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KVM: x86 emulator: Use ctxt->_eip directly in do_insn_fetch_byte() 

Instead of passing ctxt->_eip from insn_fetch() call sites, get it from
ctxt in do_insn_fetch_byte().  This is done by replacing the argument
_eip of insn_fetch() with _ctxt, which should be better than letting the
macro use ctxt silently in its body.

Though this changes the place where ctxt->_eip is incremented from
insn_fetch() to do_insn_fetch_byte(), this does not have any real
effect.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Takuya Yoshikawa 2011-07-30 18:00:17 +09:00 committed by Avi Kivity
parent 743eeb0b01
commit 807941b121
1 changed files with 43 additions and 36 deletions
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79
arch/x86/kvm/emulate.c
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@ -651,18 +651,26 @@ static int segmented_read_std(struct x86_emulate_ctxt *ctxt,
return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception); return ctxt->ops->read_std(ctxt, linear, data, size, &ctxt->exception);
} }
static int do_insn_fetch_byte(struct x86_emulate_ctxt *ctxt, /*
unsigned long eip, u8 *dest) * Fetch the next byte of the instruction being emulated which is pointed to
* by ctxt->_eip, then increment ctxt->_eip.
*
* Also prefetch the remaining bytes of the instruction without crossing page
* boundary if they are not in fetch_cache yet.
*/
static int do_insn_fetch_byte(struct x86_emulate_ctxt *ctxt, u8 *dest)
{ {
struct fetch_cache *fc = &ctxt->fetch; struct fetch_cache *fc = &ctxt->fetch;
int rc; int rc;
int size, cur_size; int size, cur_size;
if (eip == fc->end) { if (ctxt->_eip == fc->end) {
unsigned long linear; unsigned long linear;
struct segmented_address addr = { .seg=VCPU_SREG_CS, .ea=eip}; struct segmented_address addr = { .seg = VCPU_SREG_CS,
.ea = ctxt->_eip };
cur_size = fc->end - fc->start; cur_size = fc->end - fc->start;
size = min(15UL - cur_size, PAGE_SIZE - offset_in_page(eip)); size = min(15UL - cur_size,
PAGE_SIZE - offset_in_page(ctxt->_eip));
rc = __linearize(ctxt, addr, size, false, true, &linear); rc = __linearize(ctxt, addr, size, false, true, &linear);
if (rc != X86EMUL_CONTINUE) if (rc != X86EMUL_CONTINUE)
return rc; return rc;
@ -672,20 +680,21 @@ static int do_insn_fetch_byte(struct x86_emulate_ctxt *ctxt,
return rc; return rc;
fc->end += size; fc->end += size;
} }
*dest = fc->data[eip - fc->start]; *dest = fc->data[ctxt->_eip - fc->start];
ctxt->_eip++;
return X86EMUL_CONTINUE; return X86EMUL_CONTINUE;
} }
static int do_insn_fetch(struct x86_emulate_ctxt *ctxt, static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
unsigned long eip, void *dest, unsigned size) void *dest, unsigned size)
{ {
int rc; int rc;
/* x86 instructions are limited to 15 bytes. */ /* x86 instructions are limited to 15 bytes. */
if (eip + size - ctxt->eip > 15) if (ctxt->_eip + size - ctxt->eip > 15)
return X86EMUL_UNHANDLEABLE; return X86EMUL_UNHANDLEABLE;
while (size--) { while (size--) {
rc = do_insn_fetch_byte(ctxt, eip++, dest++); rc = do_insn_fetch_byte(ctxt, dest++);
if (rc != X86EMUL_CONTINUE) if (rc != X86EMUL_CONTINUE)
return rc; return rc;
} }
@ -693,20 +702,18 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
} }
/* Fetch next part of the instruction being emulated. */ /* Fetch next part of the instruction being emulated. */
