From b4e1af8961bf9b0d415abdf3e4908168daea6059 Mon Sep 17 00:00:00 2001 From: Roman Bolshakov Date: Thu, 18 Oct 2018 16:44:01 +0300 Subject: [PATCH] i386: hvf: Fix register refs if REX is present According to Intel(R)64 and IA-32 Architectures Software Developer's Manual, the following one-byte registers should be fetched when REX prefix is present (sorted by reg encoding index): AL, CL, DL, BL, SPL, BPL, SIL, DIL, R8L - R15L The first 8 are fetched if REX.R is zero, the last 8 if non-zero. The following registers should be fetched for instructions without REX prefix (also sorted by reg encoding index): AL, CL, DL, BL, AH, CH, DH, BH Current emulation code doesn't handle accesses to SPL, BPL, SIL, DIL when REX is present, thefore an instruction 40883e "mov %dil,(%rsi)" is decoded as "mov %bh,(%rsi)". That caused an infinite loop in vp_reset: https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg03293.html Signed-off-by: Roman Bolshakov Message-Id: <20181018134401.44471-1-r.bolshakov@yadro.com> Signed-off-by: Paolo Bonzini --- target/i386/hvf/x86_decode.c | 67 +++++++++++++++++++++++++------------------- target/i386/hvf/x86_decode.h | 6 ++-- 2 files changed, 42 insertions(+), 31 deletions(-) diff --git a/target/i386/hvf/x86_decode.c b/target/i386/hvf/x86_decode.c index 2d7540fe7c..2e33b69541 100644 --- a/target/i386/hvf/x86_decode.c +++ b/target/i386/hvf/x86_decode.c @@ -113,7 +113,8 @@ static void decode_modrm_reg(CPUX86State *env, struct x86_decode *decode, { op->type = X86_VAR_REG; op->reg = decode->modrm.reg; - op->ptr = get_reg_ref(env, op->reg, decode->rex.r, decode->operand_size); + op->ptr = get_reg_ref(env, op->reg, decode->rex.rex, decode->rex.r, + decode->operand_size); } static void decode_rax(CPUX86State *env, struct x86_decode *decode, @@ -121,7 +122,8 @@ static void decode_rax(CPUX86State *env, struct x86_decode *decode, { op->type = X86_VAR_REG; op->reg = R_EAX; - op->ptr = get_reg_ref(env, op->reg, 0, decode->operand_size); + op->ptr = get_reg_ref(env, op->reg, decode->rex.rex, 0, + decode->operand_size); } static inline void decode_immediate(CPUX86State *env, struct x86_decode *decode, @@ -263,16 +265,16 @@ static void decode_incgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0x40; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_decgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0x48; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_incgroup2(CPUX86State *env, struct x86_decode *decode) @@ -288,16 +290,16 @@ static void decode_pushgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0x50; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_popgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0x58; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_jxx(CPUX86State *env, struct x86_decode *decode) @@ -378,16 +380,16 @@ static void decode_xchgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0x90; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_movgroup(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0xb8; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); decode_immediate(env, decode, &decode->op[1], decode->operand_size); } @@ -402,8 +404,8 @@ static void decode_movgroup8(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[0] - 0xb0; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); decode_immediate(env, decode, &decode->op[1], decode->operand_size); } @@ -412,7 +414,8 @@ static void decode_rcx(CPUX86State *env, struct x86_decode *decode, { op->type = X86_VAR_REG; op->reg = R_ECX; - op->ptr = get_reg_ref(env, op->reg, decode->rex.b, decode->operand_size); + op->ptr = get_reg_ref(env, op->reg, decode->rex.rex, decode->rex.b, + decode->operand_size); } struct decode_tbl { @@ -639,8 +642,8 @@ static void decode_bswap(CPUX86State *env, struct x86_decode *decode) { decode->op[0].type = X86_VAR_REG; decode->op[0].reg = decode->opcode[1] - 0xc8; - decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.b, - decode->operand_size); + decode->op[0].ptr = get_reg_ref(env, decode->op[0].reg, decode->rex.rex, + decode->rex.b, decode->operand_size); } static void decode_d9_4(CPUX86State *env, struct x86_decode *decode) @@ -1686,7 +1689,8 @@ calc_addr: } } -target_ulong get_reg_ref(CPUX86State *env, int reg, int is_extended, int size) +target_ulong get_reg_ref(CPUX86State *env, int reg, int rex, int is_extended, + int size) { target_ulong ptr = 0; int which = 0; @@ -1698,7 +1702,7 @@ target_ulong get_reg_ref(CPUX86State *env, int reg, int is_extended, int size) switch (size) { case 1: - if (is_extended || reg < 4) { + if (is_extended || reg < 4 || rex) { which = 1; ptr = (target_ulong)&RL(env, reg); } else { @@ -1714,10 +1718,11 @@ target_ulong get_reg_ref(CPUX86State *env, int reg, int is_extended, int size) return ptr; } -target_ulong get_reg_val(CPUX86State *env, int reg, int is_extended, int size) +target_ulong get_reg_val(CPUX86State *env, int reg, int rex, int is_extended, + int size) { target_ulong val = 0; - memcpy(&val, (void *)get_reg_ref(env, reg, is_extended, size), size); + memcpy(&val, (void *)get_reg_ref(env, reg, rex, is_extended, size), size); return val; } @@ -1739,7 +1744,8 @@ static target_ulong get_sib_val(CPUX86State *env, struct x86_decode *decode, if (base_reg == R_ESP || base_reg == R_EBP) { *sel = R_SS; } - base = get_reg_val(env, decode->sib.base, decode->rex.b, addr_size); + base = get_reg_val(env, decode->sib.base, decode->rex.rex, + decode->rex.b, addr_size); } if (decode->rex.x) { @@ -1747,7 +1753,8 @@ static target_ulong get_sib_val(CPUX86State *env, struct x86_decode *decode, } if (index_reg != R_ESP) { - scaled_index = get_reg_val(env, index_reg, decode->rex.x, addr_size) << + scaled_index = get_reg_val(env, index_reg, decode->rex.rex, + decode->rex.x, addr_size) << decode->sib.scale; } return base + scaled_index; @@ -1776,7 +1783,8 @@ void calc_modrm_operand32(CPUX86State *env, struct x86_decode *decode, if (decode->modrm.rm == R_EBP || decode->modrm.rm == R_ESP) { seg = R_SS; } - ptr += get_reg_val(env, decode->modrm.rm, decode->rex.b, addr_size); + ptr += get_reg_val(env, decode->modrm.rm, decode->rex.rex, + decode->rex.b, addr_size); } if (X86_DECODE_CMD_LEA == decode->cmd) { @@ -1805,7 +1813,8 @@ void calc_modrm_operand64(CPUX86State *env, struct x86_decode *decode, } else if (0 == mod && 5 == rm) { ptr = RIP(env) + decode->len + (int32_t) offset; } else { - ptr = get_reg_val(env, src, decode->rex.b, 8) + (int64_t) offset; + ptr = get_reg_val(env, src, decode->rex.rex, decode->rex.b, 8) + + (int64_t) offset; } if (X86_DECODE_CMD_LEA == decode->cmd) { @@ -1822,8 +1831,8 @@ void calc_modrm_operand(CPUX86State *env, struct x86_decode *decode, if (3 == decode->modrm.mod) { op->reg = decode->modrm.reg; op->type = X86_VAR_REG; - op->ptr = get_reg_ref(env, decode->modrm.rm, decode->rex.b, - decode->operand_size); + op->ptr = get_reg_ref(env, decode->modrm.rm, decode->rex.rex, + decode->rex.b, decode->operand_size); return; } diff --git a/target/i386/hvf/x86_decode.h b/target/i386/hvf/x86_decode.h index 5ab6f31fa5..ef4bcab310 100644 --- a/target/i386/hvf/x86_decode.h +++ b/target/i386/hvf/x86_decode.h @@ -303,8 +303,10 @@ uint64_t sign(uint64_t val, int size); uint32_t decode_instruction(CPUX86State *env, struct x86_decode *decode); -target_ulong get_reg_ref(CPUX86State *env, int reg, int is_extended, int size); -target_ulong get_reg_val(CPUX86State *env, int reg, int is_extended, int size); +target_ulong get_reg_ref(CPUX86State *env, int reg, int rex, int is_extended, + int size); +target_ulong get_reg_val(CPUX86State *env, int reg, int rex, int is_extended, + int size); void calc_modrm_operand(CPUX86State *env, struct x86_decode *decode, struct x86_decode_op *op); target_ulong decode_linear_addr(CPUX86State *env, struct x86_decode *decode, -- 2.11.4.GIT