsigned long *)_eip;
- src.bytes = (d & ByteOp) ? 1 : op_bytes;
+ src.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
if (src.bytes == 8)
src.bytes = 4;
/* NB. Immediates are sign-extended as necessary. */
@@ -823,13 +825,13 @@
dst.type = OP_REG;
if ((d & ByteOp)
&& !(twobyte && (b == 0xb6 || b == 0xb7))) {
- dst.ptr = decode_register(modrm_reg, _regs,
- (rex_prefix == 0));
+ dst.ptr = decode_register(prefix.modrm_reg, _regs,
+ (prefix.rex == 0));
dst.val = *(u8 *) dst.ptr;
dst.bytes = 1;
} else {
- dst.ptr = decode_register(modrm_reg, _regs, 0);
- switch ((dst.bytes = op_bytes)) {
+ dst.ptr = decode_register(prefix.modrm_reg, _regs, 0);
+ switch ((dst.bytes = prefix.op_bytes)) {
case 2:
dst.val = *(u16 *)dst.ptr;
break;
@@ -845,7 +847,7 @@
case DstMem:
dst.type = OP_MEM;
dst.ptr = (unsigned long *)cr2;
- dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+ dst.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
if (d & BitOp) {
unsigned long mask = ~(dst.bytes * 8 - 1);
@@ -901,7 +903,7 @@
dst.val = (s32) src.val;
break;
case 0x80 ... 0x83: /* Grp1 */
- switch (modrm_reg) {
+ switch (prefix.modrm_reg) {
case 0:
goto add;
case 1:
@@ -945,16 +947,16 @@
* prefix.
*/
dst.val = src.val;
- lock_prefix = 1;
+ prefix.lock = 1;
break;
case 0xa0 ... 0xa1: /* mov */
dst.ptr = (unsigned long *)&_regs[VCPU_REGS_RAX];
dst.val = src.val;
- _eip += ad_bytes; /* skip src displacement */
+ _eip += prefix.ad_bytes; /* skip src displacement */
break;
case 0xa2 ... 0xa3: /* mov */
dst.val = (unsigned long)_regs[VCPU_REGS_RAX];
- _eip += ad_bytes; /* skip dst displacement */
+ _eip += prefix.ad_bytes; /* skip dst displacement */
break;
case 0x88 ... 0x8b: /* mov */
case 0xc6 ... 0xc7: /* mov (sole member of Grp11) */
@@ -973,7 +975,7 @@
break;
case 0xc0 ... 0xc1:
grp2: /* Grp2 */
- switch (modrm_reg) {
+ switch (prefix.modrm_reg) {
case 0: /* rol */
emulate_2op_SrcB("rol", src, dst, _eflags);
break;
@@ -1005,7 +1007,7 @@
src.val = _regs[VCPU_REGS_RCX];
goto grp2;
case 0xf6 ... 0xf7: /* Grp3 */
- switch (modrm_reg) {
+ switch (prefix.modrm_reg) {
case 0 ... 1: /* test */
/*
* Special case in Grp3: test has an immediate
@@ -1013,7 +1015,7 @@
*/
src.type = OP_IMM;
src.ptr = (unsigned long *)_eip;
- src.bytes = (d & ByteOp) ? 1 : op_bytes;
+ src.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
if (src.bytes == 8)
src.bytes = 4;
switch (src.bytes) {
@@ -1039,7 +1041,7 @@
}
break;
case 0xfe ... 0xff: /* Grp4/Grp5 */
- switch (modrm_reg) {
+ switch (prefix.modrm_reg) {
case 0: /* inc */
emulate_1op("inc", dst, _eflags);
break;
@@ -1091,7 +1093,7 @@
}
break;
case OP_MEM:
- if (lock_prefix)
+ if (prefix.lock)
rc = ops->cmpxchg_emulated((unsigned long)dst.
ptr, &dst.orig_val,
&dst.val, dst.bytes,
@@ -1118,7 +1120,7 @@
special_insn:
if (twobyte)
goto twobyte_special_insn;
- if (rep_prefix) {
+ if (prefix.rep) {
if (_regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = _eip;
goto done;
@@ -1129,13 +1131,13 @@
switch (b) {
case 0xa4 ... 0xa5: /* movs */
dst.type = OP_MEM;
- dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+ dst.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
dst.ptr = (unsigned long *)register_address(
ctxt->base[X86EMUL_BASE_ES],
_regs[VCPU_REGS_RDI]);
if ((rc = ops->read_emulated(register_address(
- (override_base != -1) ?
- ctxt->base[override_base] : ctxt->base[X86EMUL_BASE_DS],
+ (prefix.override_base != -1) ?
