* [PATCH 1/4] KVM: x86 emulator: Use ctxt->_eip directly in do_insn_fetch_byte()
2011-07-30 8:58 [PATCH 0/4] KVM: x86 emulator: Clean up decoder a bit Takuya Yoshikawa
@ 2011-07-30 9:00 ` Takuya Yoshikawa
2011-07-30 9:01 ` [PATCH 2/4] KVM: x86 emulator: Drop _size argument from insn_fetch() Takuya Yoshikawa
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Takuya Yoshikawa @ 2011-07-30 9:00 UTC (permalink / raw)
To: avi, mtosatti; +Cc: kvm, yoshikawa.takuya
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
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>
---
arch/x86/kvm/emulate.c | 79 ++++++++++++++++++++++++++----------------------
1 files changed, 43 insertions(+), 36 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 6f08bc9..fbb2e3a 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -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);
}
-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;
int rc;
int size, cur_size;
- if (eip == fc->end) {
+ if (ctxt->_eip == fc->end) {
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;
- 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);
if (rc != X86EMUL_CONTINUE)
return rc;
@@ -672,20 +680,21 @@ static int do_insn_fetch_byte(struct x86_emulate_ctxt *ctxt,
return rc;
fc->end += size;
}
- *dest = fc->data[eip - fc->start];
+ *dest = fc->data[ctxt->_eip - fc->start];
+ ctxt->_eip++;
return X86EMUL_CONTINUE;
}
static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
- unsigned long eip, void *dest, unsigned size)
+ void *dest, unsigned size)
{
int rc;
/* x86 instructions are limited to 15 bytes. */
- if (eip + size - ctxt->eip > 15)
+ if (ctxt->_eip + size - ctxt->eip > 15)
return X86EMUL_UNHANDLEABLE;
while (size--) {
- rc = do_insn_fetch_byte(ctxt, eip++, dest++);
+ rc = do_insn_fetch_byte(ctxt, dest++);
if (rc != X86EMUL_CONTINUE)
return rc;
}
@@ -693,20 +702,18 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
}
/* Fetch next part of the instruction being emulated. */
-#define insn_fetch(_type, _size, _eip) \
+#define insn_fetch(_type, _size, _ctxt) \
({ unsigned long _x; \
- rc = do_insn_fetch(ctxt, (_eip), &_x, (_size)); \
+ rc = do_insn_fetch(_ctxt, &_x, (_size)); \
if (rc != X86EMUL_CONTINUE) \
goto done; \
- (_eip) += (_size); \
(_type)_x; \
})
-#define insn_fetch_arr(_arr, _size, _eip) \
-({ rc = do_insn_fetch(ctxt, (_eip), _arr, (_size)); \
+#define insn_fetch_arr(_arr, _size, _ctxt) \
+({ rc = do_insn_fetch(_ctxt, _arr, (_size)); \
if (rc != X86EMUL_CONTINUE) \
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 = insn_fetch(u8, 1, ctxt->_eip);
+ ctxt->modrm = insn_fetch(u8, 1, ctxt);
ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6;
ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3;
ctxt->modrm_rm |= (ctxt->modrm & 0x07);
@@ -928,13 +935,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) {
case 0:
if (ctxt->modrm_rm == 6)
