| Message ID | 20231110170831.185001-1-richard.henderson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [for-8.2] accel/tcg: Remove CF_LAST_IO | expand |
Tested-by: Clément Chigot <chigot@adacore.com> On Fri, Nov 10, 2023 at 6:08 PM Richard Henderson <richard.henderson@linaro.org> wrote: > > In cpu_exec_step_atomic, we did not set CF_LAST_IO, which can > lead to a loop with cpu_io_recompile. > > But since 18a536f1f8 ("Always require can_do_io") we no longer need > a flag to indicate when the last insn should have can_do_io set, so > remove the flag entirely. > > Reported-by: Clément Chigot <chigot@adacore.com> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1961 > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > docs/devel/tcg-icount.rst | 6 ------ > include/exec/translation-block.h | 13 ++++++------- > accel/tcg/cpu-exec.c | 2 +- > accel/tcg/tb-maint.c | 6 ++---- > accel/tcg/translate-all.c | 4 ++-- > accel/tcg/translator.c | 22 +++++++++------------- > system/watchpoint.c | 6 ++---- > 7 files changed, 22 insertions(+), 37 deletions(-) > > diff --git a/docs/devel/tcg-icount.rst b/docs/devel/tcg-icount.rst > index 50c8e8dabc..7df883446a 100644 > --- a/docs/devel/tcg-icount.rst > +++ b/docs/devel/tcg-icount.rst > @@ -62,12 +62,6 @@ To deal with this case, when an I/O access is made we: > - re-compile a single [1]_ instruction block for the current PC > - exit the cpu loop and execute the re-compiled block > > -The new block is created with the CF_LAST_IO compile flag which > -ensures the final instruction translation starts with a call to > -gen_io_start() so we don't enter a perpetual loop constantly > -recompiling a single instruction block. For translators using the > -common translator_loop this is done automatically. > - > .. [1] sometimes two instructions if dealing with delay slots > > Other I/O operations > diff --git a/include/exec/translation-block.h b/include/exec/translation-block.h > index b785751774..e2b26e16da 100644 > --- a/include/exec/translation-block.h > +++ b/include/exec/translation-block.h > @@ -71,13 +71,12 @@ struct TranslationBlock { > #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 > -#define CF_INVALID 0x00040000 /* TB is stale. Set with @jmp_lock held */ > -#define CF_PARALLEL 0x00080000 /* Generate code for a parallel context */ > -#define CF_NOIRQ 0x00100000 /* Generate an uninterruptible TB */ > -#define CF_PCREL 0x00200000 /* Opcodes in TB are PC-relative */ > +#define CF_MEMI_ONLY 0x00001000 /* Only instrument memory ops */ > +#define CF_USE_ICOUNT 0x00002000 > +#define CF_INVALID 0x00004000 /* TB is stale. Set with @jmp_lock held */ > +#define CF_PARALLEL 0x00008000 /* Generate code for a parallel context */ > +#define CF_NOIRQ 0x00010000 /* Generate an uninterruptible TB */ > +#define CF_PCREL 0x00020000 /* Opcodes in TB are PC-relative */ > #define CF_CLUSTER_MASK 0xff000000 /* Top 8 bits are cluster ID */ > #define CF_CLUSTER_SHIFT 24 > > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c > index 1a5bc90220..c938eb96f8 100644 > --- a/accel/tcg/cpu-exec.c > +++ b/accel/tcg/cpu-exec.c > @@ -721,7 +721,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret) > && cpu->neg.icount_decr.u16.low + cpu->icount_extra == 0) { > /* Execute just one insn to trigger exception pending in the log */ > cpu->cflags_next_tb = (curr_cflags(cpu) & ~CF_USE_ICOUNT) > - | CF_LAST_IO | CF_NOIRQ | 1; > + | CF_NOIRQ | 1; > } > #endif > return false; > diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c > index e678d20dc2..3d2a896220 100644 > --- a/accel/tcg/tb-maint.c > +++ b/accel/tcg/tb-maint.c > @@ -1083,8 +1083,7 @@ bool tb_invalidate_phys_page_unwind(tb_page_addr_t addr, uintptr_t pc) > if (current_tb_modified) { > /* Force execution of one insn next time. */ > CPUState *cpu = current_cpu; > - cpu->cflags_next_tb = > - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); > return true; > } > return false; > @@ -1154,8 +1153,7 @@ tb_invalidate_phys_page_range__locked(struct page_collection *pages, > if (current_tb_modified) { > page_collection_unlock(pages); > /* Force execution of one insn next time. */ > - current_cpu->cflags_next_tb = > - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); > + current_cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); > mmap_unlock(); > cpu_loop_exit_noexc(current_cpu); > } > diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c > index b263857ecc..79a88f5fb7 100644 > --- a/accel/tcg/translate-all.c > +++ b/accel/tcg/translate-all.c > @@ -304,7 +304,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, > > if (phys_pc == -1) { > /* Generate a one-shot TB with 1 insn in it */ > - cflags = (cflags & ~CF_COUNT_MASK) | CF_LAST_IO | 1; > + cflags = (cflags & ~CF_COUNT_MASK) | 1; > } > > max_insns = cflags & CF_COUNT_MASK; > @@ -632,7 +632,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr) > * operations only (which execute after completion) so we don't > * double instrument the instruction. > */ > - cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | CF_LAST_IO | n; > + cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | n; > > if (qemu_loglevel_mask(CPU_LOG_EXEC)) { > vaddr pc = log_pc(cpu, tb); > diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c > index 575b9812ad..38c34009a5 100644 > --- a/accel/tcg/translator.c > +++ b/accel/tcg/translator.c > @@ -89,7 +89,7 @@ static TCGOp *gen_tb_start(DisasContextBase *db, uint32_t cflags) > * each translation block. The cost is minimal, plus it would be > * very easy to forget doing it in the translator. > */ > - set_can_do_io(db, db->max_insns == 1 && (cflags & CF_LAST_IO)); > + set_can_do_io(db, db->max_insns == 1); > > return icount_start_insn; > } > @@ -151,13 +151,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, > ops->tb_start(db, cpu); > tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ > > - if (cflags & CF_MEMI_ONLY) { > - /* We should only see CF_MEMI_ONLY for io_recompile. */ > - assert(cflags & CF_LAST_IO); > - plugin_enabled = plugin_gen_tb_start(cpu, db, true); > - } else { > - plugin_enabled = plugin_gen_tb_start(cpu, db, false); > - } > + plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY); > db->plugin_enabled = plugin_enabled; > > while (true) { > @@ -169,11 +163,13 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, > plugin_gen_insn_start(cpu, db); > } > > - /* Disassemble one instruction. The translate_insn hook should > - update db->pc_next and db->is_jmp to indicate what should be > - done next -- either exiting this loop or locate the start of > - the next instruction. */ > - if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) { > + /* > + * Disassemble one instruction. The translate_insn hook should > + * update db->pc_next and db->is_jmp to indicate what should be > + * done next -- either exiting this loop or locate the start of > + * the next instruction. > + */ > + if (db->num_insns == db->max_insns) { > /* Accept I/O on the last instruction. */ > set_can_do_io(db, true); > } > diff --git a/system/watchpoint.c b/system/watchpoint.c > index 45d1f12faf..ba5ad13352 100644 > --- a/system/watchpoint.c > +++ b/system/watchpoint.c > @@ -179,8 +179,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > */ > if (!cpu->neg.can_do_io) { > /* Force execution of one insn next time. */ > - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ > - | curr_cflags(cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); > cpu_loop_exit_restore(cpu, ra); > } > /* > @@ -212,8 +211,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > cpu_loop_exit(cpu); > } else { > /* Force execution of one insn next time. */ > - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ > - | curr_cflags(cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); > mmap_unlock(); > cpu_loop_exit_noexc(cpu); > } > -- > 2.34.1 >
Reviewed-by: Claudio Fontana <cfontana@suse.de> On 11/10/23 18:08, Richard Henderson wrote: > In cpu_exec_step_atomic, we did not set CF_LAST_IO, which can > lead to a loop with cpu_io_recompile. > > But since 18a536f1f8 ("Always require can_do_io") we no longer need > a flag to indicate when the last insn should have can_do_io set, so > remove the flag entirely. > > Reported-by: Clément Chigot <chigot@adacore.com> > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1961 > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > docs/devel/tcg-icount.rst | 6 ------ > include/exec/translation-block.h | 13 ++++++------- > accel/tcg/cpu-exec.c | 2 +- > accel/tcg/tb-maint.c | 6 ++---- > accel/tcg/translate-all.c | 4 ++-- > accel/tcg/translator.c | 22 +++++++++------------- > system/watchpoint.c | 6 ++---- > 7 files changed, 22 insertions(+), 37 deletions(-) > > diff --git a/docs/devel/tcg-icount.rst b/docs/devel/tcg-icount.rst > index 50c8e8dabc..7df883446a 100644 > --- a/docs/devel/tcg-icount.rst > +++ b/docs/devel/tcg-icount.rst > @@ -62,12 +62,6 @@ To deal with this case, when an I/O access is made we: > - re-compile a single [1]_ instruction block for the current PC > - exit the cpu loop and execute