[PATCH v3 00/10] Deprecate/rename singlestep command line option, monitor interfaces
The command line option '-singlestep' and its HMP equivalent the 'singlestep' command are very confusingly named, because they have nothing to do with single-stepping the guest (either via the gdb stub or by emulation of guest CPU architectural debug facilities). What they actually do is put TCG into a mode where it puts only one guest instruction into each translation block. This is useful for some circumstances such as when you want the -d debug logging to be easier to interpret, or if you have a finicky guest binary that wants to see interrupts delivered at something other than the end of a basic block. The confusing name is made worse by the fact that our documentation for these is so minimal as to be useless for telling users what they really do. This series: * changes the command line interface: for user-mode emulators, the new option is '-one-insn-per-tb', and for system mode emulators it is a TCG accel property '-accel tcg,one-insn-per-tb=on' * updates all the places which currently directly touch the 'singlestep' global variable to instead get the current accelerator and query/set the QOM property (except the one internal to TCG itself in curr_cflags()) * documents that the old -singlestep option is deprecated * adds a new HMP command 'one-insn-per-tb', and deprecates the old 'singlestep' command. (Strictly we don't need to deprecate HMP commands, but I'd already written the code for v1 of this series and it's a minor user convenience.) * moves the 'is one-insn-per-tb on?' info from 'info status' to 'info jit' * deprecates the 'singlestep' member of the QMP StatusInfo type, with no replacement. (We have a sketch of a design of how we might provide this in QMP if we need to, but I'm pretty sure nobody using QMP is actually using the info in the 'singlestep' field, especially since it's always been wrongly documented and there's no write interface, only a read one.) Changes v2->v3: * curr_cflags() is a hot path, so use a global variable so it doesn't have to fetch the current accelerator object. (NB: I haven't done the tcg_global_cflags thing suggested in review of v2; justification in the below-the-fold part of the patch 3 commit message notes.) * put the new line in test-hmp.c in its proper alphabetical order place in patch 8 * in patch 10 don't provide a replacement field in the QMP StatusInfo type, just deprecate the old one * I finally tested that bsd-user compiles, and fixed the missing-close-bracket error in that patch :-) Patches still needing review: 3, 7, 10 thanks -- PMM Peter Maydell (10): make one-insn-per-tb an accel option softmmu: Don't use 'singlestep' global in QMP and HMP commands accel/tcg: Use one_insn_per_tb global instead of old singlestep global linux-user: Add '-one-insn-per-tb' option equivalent to '-singlestep' bsd-user: Add '-one-insn-per-tb' option equivalent to '-singlestep' Document that -singlestep command line option is deprecated accel/tcg: Report one-insn-per-tb in 'info jit', not 'info status' hmp: Add 'one-insn-per-tb' command equivalent to 'singlestep' qapi/run-state.json: Fix missing newline at end of file hmp: Deprecate 'singlestep' member of StatusInfo docs/about/deprecated.rst | 39 +++++++++++++++++++++++++++++++++++++ docs/user/main.rst | 14 +++++++++++-- qapi/run-state.json | 16 +++++++++++---- accel/tcg/internal.h | 2 ++ include/exec/cpu-common.h | 2 -- include/monitor/hmp.h | 2 +- accel/tcg/cpu-exec.c | 2 +- accel/tcg/monitor.c | 14 +++++++++++++ accel/tcg/tcg-all.c | 23 ++++++++++++++++++++++ bsd-user/main.c | 14 ++++++++----- linux-user/main.c | 18 +++++++++++------ softmmu/globals.c | 1 - softmmu/runstate-hmp-cmds.c | 25 ++++++++++++++++++------ softmmu/runstate.c | 10 +++++++++- softmmu/vl.c | 17 ++++++++++++++-- tests/qtest/test-hmp.c | 1 + hmp-commands.hx | 25 ++++++++++++++++++++---- qemu-options.hx | 12 ++++++++++-- tcg/tci/README | 2 +- 19 files changed, 201 insertions(+), 38 deletions(-) -- 2.34.1
