From 807941b121cf77e70eec8db308b8c1f496cc79e9 Mon Sep 17 00:00:00 2001 From: Takuya Yoshikawa Date: Sat, 30 Jul 2011 18:00:17 +0900 Subject: [PATCH] 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 Signed-off-by: Avi Kivity --- arch/x86/kvm/emulate.c | 79 +++++++++++++++++++++++++++----------------------- 1 file changed, 43 insertions(+), 36 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 8b4cc5f..ce48dc4 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: -- 2.7.4