the re-compiled block > > -The new block is created with the CF_LAST_IO compile flag which > -ensures the final instruction translation starts with a call to > -gen_io_start() so we don't enter a perpetual loop constantly > -recompiling a single instruction block. For translators using the > -common translator_loop this is done automatically. > - > .. [1] sometimes two instructions if dealing with delay slots > > Other I/O operations > diff --git a/include/exec/translation-block.h b/include/exec/translation-block.h > index b785751774..e2b26e16da 100644 > --- a/include/exec/translation-block.h > +++ b/include/exec/translation-block.h > @@ -71,13 +71,12 @@ struct TranslationBlock { > #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 > -#define CF_INVALID 0x00040000 /* TB is stale. Set with @jmp_lock held */ > -#define CF_PARALLEL 0x00080000 /* Generate code for a parallel context */ > -#define CF_NOIRQ 0x00100000 /* Generate an uninterruptible TB */ > -#define CF_PCREL 0x00200000 /* Opcodes in TB are PC-relative */ > +#define CF_MEMI_ONLY 0x00001000 /* Only instrument memory ops */ > +#define CF_USE_ICOUNT 0x00002000 > +#define CF_INVALID 0x00004000 /* TB is stale. Set with @jmp_lock held */ > +#define CF_PARALLEL 0x00008000 /* Generate code for a parallel context */ > +#define CF_NOIRQ 0x00010000 /* Generate an uninterruptible TB */ > +#define CF_PCREL 0x00020000 /* Opcodes in TB are PC-relative */ > #define CF_CLUSTER_MASK 0xff000000 /* Top 8 bits are cluster ID */ > #define CF_CLUSTER_SHIFT 24 > > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c > index 1a5bc90220..c938eb96f8 100644 > --- a/accel/tcg/cpu-exec.c > +++ b/accel/tcg/cpu-exec.c > @@ -721,7 +721,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret) > && cpu->neg.icount_decr.u16.low + cpu->icount_extra == 0) { > /* Execute just one insn to trigger exception pending in the log */ > cpu->cflags_next_tb = (curr_cflags(cpu) & ~CF_USE_ICOUNT) > - | CF_LAST_IO | CF_NOIRQ | 1; > + | CF_NOIRQ | 1; > } > #endif > return false; > diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c > index e678d20dc2..3d2a896220 100644 > --- a/accel/tcg/tb-maint.c > +++ b/accel/tcg/tb-maint.c > @@ -1083,8 +1083,7 @@ bool tb_invalidate_phys_page_unwind(tb_page_addr_t addr, uintptr_t pc) > if (current_tb_modified) { > /* Force execution of one insn next time. */ > CPUState *cpu = current_cpu; > - cpu->cflags_next_tb = > - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); > return true; > } > return false; > @@ -1154,8 +1153,7 @@ tb_invalidate_phys_page_range__locked(struct page_collection *pages, > if (current_tb_modified) { > page_collection_unlock(pages); > /* Force execution of one insn next time. */ > - current_cpu->cflags_next_tb = > - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); > + current_cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); > mmap_unlock(); > cpu_loop_exit_noexc(current_cpu); > } > diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c > index b263857ecc..79a88f5fb7 100644 > --- a/accel/tcg/translate-all.c > +++ b/accel/tcg/translate-all.c > @@ -304,7 +304,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, > > if (phys_pc == -1) { > /* Generate a one-shot TB with 1 insn in it */ > - cflags = (cflags & ~CF_COUNT_MASK) | CF_LAST_IO | 1; > + cflags = (cflags & ~CF_COUNT_MASK) | 1; > } > > max_insns = cflags & CF_COUNT_MASK; > @@ -632,7 +632,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr) > * operations only (which execute after completion) so we don't > * double instrument the instruction. > */ > - cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | CF_LAST_IO | n; > + cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | n; > > if (qemu_loglevel_mask(CPU_LOG_EXEC)) { > vaddr pc = log_pc(cpu, tb); > diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c > index 575b9812ad..38c34009a5 100644 > --- a/accel/tcg/translator.c > +++ b/accel/tcg/translator.c > @@ -89,7 +89,7 @@ static TCGOp *gen_tb_start(DisasContextBase *db, uint32_t cflags) > * each translation block. The cost is minimal, plus it would be > * very easy to forget doing it in the translator. > */ > - set_can_do_io(db, db->max_insns == 1 && (cflags & CF_LAST_IO)); > + set_can_do_io(db, db->max_insns == 1); > > return icount_start_insn; > } > @@ -151,13 +151,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, > ops->tb_start(db, cpu); > tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ > > - if (cflags & CF_MEMI_ONLY) { > - /* We should only see CF_MEMI_ONLY for