This commit adds 'one-insn-per-tb' as a property on the TCG accelerator object, so you can enable it with -accel tcg,one-insn-per-tb=on It has the same behaviour as the existing '-singlestep' command line option. We use a different name because 'singlestep' has always been a confusing choice, because it doesn't have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations (such as analysing debug logs). The existing '-singlestep' commandline options are decoupled from the global 'singlestep' variable and instead now are syntactic sugar for setting the accel property. (These can then go away after a deprecation period.) The global variable remains for the moment as: * what the TCG code looks at to change its behaviour * what HMP and QMP use to query and set the behaviour In the following commits we'll clean those up to not directly look at the global variable. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- accel/tcg/tcg-all.c | 21 +++++++++++++++++++++ bsd-user/main.c | 8 ++++++-- linux-user/main.c | 8 ++++++-- softmmu/vl.c | 17 +++++++++++++++-- qemu-options.hx | 7 +++++++ 5 files changed, 55 insertions(+), 6 deletions(-) diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c index 5dab1ae9dd3..fcf361c8db6 100644 --- a/accel/tcg/tcg-all.c +++ b/accel/tcg/tcg-all.c @@ -42,6 +42,7 @@ struct TCGState { AccelState parent_obj; bool mttcg_enabled; + bool one_insn_per_tb; int splitwx_enabled; unsigned long tb_size; }; @@ -208,6 +209,20 @@ static void tcg_set_splitwx(Object *obj, bool value, Error **errp) s->splitwx_enabled = value; } +static bool tcg_get_one_insn_per_tb(Object *obj, Error **errp) +{ + TCGState *s = TCG_STATE(obj); + return s->one_insn_per_tb; +} + +static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp) +{ + TCGState *s = TCG_STATE(obj); + s->one_insn_per_tb = value; + /* For the moment, set the global also: this changes the behaviour */ + singlestep = value; +} + static int tcg_gdbstub_supported_sstep_flags(void) { /* @@ -245,6 +260,12 @@ static void tcg_accel_class_init(ObjectClass *oc, void *data) tcg_get_splitwx, tcg_set_splitwx); object_class_property_set_description(oc, "split-wx", "Map jit pages into separate RW and RX regions"); + + object_class_property_add_bool(oc, "one-insn-per-tb", + tcg_get_one_insn_per_tb, + tcg_set_one_insn_per_tb); + object_class_property_set_description(oc, "one-insn-per-tb", + "Only put one guest insn in each translation block"); } static const TypeInfo tcg_accel_type = { diff --git a/bsd-user/main.c b/bsd-user/main.c index babc3b009b6..09b84da190c 100644 --- a/bsd-user/main.c +++ b/bsd-user/main.c @@ -50,6 +50,7 @@ #include "target_arch_cpu.h" int singlestep; +static bool opt_one_insn_per_tb; uintptr_t guest_base; bool have_guest_base; /* @@ -386,7 +387,7 @@ int main(int argc, char **argv) } else if (!strcmp(r, "seed")) { seed_optarg = optarg; } else if (!strcmp(r, "singlestep")) { - singlestep = 1; + opt_one_insn_per_tb = true; } else if (!strcmp(r, "strace")) { do_strace = 1; } else if (!strcmp(r, "trace")) { @@ -444,9 +445,12 @@ int main(int argc, char **argv) /* init tcg before creating CPUs and to get qemu_host_page_size */ { - AccelClass *ac = ACCEL_GET_CLASS(current_accel()); + AccelState *accel = current_accel(); + AccelClass *ac = ACCEL_GET_CLASS(accel); accel_init_interfaces(ac); + object_property_set_bool(OBJECT(accel), "one-insn-per-tb", + opt_one_insn_per_tb, &error_abort); ac->init_machine(NULL); } cpu = cpu_create(cpu_type); diff --git a/linux-user/main.c b/linux-user/main.c index fe03293516a..489694ad654 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -69,6 +69,7 @@ char *exec_path; char real_exec_path[PATH_MAX]; int singlestep; +static bool opt_one_insn_per_tb; static const char *argv0; static const char *gdbstub; static envlist_t *envlist; @@ -411,7 +412,7 @@ static void handle_arg_reserved_va(const char *arg) static