From c2ffd7549b14373e9ca68eccd84fab141ffde646 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 19 Jul 2021 10:43:46 -1000 Subject: [PATCH] accel/tcg: Record singlestep_enabled in tb->cflags MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Set CF_SINGLE_STEP when single-stepping is enabled. This avoids the need to flush all tb's when turning single-stepping on or off. Tested-by: Mark Cave-Ayland Reviewed-by: Alex Bennée Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- accel/tcg/cpu-exec.c | 7 ++++++- accel/tcg/translate-all.c | 4 ---- accel/tcg/translator.c | 7 +------ cpu.c | 4 ---- include/exec/exec-all.h | 1 + 5 files changed, 8 insertions(+), 15 deletions(-) diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 5cc6363f4c..fc895cf51e 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -150,10 +150,15 @@ uint32_t curr_cflags(CPUState *cpu) uint32_t cflags = cpu->tcg_cflags; /* + * Record gdb single-step. We should be exiting the TB by raising + * EXCP_DEBUG, but to simplify other tests, disable chaining too. + * * For singlestep and -d nochain, suppress goto_tb so that * we can log -d cpu,exec after every TB. */ - if (singlestep) { + if (unlikely(cpu->singlestep_enabled)) { + cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | CF_SINGLE_STEP | 1; + } else if (singlestep) { cflags |= CF_NO_GOTO_TB | 1; } else if (qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) { cflags |= CF_NO_GOTO_TB; diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index bf82c15aab..bbfcfb698c 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1432,10 +1432,6 @@ TranslationBlock *tb_gen_code(CPUState *cpu, } QEMU_BUILD_BUG_ON(CF_COUNT_MASK + 1 != TCG_MAX_INSNS); - if (cpu->singlestep_enabled) { - max_insns = 1; - } - buffer_overflow: tb = tcg_tb_alloc(tcg_ctx); if (unlikely(!tb)) { diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c index b45337f3ba..c53a7f8e44 100644 --- a/accel/tcg/translator.c +++ b/accel/tcg/translator.c @@ -38,11 +38,6 @@ bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest) return false; } - /* Suppress goto_tb in the case of single-steping. */ - if (db->singlestep_enabled) { - return false; - } - /* Check for the dest on the same page as the start of the TB. */ return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0; } @@ -60,7 +55,7 @@ void translator_loop(const TranslatorOps *ops, DisasContextBase *db, db->is_jmp = DISAS_NEXT; db->num_insns = 0; db->max_insns = max_insns; - db->singlestep_enabled = cpu->singlestep_enabled; + db->singlestep_enabled = cflags & CF_SINGLE_STEP; ops->init_disas_context(db, cpu); tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ diff --git a/cpu.c b/cpu.c index d6ae5ae581..e1799a15bc 100644 --- a/cpu.c +++ b/cpu.c @@ -326,10 +326,6 @@ void cpu_single_step(CPUState *cpu, int enabled) cpu->singlestep_enabled = enabled; if (kvm_enabled()) { kvm_update_guest_debug(cpu, 0); - } else { - /* must flush all the translated code to avoid inconsistencies */ - /* XXX: only flush what is necessary */ - tb_flush(cpu); } trace_breakpoint_singlestep(cpu->cpu_index, enabled); } diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index 6873cce8df..5d1b6d80fb 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -497,6 +497,7 @@ struct TranslationBlock { #define CF_COUNT_MASK 0x000001ff #define CF_NO_GOTO_TB 0x00000200 /* Do not chain with goto_tb */ #define CF_NO_GOTO_PTR 0x00000400 /* Do not chain with goto_ptr */ +#define CF_SINGLE_STEP 0x00000800 /* gdbstub single-step in effect */ #define CF_LAST_IO 0x00008000 /* Last insn may be an IO access. */ #define CF_MEMI_ONLY 0x00010000 /* Only instrument memory ops */ #define CF_USE_ICOUNT 0x00020000 -- 2.11.4.GIT