#define insn_fetch(_type, _size, _eip) \ #define insn_fetch(_type, _size, _ctxt) \
({ unsigned long _x; \ ({ unsigned long _x; \
rc = do_insn_fetch(ctxt, (_eip), &_x, (_size)); \ rc = do_insn_fetch(_ctxt, &_x, (_size)); \
if (rc != X86EMUL_CONTINUE) \ if (rc != X86EMUL_CONTINUE) \
goto done; \ goto done; \
(_eip) += (_size); \
(_type)_x; \ (_type)_x; \
}) })
#define insn_fetch_arr(_arr, _size, _eip) \ #define insn_fetch_arr(_arr, _size, _ctxt) \
({ rc = do_insn_fetch(ctxt, (_eip), _arr, (_size)); \ ({ rc = do_insn_fetch(_ctxt, _arr, (_size)); \
if (rc != X86EMUL_CONTINUE) \ if (rc != X86EMUL_CONTINUE) \
goto done; \ goto done; \
(_eip) += (_size); \
}) })
/* /*
@ -894,7 +901,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
ctxt->modrm_rm = base_reg = (ctxt->rex_prefix & 1) << 3; /* REG.B */ ctxt->modrm_rm = base_reg = (ctxt->rex_prefix & 1) << 3; /* REG.B */
} }
ctxt->modrm = insn_fetch(u8, 1, ctxt->_eip); ctxt->modrm = insn_fetch(u8, 1, ctxt);
ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6; ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6;
ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3; ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3;
ctxt->modrm_rm |= (ctxt->modrm & 0x07); ctxt->modrm_rm |= (ctxt->modrm & 0x07);
@ -928,13 +935,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) { switch (ctxt->modrm_mod) {
case 0: case 0:
if (ctxt->modrm_rm == 6) if (ctxt->modrm_rm == 6)
modrm_ea += insn_fetch(u16, 2, ctxt->_eip); modrm_ea += insn_fetch(u16, 2, ctxt);
break; break;
case 1: case 1:
modrm_ea += insn_fetch(s8, 1, ctxt->_eip); modrm_ea += insn_fetch(s8, 1, ctxt);
break; break;
case 2: case 2:
modrm_ea += insn_fetch(u16, 2, ctxt->_eip); modrm_ea += insn_fetch(u16, 2, ctxt);
break; break;
} }
switch (ctxt->modrm_rm) { switch (ctxt->modrm_rm) {
@ -971,13 +978,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
} else { } else {
/* 32/64-bit ModR/M decode. */ /* 32/64-bit ModR/M decode. */
if ((ctxt->modrm_rm & 7) == 4) { if ((ctxt->modrm_rm & 7) == 4) {
sib = insn_fetch(u8, 1, ctxt->_eip); sib = insn_fetch(u8, 1, ctxt);
index_reg |= (sib >> 3) & 7; index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7; base_reg |= sib & 7;
scale = sib >> 6; scale = sib >> 6;
if ((base_reg & 7) == 5 && ctxt->modrm_mod == 0) if ((base_reg & 7) == 5 && ctxt->modrm_mod == 0)
modrm_ea += insn_fetch(s32, 4, ctxt->_eip); modrm_ea += insn_fetch(s32, 4, ctxt);
else else
modrm_ea += ctxt->regs[base_reg]; modrm_ea += ctxt->regs[base_reg];
if (index_reg != 4) if (index_reg != 4)
@ -990,13 +997,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) { switch (ctxt->modrm_mod) {
case 0: case 0:
if (ctxt->modrm_rm == 5) if (ctxt->modrm_rm == 5)
modrm_ea += insn_fetch(s32, 4, ctxt->_eip); modrm_ea += insn_fetch(s32, 4, ctxt);
break; break;
case 1: case 1:
modrm_ea += insn_fetch(s8, 1, ctxt->_eip); modrm_ea += insn_fetch(s8, 1, ctxt);
break; break;
case 2: case 2:
modrm_ea += insn_fetch(s32, 4, ctxt->_eip); modrm_ea += insn_fetch(s32, 4, ctxt);
break; break;
} }
} }
@ -1013,13 +1020,13 @@ static int decode_abs(struct x86_emulate_ctxt *ctxt,
op->type = OP_MEM; op->type = OP_MEM;
switch (ctxt->ad_bytes) { switch (ctxt->ad_bytes) {
case 2: case 2:
op->addr.mem.ea = insn_fetch(u16, 2, ctxt->_eip); op->addr.mem.ea = insn_fetch(u16, 2, ctxt);
break; break;