void handle_arg_singlestep(const char *arg) { - singlestep = 1; + opt_one_insn_per_tb = true; } static void handle_arg_strace(const char *arg) @@ -777,9 +778,12 @@ int main(int argc, char **argv, char **envp) /* init tcg before creating CPUs and to get qemu_host_page_size */ { - AccelClass *ac = ACCEL_GET_CLASS(current_accel()); + AccelState *accel = current_accel(); + AccelClass *ac = ACCEL_GET_CLASS(accel); accel_init_interfaces(ac); + object_property_set_bool(OBJECT(accel), "one-insn-per-tb", + opt_one_insn_per_tb, &error_abort); ac->init_machine(NULL); } cpu = cpu_create(cpu_type); diff --git a/softmmu/vl.c b/softmmu/vl.c index ea20b23e4c8..492b5fe65e6 100644 --- a/softmmu/vl.c +++ b/softmmu/vl.c @@ -182,6 +182,7 @@ static const char *log_file; static bool list_data_dirs; static const char *qtest_chrdev; static const char *qtest_log; +static bool opt_one_insn_per_tb; static int has_defaults = 1; static int default_serial = 1; @@ -2220,7 +2221,19 @@ static int do_configure_accelerator(void *opaque, QemuOpts *opts, Error **errp) qemu_opt_foreach(opts, accelerator_set_property, accel, &error_fatal); - + /* + * If legacy -singlestep option is set, honour it for TCG and + * silently ignore for any other accelerator (which is how this + * option has always behaved). + */ + if (opt_one_insn_per_tb) { + /* + * This will always succeed for TCG, and we want to ignore + * the error from trying to set a nonexistent property + * on any other accelerator. + */ + object_property_set_bool(OBJECT(accel), "one-insn-per-tb", true, NULL); + } ret = accel_init_machine(accel, current_machine); if (ret < 0) { if (!qtest_with_kvm || ret != -ENOENT) { @@ -2955,7 +2968,7 @@ void qemu_init(int argc, char **argv) qdict_put_str(machine_opts_dict, "firmware", optarg); break; case QEMU_OPTION_singlestep: - singlestep = 1; + opt_one_insn_per_tb = true; break; case QEMU_OPTION_S: autostart = 0; diff --git a/qemu-options.hx b/qemu-options.hx index 59bdf67a2c5..1dffd36884e 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -182,6 +182,7 @@ DEF("accel", HAS_ARG, QEMU_OPTION_accel, " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" + " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" " split-wx=on|off (enable TCG split w^x mapping)\n" " tb-size=n (TCG translation block cache size)\n" " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" @@ -210,6 +211,12 @@ SRST ``kvm-shadow-mem=size`` Defines the size of the KVM shadow MMU. + ``one-insn-per-tb=on|off`` + Makes the TCG accelerator put only one guest instruction into + each translation block. This slows down emulation a lot, but + can be useful in some situations, such as when trying to analyse + the logs produced by the ``-d`` option. + ``split-wx=on|off`` Controls the use of split w^x mapping for the TCG code generation buffer. Some operating systems require this to be enabled, and in -- 2.34.1
The HMP 'singlestep' command, the QMP 'query-status' command and the HMP 'info status' command (which is just wrapping the QMP command implementation) look at the 'singlestep' global variable. Make them access the new TCG accelerator 'one-insn-per-tb' property instead. This leaves the HMP and QMP command/field names and output strings unchanged; we will clean that up later. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- softmmu/runstate-hmp-cmds.c | 18 ++++++++++++++++-- softmmu/runstate.c | 10 +++++++++- 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/softmmu/runstate-hmp-cmds.c b/softmmu/runstate-hmp-cmds.c index d55a7d4db89..127521a483a 100644 --- a/softmmu/runstate-hmp-cmds.c +++ b/softmmu/runstate-hmp-cmds.c @@ -20,6 +20,7 @@ #include "qapi/error.h" #include "qapi/qapi-commands-run-state.h" #include "qapi/qmp/qdict.h" +#include "qemu/accel.h" void hmp_info_status(Monitor *mon, const QDict *qdict) { @@ -43,13 +44,26 @@ void hmp_info_status(Monitor *mon, const QDict *qdict) void hmp_singlestep(Monitor *mon, const QDict *qdict) { const char *option = qdict_get_try_str(qdict, "option"); + AccelState *accel = current_accel(); + bool newval; + + if (!object_property_find(OBJECT(accel), "one-insn-per-tb")) { + monitor_printf(mon, + "This accelerator does not support setting one-insn-per-tb\n"); + return; + } + if (!option || !strcmp(option, "on")) { - singlestep = 1; + newval = true; } else if (!strcmp(option, "off")) { - singlestep = 0; + newval = false; } else { monitor_printf(mon, "unexpected option %s\n", option); + return; } + /* If the property exists then setting it can never fail */ + object_property_set_bool(OBJECT(accel), "one-insn-per-tb", + newval, &error_abort); } void hmp_watchdog_action(Monitor *mon, const QDict *qdict) diff --git a/softmmu/runstate.c b/softmmu/runstate.c index d1e04586dbc..2f2396c819e 100644 --- a/softmmu/runstate.c +++ b/softmmu/runstate.c @@ -40,6 +40,7 @@ #include "qapi/error.h" #include "qapi/qapi-commands-run-state.h" #include "qapi/qapi-events-run-state.h" +#include "qemu/accel.h" #include "qemu/error-report.h" #include "qemu/job.h" #include "qemu/log.h" @@ -234,9 +235,16 @@ bool runstate_needs_reset(void) StatusInfo *qmp_query_status(Error **errp) { StatusInfo *info = g_malloc0(sizeof(*info)); + AccelState *accel = current_accel(); + /* + * We ignore errors, which will happen if the accelerator + * is not TCG. "singlestep" is meaningless for other accelerators, + * so we will set the StatusInfo field to false for those. + */ + info->singlestep = object_property_get_bool(OBJECT(accel), + "one-insn-per-tb", NULL); info->running = runstate_is_running(); - info->singlestep = singlestep; info->status = current_run_state; return info; -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
The HMP 'singlestep' command, the QMP 'query-status' command and the HMP 'info status' command (which is just wrapping the QMP command implementation) look at the 'singlestep' global variable. Make them access the new TCG accelerator 'one-insn-per-tb' property instead.
This leaves the HMP and QMP command/field names and output strings unchanged; we will clean that up later.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- softmmu/runstate-hmp-cmds.c | 18 ++++++++++++++++-- softmmu/runstate.c | 10 +++++++++- 2 files changed, 25 insertions(+), 3 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The only place left that looks at the old 'singlestep' global variable is the TCG curr_cflags() function. Replace the old global with a new 'one_insn_per_tb' which is defined in tcg-all.c and declared in accel/tcg/internal.h. This keeps it restricted to the TCG code, unlike 'singlestep' which was available to every file in the system and defined in multiple different places for softmmu vs linux-user vs bsd-user. While we're making this change, use qatomic_read() and qatomic_set() on the accesses to the new global, because TCG will read it without holding a lock. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- In discussion on v2, we talked about combining this with the 'nochain' flag so as to have a single 'tcg_cflags_global' that held the flags for the current (one_insn_per_tb, nochain) state. I have not attempted that here, because it's a little tricky: * util/log.c is built into some binaries that don't have an accelerator at all (the tools), so it can't simply call current_accel() to get the TCG accelerator * the initial value of the logging flags is set before the TCG accelerator is even created So I leave that to somebody else to have a go at if they like. --- accel/tcg/internal.h | 2 ++ include/exec/cpu-common.h | 2 -- accel/tcg/cpu-exec.c | 2 +- accel/tcg/tcg-all.c | 6 ++++-- bsd-user/main.c | 1 - linux-user/main.c | 1 - softmmu/globals.c | 1 - 7 files changed, 7 insertions(+), 8 deletions(-) diff --git a/accel/tcg/internal.h b/accel/tcg/internal.h index 96f198b28b4..7bb0fdbe149 100644 --- a/accel/tcg/internal.h +++ b/accel/tcg/internal.h @@ -67,4 +67,6 @@ static inline