- modrm_ea += insn_fetch(u16, 2, ctxt->_eip);
+ modrm_ea += insn_fetch(u16, 2, ctxt);
break;
case 1:
- modrm_ea += insn_fetch(s8, 1, ctxt->_eip);
+ modrm_ea += insn_fetch(s8, 1, ctxt);
break;
case 2:
- modrm_ea += insn_fetch(u16, 2, ctxt->_eip);
+ modrm_ea += insn_fetch(u16, 2, ctxt);
break;
}
switch (ctxt->modrm_rm) {
@@ -971,13 +978,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
} else {
/* 32/64-bit ModR/M decode. */
if ((ctxt->modrm_rm & 7) == 4) {
- sib = insn_fetch(u8, 1, ctxt->_eip);
+ sib = insn_fetch(u8, 1, ctxt);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
scale = sib >> 6;
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
modrm_ea += ctxt->regs[base_reg];
if (index_reg != 4)
@@ -990,13 +997,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) {
case 0:
if (ctxt->modrm_rm == 5)
- modrm_ea += insn_fetch(s32, 4, ctxt->_eip);
+ modrm_ea += insn_fetch(s32, 4, ctxt);
break;
case 1:
- modrm_ea += insn_fetch(s8, 1, ctxt->_eip);
+ modrm_ea += insn_fetch(s8, 1, ctxt);
break;
case 2:
- modrm_ea += insn_fetch(s32, 4, ctxt->_eip);
+ modrm_ea += insn_fetch(s32, 4, ctxt);
break;
}
}
@@ -1013,13 +1020,13 @@ static int decode_abs(struct x86_emulate_ctxt *ctxt,
op->type = OP_MEM;
switch (ctxt->ad_bytes) {
case 2:
- op->addr.mem.ea = insn_fetch(u16, 2, ctxt->_eip);
+ op->addr.mem.ea = insn_fetch(u16, 2, ctxt);
break;
case 4:
- op->addr.mem.ea = insn_fetch(u32, 4, ctxt->_eip);
+ op->addr.mem.ea = insn_fetch(u32, 4, ctxt);
break;
case 8:
- op->addr.mem.ea = insn_fetch(u64, 8, ctxt->_eip);
+ op->addr.mem.ea = insn_fetch(u64, 8, ctxt);
break;
}
done:
@@ -3309,13 +3316,13 @@ static int decode_imm(struct x86_emulate_ctxt *ctxt, struct operand *op,
/* NB. Immediates are sign-extended as necessary. */
switch (op->bytes) {
case 1:
- op->val = insn_fetch(s8, 1, ctxt->_eip);
+ op->val = insn_fetch(s8, 1, ctxt);
break;
case 2:
- op->val = insn_fetch(s16, 2, ctxt->_eip);
+ op->val = insn_fetch(s16, 2, ctxt);
break;
case 4:
- op->val = insn_fetch(s32, 4, ctxt->_eip);
+ op->val = insn_fetch(s32, 4, ctxt);
break;
}
if (!sign_extension) {
@@ -3374,7 +3381,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
/* Legacy prefixes. */
for (;;) {
- switch (ctxt->b = insn_fetch(u8, 1, ctxt->_eip)) {
+ switch (ctxt->b = insn_fetch(u8, 1, ctxt)) {
case 0x66: /* operand-size override */
op_prefix = true;
/* switch between 2/4 bytes */
@@ -3430,7 +3437,7 @@ done_prefixes:
/* Two-byte opcode? */
if (ctxt->b == 0x0f) {
ctxt->twobyte = 1;
- ctxt->b = insn_fetch(u8, 1, ctxt->_eip);
+ ctxt->b = insn_fetch(u8, 1, ctxt);
opcode = twobyte_table[ctxt->b];
}
ctxt->d = opcode.flags;
@@ -3438,13 +3445,13 @@ done_prefixes:
while (ctxt->d & GroupMask) {
switch (ctxt->d & GroupMask) {
case Group:
- ctxt->modrm = insn_fetch(u8, 1, ctxt->_eip);
+ ctxt->modrm = insn_fetch(u8, 1, ctxt);
--ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7;
opcode = opcode.u.group[goffset];