io_recompile. */ > - assert(cflags & CF_LAST_IO); > - plugin_enabled = plugin_gen_tb_start(cpu, db, true); > - } else { > - plugin_enabled = plugin_gen_tb_start(cpu, db, false); > - } > + plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY); > db->plugin_enabled = plugin_enabled; > > while (true) { > @@ -169,11 +163,13 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, > plugin_gen_insn_start(cpu, db); > } > > - /* Disassemble one instruction. The translate_insn hook should > - update db->pc_next and db->is_jmp to indicate what should be > - done next -- either exiting this loop or locate the start of > - the next instruction. */ > - if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) { > + /* > + * Disassemble one instruction. The translate_insn hook should > + * update db->pc_next and db->is_jmp to indicate what should be > + * done next -- either exiting this loop or locate the start of > + * the next instruction. > + */ > + if (db->num_insns == db->max_insns) { > /* Accept I/O on the last instruction. */ > set_can_do_io(db, true); > } > diff --git a/system/watchpoint.c b/system/watchpoint.c > index 45d1f12faf..ba5ad13352 100644 > --- a/system/watchpoint.c > +++ b/system/watchpoint.c > @@ -179,8 +179,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > */ > if (!cpu->neg.can_do_io) { > /* Force execution of one insn next time. */ > - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ > - | curr_cflags(cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); > cpu_loop_exit_restore(cpu, ra); > } > /* > @@ -212,8 +211,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, > cpu_loop_exit(cpu); > } else { > /* Force execution of one insn next time. */ > - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ > - | curr_cflags(cpu); > + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); > mmap_unlock(); > cpu_loop_exit_noexc(cpu); > }
diff --git a/docs/devel/tcg-icount.rst b/docs/devel/tcg-icount.rst index 50c8e8dabc..7df883446a 100644 --- a/docs/devel/tcg-icount.rst +++ b/docs/devel/tcg-icount.rst @@ -62,12 +62,6 @@ To deal with this case, when an I/O access is made we: - re-compile a single [1]_ instruction block for the current PC - exit the cpu loop and execute the re-compiled block -The new block is created with the CF_LAST_IO compile flag which -ensures the final instruction translation starts with a call to -gen_io_start() so we don't enter a perpetual loop constantly -recompiling a single instruction block. For translators using the -common translator_loop this is done automatically. - .. [1] sometimes two instructions if dealing with delay slots Other I/O operations diff --git a/include/exec/translation-block.h b/include/exec/translation-block.h index b785751774..e2b26e16da 100644 --- a/include/exec/translation-block.h +++ b/include/exec/translation-block.h @@ -71,13 +71,12 @@ struct TranslationBlock { #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 -#define CF_INVALID 0x00040000 /* TB is stale. Set with @jmp_lock held */ -#define CF_PARALLEL 0x00080000 /* Generate code for a parallel context */ -#define CF_NOIRQ 0x00100000 /* Generate an uninterruptible TB */ -#define CF_PCREL 0x00200000 /* Opcodes in TB are PC-relative */ +#define CF_MEMI_ONLY 0x00001000 /* Only instrument memory ops */ +#define CF_USE_ICOUNT 0x00002000 +#define CF_INVALID 0x00004000 /* TB is stale. Set with @jmp_lock held */ +#define CF_PARALLEL 0x00008000 /* Generate code for a parallel context */ +#define CF_NOIRQ 0x00010000 /* Generate an uninterruptible TB */ +#define CF_PCREL 0x00020000 /* Opcodes in TB are PC-relative */ #define CF_CLUSTER_MASK 0xff000000 /* Top 8 bits are cluster ID */ #define CF_CLUSTER_SHIFT 24 diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 1a5bc90220..c938eb96f8 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -721,7 +721,7 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret) && cpu->neg.icount_decr.u16.low + cpu->icount_extra == 0) { /* Execute just one insn to trigger exception pending in the log */ cpu->cflags_next_tb = (curr_cflags(cpu) & ~CF_USE_ICOUNT) - | CF_LAST_IO | CF_NOIRQ | 1; + | CF_NOIRQ | 1; } #endif return false; diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c index e678d20dc2..3d2a896220 100644 --- a/accel/tcg/tb-maint.c +++ b/accel/tcg/tb-maint.c @@ -1083,8 +1083,7 @@ bool tb_invalidate_phys_page_unwind(tb_page_addr_t addr, uintptr_t pc) if (current_tb_modified) { /* Force execution of one insn next time. */ CPUState *cpu = current_cpu; - cpu->cflags_next_tb = - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); return true; } return false; @@ -1154,8 +1153,7 @@ tb_invalidate_phys_page_range__locked(struct page_collection *pages, if (current_tb_modified) { page_collection_unlock(pages); /* Force execution of one insn next time. */ - current_cpu->cflags_next_tb = - 1 | CF_LAST_IO | CF_NOIRQ | curr_cflags(current_cpu); + current_cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(current_cpu); mmap_unlock(); cpu_loop_exit_noexc(current_cpu); } diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index b263857ecc..79a88f5fb7 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -304,7 +304,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, if (phys_pc == -1) { /* Generate a one-shot TB with 1 insn in it */ - cflags = (cflags & ~CF_COUNT_MASK) | CF_LAST_IO | 1; + cflags = (cflags & ~CF_COUNT_MASK) | 1; } max_insns = cflags & CF_COUNT_MASK; @@ -632,7 +632,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr) * operations only (which execute after completion) so we don't * double instrument the instruction. */ - cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | CF_LAST_IO | n; + cpu->cflags_next_tb = curr_cflags(cpu) | CF_MEMI_ONLY | n; if (qemu_loglevel_mask(CPU_LOG_EXEC)) { vaddr pc = log_pc(cpu, tb); diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c index 575b9812ad..38c34009a5 100644 --- a/accel/tcg/translator.c +++ b/accel/tcg/translator.c @@ -89,7 +89,7 @@ static TCGOp *gen_tb_start(DisasContextBase *db, uint32_t cflags) * each translation block. The cost is minimal, plus it would be * very easy to forget doing it in the translator. */ - set_can_do_io(db, db->max_insns == 1 && (cflags & CF_LAST_IO)); + set_can_do_io(db, db->max_insns == 1); return icount_start_insn; } @@ -151,13 +151,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, ops->tb_start(db, cpu); tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ - if (cflags & CF_MEMI_ONLY) { - /* We should only see CF_MEMI_ONLY for io_recompile. */ - assert(cflags & CF_LAST_IO); - plugin_enabled = plugin_gen_tb_start(cpu, db, true); - } else { - plugin_enabled = plugin_gen_tb_start(cpu, db, false); - } + plugin_enabled = plugin_gen_tb_start(cpu, db, cflags & CF_MEMI_ONLY); db->plugin_enabled = plugin_enabled; while (true) { @@ -169,11 +163,13 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, plugin_gen_insn_start(cpu, db); } - /* Disassemble one instruction. The translate_insn hook should - update db->pc_next and db->is_jmp to indicate what should be - done next -- either exiting this loop or locate the start of - the next instruction. */ - if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) { + /* + * Disassemble one instruction. The translate_insn hook should + * update db->pc_next and db->is_jmp to indicate what should be + * done next -- either exiting this loop or locate the start of + * the next instruction. + */ + if (db->num_insns == db->max_insns) { /* Accept I/O on the last instruction. */ set_can_do_io(db, true); } diff --git a/system/watchpoint.c b/system/watchpoint.c index 45d1f12faf..ba5ad13352 100644 --- a/system/watchpoint.c +++ b/system/watchpoint.c @@ -179,8 +179,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, */ if (!cpu->neg.can_do_io) { /* Force execution of one insn next time. */ - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ - | curr_cflags(cpu); + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); cpu_loop_exit_restore(cpu, ra); } /* @@ -212,8 +211,7 @@ void cpu_check_watchpoint(CPUState *cpu, vaddr addr, vaddr len, cpu_loop_exit(cpu); } else { /* Force execution of one insn next time. */ - cpu->cflags_next_tb = 1 | CF_LAST_IO | CF_NOIRQ - | curr_cflags(cpu); + cpu->cflags_next_tb = 1 | CF_NOIRQ | curr_cflags(cpu); mmap_unlock(); cpu_loop_exit_noexc(cpu); }
In cpu_exec_step_atomic, we did not set CF_LAST_IO, which can lead to a loop with cpu_io_recompile. But since 18a536f1f8 ("Always require can_do_io") we no longer need a flag to indicate when the last insn should have can_do_io set, so remove the flag entirely. Reported-by: Clément Chigot <chigot@adacore.com> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1961 Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- docs/devel/tcg-icount.rst | 6 ------ include/exec/translation-block.h | 13 ++++++------- accel/tcg/cpu-exec.c | 2 +- accel/tcg/tb-maint.c | 6 ++---- accel/tcg/translate-all.c | 4 ++-- accel/tcg/translator.c | 22 +++++++++------------- system/watchpoint.c | 6 ++---- 7 files changed, 22 insertions(+), 37 deletions(-)