+ ctxt->base[prefix.override_base] :
ctxt->base[X86EMUL_BASE_DS],
_regs[VCPU_REGS_RSI]), &dst.val, dst.bytes, ctxt->vcpu))
!= 0)
goto done;
register_address_increment(_regs[VCPU_REGS_RSI],
@@ -1148,7 +1150,7 @@
goto cannot_emulate;
case 0xaa ... 0xab: /* stos */
dst.type = OP_MEM;
- dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+ dst.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
dst.ptr = (unsigned long *)cr2;
dst.val = _regs[VCPU_REGS_RAX];
register_address_increment(_regs[VCPU_REGS_RDI],
@@ -1156,7 +1158,7 @@
break;
case 0xac ... 0xad: /* lods */
dst.type = OP_REG;
- dst.bytes = (d & ByteOp) ? 1 : op_bytes;
+ dst.bytes = (d & ByteOp) ? 1 : prefix.op_bytes;
dst.ptr = (unsigned long *)&_regs[VCPU_REGS_RAX];
if ((rc = ops->read_emulated(cr2, &dst.val, dst.bytes,
ctxt->vcpu)) != 0)
@@ -1179,11 +1181,11 @@
pop_instruction:
if ((rc = ops->read_std(
register_address(ctxt->base[X86EMUL_BASE_SS],
- _regs[VCPU_REGS_RSP]), dst.ptr, op_bytes, ctxt->vcpu))
+ _regs[VCPU_REGS_RSP]), dst.ptr, prefix.op_bytes,
ctxt->vcpu))
!= 0)
goto done;
- register_address_increment(_regs[VCPU_REGS_RSP], op_bytes);
+ register_address_increment(_regs[VCPU_REGS_RSP],
prefix.op_bytes);
no_wb = 1; /* Disable writeback. */
break;
}
@@ -1194,20 +1196,20 @@
case 0x01: /* lgdt, lidt, lmsw */
/* Disable writeback. */
no_wb = 1;
- switch (modrm_reg) {
+ switch (prefix.modrm_reg) {
u16 size;
unsigned long address;
case 2: /* lgdt */
rc = read_descriptor(ctxt, ops, src.ptr,
- &size, &address, op_bytes);
+ &size, &address, prefix.op_bytes);
if (rc)
goto done;
realmode_lgdt(ctxt->vcpu, size, address);
break;
case 3: /* lidt */
rc = read_descriptor(ctxt, ops, src.ptr,
- &size, &address, op_bytes);
+ &size, &address, prefix.op_bytes);
if (rc)
goto done;
realmode_lidt(ctxt->vcpu, size, address);
@@ -1215,7 +1217,7 @@
case 4: /* smsw */
if (modrm_mod != 3)
goto cannot_emulate;
- *(u16 *)&_regs[modrm_rm]
+ *(u16 *)&_regs[prefix.modrm_rm]
= realmode_get_cr(ctxt->vcpu, 0);
break;
case 6: /* lmsw */
@@ -1233,12 +1235,12 @@
case 0x21: /* mov from dr to reg */
if (modrm_mod != 3)
goto cannot_emulate;
- rc = emulator_get_dr(ctxt, modrm_reg, &_regs[modrm_rm]);
+ rc = emulator_get_dr(ctxt, prefix.modrm_reg,
&_regs[prefix.modrm_rm]);
break;
case 0x23: /* mov from reg to dr */
if (modrm_mod != 3)
goto cannot_emulate;
- rc = emulator_set_dr(ctxt, modrm_reg, _regs[modrm_rm]);
+ rc = emulator_set_dr(ctxt, prefix.modrm_reg,
_regs[prefix.modrm_rm]);
break;
case 0x40 ... 0x4f: /* cmov */
dst.val = dst.orig_val = src.val;
@@ -1310,7 +1312,7 @@
emulate_2op_SrcV_nobyte("bts", src, dst, _eflags);
break;
case 0xb6 ... 0xb7: /* movzx */
- dst.bytes = op_bytes;
+ dst.bytes = prefix.op_bytes;
dst.val = (d & ByteOp) ? (u8) src.val : (u16) src.val;
break;
case 0xbb:
@@ -1319,7 +1321,7 @@
emulate_2op_SrcV_nobyte("btc", src, dst, _eflags);
break;
case 0xba: /* Grp8 */
- switch (modrm_reg & 3) {
+ switch (prefix.modrm_reg & 3) {
case 0:
goto bt;
case 1:
@@ -1331,7 +1333,7 @@
}
break;
case 0xbe ... 0xbf: /* movsx */
- dst.bytes = op_bytes;
+ dst.bytes = prefix.op_bytes;
dst.val = (d & ByteOp) ? (s8) src.val : (s16) src.val;
break;
}
@@ -1352,12 +1354,12 @@
case 0x20: /* mov cr, reg */
if (modrm_mod != 3)
goto cannot_emulate;
- _regs[modrm_rm] = realmode_get_cr(ctxt->vcpu, modrm_reg);
+ _regs[prefix.modrm_rm] = realmode_get_cr(ctxt->vcpu,
prefix.modrm_reg);
break;
case 0x22: /* mov reg, cr */
if (modrm_mod != 3)
goto cannot_emulate;
- realmode_set_cr(ctxt->vcpu, modrm_reg, modrm_val, &_eflags);
+ realmode_set_cr(ctxt->vcpu, prefix.modrm_reg, modrm_val,
&_eflags);
break;
case 0x30:
/* wrmsr */
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