case 4: case 4:
op->addr.mem.ea = insn_fetch(u32, 4, ctxt->_eip); op->addr.mem.ea = insn_fetch(u32, 4, ctxt);
break; break;
case 8: case 8:
op->addr.mem.ea = insn_fetch(u64, 8, ctxt->_eip); op->addr.mem.ea = insn_fetch(u64, 8, ctxt);
break; break;
} }
done: done:
@ -3309,13 +3316,13 @@ static int decode_imm(struct x86_emulate_ctxt *ctxt, struct operand *op,
/* NB. Immediates are sign-extended as necessary. */ /* NB. Immediates are sign-extended as necessary. */
switch (op->bytes) { switch (op->bytes) {
case 1: case 1:
op->val = insn_fetch(s8, 1, ctxt->_eip); op->val = insn_fetch(s8, 1, ctxt);
break; break;
case 2: case 2:
op->val = insn_fetch(s16, 2, ctxt->_eip); op->val = insn_fetch(s16, 2, ctxt);
break; break;
case 4: case 4:
op->val = insn_fetch(s32, 4, ctxt->_eip); op->val = insn_fetch(s32, 4, ctxt);
break; break;
} }
if (!sign_extension) { if (!sign_extension) {
@ -3374,7 +3381,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
/* Legacy prefixes. */ /* Legacy prefixes. */
for (;;) { for (;;) {
switch (ctxt->b = insn_fetch(u8, 1, ctxt->_eip)) { switch (ctxt->b = insn_fetch(u8, 1, ctxt)) {
case 0x66: /* operand-size override */ case 0x66: /* operand-size override */
op_prefix = true; op_prefix = true;
/* switch between 2/4 bytes */ /* switch between 2/4 bytes */
@ -3430,7 +3437,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
/* Two-byte opcode? */ /* Two-byte opcode? */
if (ctxt->b == 0x0f) { if (ctxt->b == 0x0f) {
ctxt->twobyte = 1; ctxt->twobyte = 1;
ctxt->b = insn_fetch(u8, 1, ctxt->_eip); ctxt->b = insn_fetch(u8, 1, ctxt);
opcode = twobyte_table[ctxt->b]; opcode = twobyte_table[ctxt->b];
} }
ctxt->d = opcode.flags; ctxt->d = opcode.flags;
@ -3438,13 +3445,13 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
while (ctxt->d & GroupMask) { while (ctxt->d & GroupMask) {
switch (ctxt->d & GroupMask) { switch (ctxt->d & GroupMask) {
case Group: case Group:
ctxt->modrm = insn_fetch(u8, 1, ctxt->_eip); ctxt->modrm = insn_fetch(u8, 1, ctxt);
--ctxt->_eip; --ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7; goffset = (ctxt->modrm >> 3) & 7;
opcode = opcode.u.group[goffset]; opcode = opcode.u.group[goffset];
break; break;
case GroupDual: case GroupDual:
ctxt->modrm = insn_fetch(u8, 1, ctxt->_eip); ctxt->modrm = insn_fetch(u8, 1, ctxt);
--ctxt->_eip; --ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7; goffset = (ctxt->modrm >> 3) & 7;
if ((ctxt->modrm >> 6) == 3) if ((ctxt->modrm >> 6) == 3)
@ -3577,7 +3584,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
ctxt->src.type = OP_IMM; ctxt->src.type = OP_IMM;
ctxt->src.addr.mem.ea = ctxt->_eip; ctxt->src.addr.mem.ea = ctxt->_eip;
ctxt->src.bytes = ctxt->op_bytes + 2; ctxt->src.bytes = ctxt->op_bytes + 2;
insn_fetch_arr(ctxt->src.valptr, ctxt->src.bytes, ctxt->_eip); insn_fetch_arr(ctxt->src.valptr, ctxt->src.bytes, ctxt);
break; break;
case SrcMemFAddr: case SrcMemFAddr:
memop.bytes = ctxt->op_bytes + 2; memop.bytes = ctxt->op_bytes + 2;
@ -3630,7 +3637,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
ctxt->dst.type = OP_IMM; ctxt->dst.type = OP_IMM;
ctxt->dst.addr.mem.ea = ctxt->_eip; ctxt->dst.addr.mem.ea = ctxt->_eip;
ctxt->dst.bytes = 1; ctxt->dst.bytes = 1;
ctxt->dst.val = insn_fetch(u8, 1, ctxt->_eip); ctxt->dst.val = insn_fetch(u8, 1, ctxt);
break; break;
case DstMem: case DstMem:
case DstMem64: case DstMem64: