diff --git a/qemu/target-i386/bpt_helper.c b/qemu/target-i386/bpt_helper.c index dcc79dd1..205f580f 100644 --- a/qemu/target-i386/bpt_helper.c +++ b/qemu/target-i386/bpt_helper.c @@ -243,6 +243,13 @@ void helper_single_step(CPUX86State *env) raise_exception(env, EXCP01_DB); } +void helper_rechecking_single_step(CPUX86State *env) +{ + if ((env->eflags & TF_MASK) != 0) { + helper_single_step(env); + } +} + void helper_set_dr(CPUX86State *env, int reg, target_ulong t0) { #ifndef CONFIG_USER_ONLY diff --git a/qemu/target-i386/helper.h b/qemu/target-i386/helper.h index e88b75e1..d4aa441d 100644 --- a/qemu/target-i386/helper.h +++ b/qemu/target-i386/helper.h @@ -81,6 +81,7 @@ DEF_HELPER_2(cmpxchg16b_unlocked, void, env, tl) DEF_HELPER_2(cmpxchg16b, void, env, tl) #endif DEF_HELPER_1(single_step, void, env) +DEF_HELPER_1(rechecking_single_step, void, env) DEF_HELPER_1(cpuid, void, env) DEF_HELPER_1(rdtsc, void, env) DEF_HELPER_1(rdtscp, void, env) diff --git a/qemu/target-i386/translate.c b/qemu/target-i386/translate.c index 65048418..c7ae8984 100644 --- a/qemu/target-i386/translate.c +++ b/qemu/target-i386/translate.c @@ -2837,8 +2837,10 @@ static void gen_bnd_jmp(DisasContext *s) } /* Generate an end of block. Trace exception is also generated if needed. - If IIM, set HF_INHIBIT_IRQ_MASK if it isn't already set. */ -static void gen_eob_inhibit_irq(DisasContext *s, bool inhibit) + If INHIBIT, set HF_INHIBIT_IRQ_MASK if it isn't already set. + If RECHECK_TF, emit a rechecking helper for #DB, ignoring the state of + S->TF. This is used by the syscall/sysret insns. */ +static void gen_eob_worker(DisasContext *s, bool inhibit, bool recheck_tf) { TCGContext *tcg_ctx = s->uc->tcg_ctx; @@ -2856,18 +2858,28 @@ static void gen_eob_inhibit_irq(DisasContext *s, bool inhibit) } if (s->singlestep_enabled) { gen_helper_debug(tcg_ctx, tcg_ctx->cpu_env); + } else if (recheck_tf) { + gen_helper_rechecking_single_step(tcg_ctx, tcg_ctx->cpu_env); + tcg_gen_exit_tb(tcg_ctx, 0); } else if (s->tf) { gen_helper_single_step(tcg_ctx, tcg_ctx->cpu_env); } else { - tcg_gen_exit_tb(s->uc->tcg_ctx, 0); + tcg_gen_exit_tb(tcg_ctx, 0); } s->is_jmp = DISAS_TB_JUMP; } +/* End of block. + If INHIBIT, set HF_INHIBIT_IRQ_MASK if it isn't already set. */ +static void gen_eob_inhibit_irq(DisasContext *s, bool inhibit) +{ + gen_eob_worker(s, inhibit, false); +} + /* End of block, resetting the inhibit irq flag. */ static void gen_eob(DisasContext *s) { - gen_eob_inhibit_irq(s, false); + gen_eob_worker(s, false, false); } /* generate a jump to eip. No segment change must happen before as a @@ -7089,7 +7101,10 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, tcg_const_i32(tcg_ctx, s->pc - s->cs_base)); set_cc_op(s, CC_OP_EFLAGS); } - gen_eob(s); + /* TF handling for the syscall insn is different. The TF bit is checked + after the syscall insn completes. This allows #DB to not be + generated after one has entered CPL0 if TF is set in FMASK. */ + gen_eob_worker(s, false, true); break; case 0xe8: /* call im */ { @@ -7797,7 +7812,11 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, if (s->lma) { set_cc_op(s, CC_OP_EFLAGS); } - gen_eob(s); + /* TF handling for the sysret insn is different. The TF bit is + checked after the sysret insn completes. This allows #DB to be + generated "as if" the syscall insn in userspace has just + completed. */ + gen_eob_worker(s, false, true); } break; #endif