break;
case GroupDual:
- ctxt->modrm = insn_fetch(u8, 1, ctxt->_eip);
+ ctxt->modrm = insn_fetch(u8, 1, ctxt);
--ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7;
if ((ctxt->modrm >> 6) == 3)
@@ -3577,7 +3584,7 @@ done_prefixes:
ctxt->src.type = OP_IMM;
ctxt->src.addr.mem.ea = ctxt->_eip;
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;
case SrcMemFAddr:
memop.bytes = ctxt->op_bytes + 2;
@@ -3630,7 +3637,7 @@ done_prefixes:
ctxt->dst.type = OP_IMM;
ctxt->dst.addr.mem.ea = ctxt->_eip;
ctxt->dst.bytes = 1;
- ctxt->dst.val = insn_fetch(u8, 1, ctxt->_eip);
+ ctxt->dst.val = insn_fetch(u8, 1, ctxt);
break;
case DstMem:
case DstMem64:
--
1.7.4.1
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH 2/4] KVM: x86 emulator: Drop _size argument from insn_fetch()
2011-07-30 8:58 [PATCH 0/4] KVM: x86 emulator: Clean up decoder a bit Takuya Yoshikawa
2011-07-30 9:00 ` [PATCH 1/4] KVM: x86 emulator: Use ctxt->_eip directly in do_insn_fetch_byte() Takuya Yoshikawa
@ 2011-07-30 9:01 ` Takuya Yoshikawa
2011-07-30 9:02 ` [PATCH 3/4] KVM: x86 emulator: Let compiler know insn_fetch() rarely fails Takuya Yoshikawa
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Takuya Yoshikawa @ 2011-07-30 9:01 UTC (permalink / raw)
To: avi, mtosatti; +Cc: kvm, yoshikawa.takuya
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
_type is enough to know the size.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
---
arch/x86/kvm/emulate.c | 44 ++++++++++++++++++++++----------------------
1 files changed, 22 insertions(+), 22 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index fbb2e3a..54f26d9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -702,9 +702,9 @@ static int do_insn_fetch(struct x86_emulate_ctxt *ctxt,
}
/* Fetch next part of the instruction being emulated. */
-#define insn_fetch(_type, _size, _ctxt) \
+#define insn_fetch(_type, _ctxt) \
({ unsigned long _x; \
- rc = do_insn_fetch(_ctxt, &_x, (_size)); \
+ rc = do_insn_fetch(_ctxt, &_x, sizeof(_type)); \
if (rc != X86EMUL_CONTINUE) \
goto done; \
(_type)_x; \
@@ -901,7 +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 = insn_fetch(u8, 1, ctxt);
+ ctxt->modrm = insn_fetch(u8, ctxt);
ctxt->modrm_mod |= (ctxt->modrm & 0xc0) >> 6;
ctxt->modrm_reg |= (ctxt->modrm & 0x38) >> 3;
ctxt->modrm_rm |= (ctxt->modrm & 0x07);
@@ -935,13 +935,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) {
case 0:
if (ctxt->modrm_rm == 6)
- modrm_ea += insn_fetch(u16, 2, ctxt);
+ modrm_ea += insn_fetch(u16, ctxt);
break;
case 1:
- modrm_ea += insn_fetch(s8, 1, ctxt);
+ modrm_ea += insn_fetch(s8, ctxt);
break;
case 2:
- modrm_ea += insn_fetch(u16, 2, ctxt);
+ modrm_ea += insn_fetch(u16, ctxt);
break;
}
switch (ctxt->modrm_rm) {
@@ -978,13 +978,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
} else {
/* 32/64-bit ModR/M decode. */
if ((ctxt->modrm_rm & 7) == 4) {
- sib = insn_fetch(u8, 1, ctxt);