target_ulong log_pc(CPUState *cpu, const TranslationBlock *tb) extern int64_t max_delay; extern int64_t max_advance; +extern bool one_insn_per_tb; + #endif /* ACCEL_TCG_INTERNAL_H */ diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h index 6feaa40ca7b..0be74f1e706 100644 --- a/include/exec/cpu-common.h +++ b/include/exec/cpu-common.h @@ -163,8 +163,6 @@ int cpu_memory_rw_debug(CPUState *cpu, vaddr addr, void *ptr, size_t len, bool is_write); /* vl.c */ -extern int singlestep; - void list_cpus(const char *optarg); #endif /* CPU_COMMON_H */ diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 8370c92c05e..bc0e1c3299a 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -159,7 +159,7 @@ uint32_t curr_cflags(CPUState *cpu) */ if (unlikely(cpu->singlestep_enabled)) { cflags |= CF_NO_GOTO_TB | CF_NO_GOTO_PTR | CF_SINGLE_STEP | 1; - } else if (singlestep) { + } else if (qatomic_read(&one_insn_per_tb)) { 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/tcg-all.c b/accel/tcg/tcg-all.c index fcf361c8db6..a831f8d7c37 100644 --- a/accel/tcg/tcg-all.c +++ b/accel/tcg/tcg-all.c @@ -31,6 +31,7 @@ #include "qapi/error.h" #include "qemu/error-report.h" #include "qemu/accel.h" +#include "qemu/atomic.h" #include "qapi/qapi-builtin-visit.h" #include "qemu/units.h" #if !defined(CONFIG_USER_ONLY) @@ -110,6 +111,7 @@ static void tcg_accel_instance_init(Object *obj) } bool mttcg_enabled; +bool one_insn_per_tb; static int tcg_init_machine(MachineState *ms) { @@ -219,8 +221,8 @@ static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp) { TCGState *s = TCG_STATE(obj); s->one_insn_per_tb = value; - /* For the moment, set the global also: this changes the behaviour */ - singlestep = value; + /* Set the global also: this changes the behaviour */ + qatomic_set(&one_insn_per_tb, value); } static int tcg_gdbstub_supported_sstep_flags(void) diff --git a/bsd-user/main.c b/bsd-user/main.c index 09b84da190c..a9e5a127d38 100644 --- a/bsd-user/main.c +++ b/bsd-user/main.c @@ -49,7 +49,6 @@ #include "host-os.h" #include "target_arch_cpu.h" -int singlestep; static bool opt_one_insn_per_tb; uintptr_t guest_base; bool have_guest_base; diff --git a/linux-user/main.c b/linux-user/main.c index 489694ad654..c7020b413bc 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -68,7 +68,6 @@ char *exec_path; char real_exec_path[PATH_MAX]; -int singlestep; static bool opt_one_insn_per_tb; static const char *argv0; static const char *gdbstub; diff --git a/softmmu/globals.c b/softmmu/globals.c index 39678aa8c58..e83b5428d12 100644 --- a/softmmu/globals.c +++ b/softmmu/globals.c @@ -43,7 +43,6 @@ int vga_interface_type = VGA_NONE; bool vga_interface_created; Chardev *parallel_hds[MAX_PARALLEL_PORTS]; int win2k_install_hack; -int singlestep; int fd_bootchk = 1; int graphic_rotate; QEMUOptionRom option_rom[MAX_OPTION_ROMS]; -- 2.34.1
On 4/17/23 18:40, Peter Maydell wrote:
The only place left that looks at the old 'singlestep' global variable is the TCG curr_cflags() function. Replace the old global with a new 'one_insn_per_tb' which is defined in tcg-all.c and declared in accel/tcg/internal.h. This keeps it restricted to the TCG code, unlike 'singlestep' which was available to every file in the system and defined in multiple different places for softmmu vs linux-user vs bsd-user.
While we're making this change, use qatomic_read() and qatomic_set() on the accesses to the new global, because TCG will read it without holding a lock.
Signed-off-by: Peter Maydell<peter.maydell@linaro.org> --- In discussion on v2, we talked about combining this with the 'nochain' flag so as to have a single 'tcg_cflags_global' that held the flags for the current (one_insn_per_tb, nochain) state. I have not attempted that here, because it's a little tricky: * util/log.c is built into some binaries that don't have an accelerator at all (the tools), so it can't simply call current_accel() to get the TCG accelerator
Ah ha, yes, tricky.