+ sib = insn_fetch(u8, ctxt);
index_reg |= (sib >> 3) & 7;
base_reg |= sib & 7;
scale = sib >> 6;
if ((base_reg & 7) == 5 && ctxt->modrm_mod == 0)
- modrm_ea += insn_fetch(s32, 4, ctxt);
+ modrm_ea += insn_fetch(s32, ctxt);
else
modrm_ea += ctxt->regs[base_reg];
if (index_reg != 4)
@@ -997,13 +997,13 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
switch (ctxt->modrm_mod) {
case 0:
if (ctxt->modrm_rm == 5)
- modrm_ea += insn_fetch(s32, 4, ctxt);
+ modrm_ea += insn_fetch(s32, ctxt);
break;
case 1:
- modrm_ea += insn_fetch(s8, 1, ctxt);
+ modrm_ea += insn_fetch(s8, ctxt);
break;
case 2:
- modrm_ea += insn_fetch(s32, 4, ctxt);
+ modrm_ea += insn_fetch(s32, ctxt);
break;
}
}
@@ -1020,13 +1020,13 @@ static int decode_abs(struct x86_emulate_ctxt *ctxt,
op->type = OP_MEM;
switch (ctxt->ad_bytes) {
case 2:
- op->addr.mem.ea = insn_fetch(u16, 2, ctxt);
+ op->addr.mem.ea = insn_fetch(u16, ctxt);
break;
case 4:
- op->addr.mem.ea = insn_fetch(u32, 4, ctxt);
+ op->addr.mem.ea = insn_fetch(u32, ctxt);
break;
case 8:
- op->addr.mem.ea = insn_fetch(u64, 8, ctxt);
+ op->addr.mem.ea = insn_fetch(u64, ctxt);
break;
}
done:
@@ -3316,13 +3316,13 @@ static int decode_imm(struct x86_emulate_ctxt *ctxt, struct operand *op,
/* NB. Immediates are sign-extended as necessary. */
switch (op->bytes) {
case 1:
- op->val = insn_fetch(s8, 1, ctxt);
+ op->val = insn_fetch(s8, ctxt);
break;
case 2:
- op->val = insn_fetch(s16, 2, ctxt);
+ op->val = insn_fetch(s16, ctxt);
break;
case 4:
- op->val = insn_fetch(s32, 4, ctxt);
+ op->val = insn_fetch(s32, ctxt);
break;
}
if (!sign_extension) {
@@ -3381,7 +3381,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len)
/* Legacy prefixes. */
for (;;) {
- switch (ctxt->b = insn_fetch(u8, 1, ctxt)) {
+ switch (ctxt->b = insn_fetch(u8, ctxt)) {
case 0x66: /* operand-size override */
op_prefix = true;
/* switch between 2/4 bytes */
@@ -3437,7 +3437,7 @@ done_prefixes:
/* Two-byte opcode? */
if (ctxt->b == 0x0f) {
ctxt->twobyte = 1;
- ctxt->b = insn_fetch(u8, 1, ctxt);
+ ctxt->b = insn_fetch(u8, ctxt);
opcode = twobyte_table[ctxt->b];
}
ctxt->d = opcode.flags;
@@ -3445,13 +3445,13 @@ done_prefixes:
while (ctxt->d & GroupMask) {
switch (ctxt->d & GroupMask) {
case Group:
- ctxt->modrm = insn_fetch(u8, 1, ctxt);
+ ctxt->modrm = insn_fetch(u8, ctxt);
--ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7;
opcode = opcode.u.group[goffset];
break;
case GroupDual:
- ctxt->modrm = insn_fetch(u8, 1, ctxt);
+ ctxt->modrm = insn_fetch(u8, ctxt);
--ctxt->_eip;
goffset = (ctxt->modrm >> 3) & 7;
if ((ctxt->modrm >> 6) == 3)
@@ -3637,7 +3637,7 @@ done_prefixes:
ctxt->dst.type = OP_IMM;
ctxt->dst.addr.mem.ea = ctxt->_eip;
ctxt->dst.bytes = 1;
- ctxt->dst.val = insn_fetch(u8, 1, ctxt);
+ ctxt->dst.val = insn_fetch(u8, ctxt);
break;
case DstMem:
case DstMem64:
--
1.7.4.1
^ permalink raw reply related [flat|nested] 8+ messages in thread