* the initial value of the logging flags is set before the TCG accelerator is even created So I leave that to somebody else to have a go at if they like. --- accel/tcg/internal.h | 2 ++ include/exec/cpu-common.h | 2 -- accel/tcg/cpu-exec.c | 2 +- accel/tcg/tcg-all.c | 6 ++++-- bsd-user/main.c | 1 - linux-user/main.c | 1 - softmmu/globals.c | 1 - 7 files changed, 7 insertions(+), 8 deletions(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 4/17/23 18:40, Peter Maydell wrote:
@@ -219,8 +221,8 @@ static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp) { TCGState *s = TCG_STATE(obj); s->one_insn_per_tb = value; - /* For the moment, set the global also: this changes the behaviour */ - singlestep = value; + /* Set the global also: this changes the behaviour */ + qatomic_set(&one_insn_per_tb, value); }
Oh, one question: is it worth having the TCGState member at all? Seems like these accessors could work just fine with only the global. r~
On Tue, 18 Apr 2023 at 09:05, Richard Henderson <richard.henderson@linaro.org> wrote:
On 4/17/23 18:40, Peter Maydell wrote:
@@ -219,8 +221,8 @@ static void tcg_set_one_insn_per_tb(Object *obj, bool value, Error **errp) { TCGState *s = TCG_STATE(obj); s->one_insn_per_tb = value; - /* For the moment, set the global also: this changes the behaviour */ - singlestep = value; + /* Set the global also: this changes the behaviour */ + qatomic_set(&one_insn_per_tb, value); }
Oh, one question: is it worth having the TCGState member at all? Seems like these accessors could work just fine with only the global.
True at the moment, but if we do ever want to do that refactoring to use a tcg_global_cflags, then we will need the TCGState field, because you can't go from a tcg_global_cflags value back to "what are the one_insn_per_tb and nochain settings currently?". thanks -- PMM
On 17/4/23 18:40, Peter Maydell wrote:
The only place left that looks at the old 'singlestep' global variable is the TCG curr_cflags() function. Replace the old global with a new 'one_insn_per_tb' which is defined in tcg-all.c and declared in accel/tcg/internal.h. This keeps it restricted to the TCG code, unlike 'singlestep' which was available to every file in the system and defined in multiple different places for softmmu vs linux-user vs bsd-user.
While we're making this change, use qatomic_read() and qatomic_set() on the accesses to the new global, because TCG will read it without holding a lock.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- In discussion on v2, we talked about combining this with the 'nochain' flag so as to have a single 'tcg_cflags_global' that held the flags for the current (one_insn_per_tb, nochain) state. I have not attempted that here, because it's a little tricky: * util/log.c is built into some binaries that don't have an accelerator at all (the tools), so it can't simply call current_accel() to get the TCG accelerator * the initial value of the logging flags is set before the TCG accelerator is even created So I leave that to somebody else to have a go at if they like. --- accel/tcg/internal.h | 2 ++ include/exec/cpu-common.h | 2 -- accel/tcg/cpu-exec.c | 2 +- accel/tcg/tcg-all.c | 6 ++++-- bsd-user/main.c | 1 - linux-user/main.c | 1 - softmmu/globals.c | 1 - 7 files changed, 7 insertions(+), 8 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations. Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> --- docs/user/main.rst | 7 ++++++- linux-user/main.c | 9 ++++++--- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/docs/user/main.rst b/docs/user/main.rst index 6f2ffa080f7..f9ac701f4b1 100644 --- a/docs/user/main.rst +++ b/docs/user/main.rst @@ -93,8 +93,13 @@ Debug options: ``-g port`` Wait gdb connection to port +``-one-insn-per-tb`` + Run the emulation with one guest instruction per translation block. + This slows down emulation a lot, but can be useful in some situations, + such as when trying to analyse the logs produced by the ``-d`` option. + ``-singlestep`` - Run the emulation in single step mode. + This is a deprecated synonym for the ``-one-insn-per-tb`` option. Environment variables: diff --git a/linux-user/main.c b/linux-user/main.c index c7020b413bc..5defe5a6db8 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -409,7 +409,7 @@ static void handle_arg_reserved_va(const char *arg) reserved_va = val ? val - 1 : 0; } -static void handle_arg_singlestep(const char *arg) +static void handle_arg_one_insn_per_tb(const char *arg) { opt_one_insn_per_tb = true; } @@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = { "logfile", "write logs to 'logfile' (default stderr)"}, {"p", "QEMU_PAGESIZE", true, handle_arg_pagesize, "pagesize", "set the host page size to 'pagesize'"}, - {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_singlestep, - "", "run in singlestep mode"}, + {"one-insn-per-tb", + "QEMU_ONE_INSN_PER_TB", false, handle_arg_one_insn_per_tb, + "", "run with one guest instruction per emulated TB"}, + {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_one_insn_per_tb, + "", "deprecated synonym for -one-insn-per-tb"}, {"strace", "QEMU_STRACE", false, handle_arg_strace, "", "log system calls"}, {"seed", "QEMU_RAND_SEED", true, handle_arg_seed, -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations.
Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> --- docs/user/main.rst | 7 ++++++- linux-user/main.c | 9 ++++++--- 2 files changed, 12 insertions(+), 4 deletions(-)
@@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = { "logfile", "write logs to 'logfile' (default stderr)"}, {"p", "QEMU_PAGESIZE", true, handle_arg_pagesize, "pagesize", "set the host page size to 'pagesize'"}, - {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_singlestep, - "", "run in singlestep mode"}, + {"one-insn-per-tb", + "QEMU_ONE_INSN_PER_TB", false, handle_arg_one_insn_per_tb, + "", "run with one guest instruction per emulated TB"}, + {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_one_insn_per_tb, + "", "deprecated synonym for -one-insn-per-tb"},
Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here: "deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB" Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
{"strace", "QEMU_STRACE", false, handle_arg_strace, "", "log system calls"}, {"seed", "QEMU_RAND_SEED", true, handle_arg_seed,
On Thu, 20 Apr 2023 at 10:13, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
On 17/4/23 18:40, Peter Maydell wrote:
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations.
Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> --- docs/user/main.rst | 7 ++++++- linux-user/main.c | 9 ++++++--- 2 files changed, 12 insertions(+), 4 deletions(-)
@@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = { "logfile", "write logs to 'logfile' (default stderr)"}, {"p", "QEMU_PAGESIZE", true, handle_arg_pagesize, "pagesize", "set the host page size to 'pagesize'"}, - {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_singlestep, - "", "run in singlestep mode"}, + {"one-insn-per-tb", + "QEMU_ONE_INSN_PER_TB", false, handle_arg_one_insn_per_tb, + "", "run with one guest instruction per emulated TB"}, + {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_one_insn_per_tb, + "", "deprecated synonym for -one-insn-per-tb"},
Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here:
"deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB"
There's not a lot of space in the -help output, and I think in context it's clear enough without. thanks -- PMM
On 20/4/23 11:19, Peter Maydell wrote:
On Thu, 20 Apr 2023 at 10:13, Philippe Mathieu-Daudé <philmd@linaro.org> wrote:
On 17/4/23 18:40, Peter Maydell wrote:
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations.
Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> --- docs/user/main.rst | 7 ++++++- linux-user/main.c | 9 ++++++--- 2 files changed, 12 insertions(+), 4 deletions(-)
@@ -500,8 +500,11 @@ static const struct qemu_argument arg_table[] = { "logfile", "write logs to 'logfile' (default stderr)"}, {"p", "QEMU_PAGESIZE", true, handle_arg_pagesize, "pagesize", "set the host page size to 'pagesize'"}, - {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_singlestep, - "", "run in singlestep mode"}, + {"one-insn-per-tb", + "QEMU_ONE_INSN_PER_TB", false, handle_arg_one_insn_per_tb, + "", "run with one guest instruction per emulated TB"}, + {"singlestep", "QEMU_SINGLESTEP", false, handle_arg_one_insn_per_tb, + "", "deprecated synonym for -one-insn-per-tb"},
Maybe worth mentioning QEMU_ONE_INSN_PER_TB too here:
"deprecated synonyms for -one-insn-per-tb and QEMU_ONE_INSN_PER_TB"
There's not a lot of space in the -help output, and I think in context it's clear enough without.
Fine.
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations. Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/user/main.rst | 7 ++++++- bsd-user/main.c | 5 +++-- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/docs/user/main.rst b/docs/user/main.rst index f9ac701f4b1..f4786353965 100644 --- a/docs/user/main.rst +++ b/docs/user/main.rst @@ -247,5 +247,10 @@ Debug options: ``-p pagesize`` Act as if the host page size was 'pagesize' bytes +``-one-insn-per-tb`` + Run the emulation with one guest instruction per translation block. + This slows down emulation a lot, but can be useful in some situations, + such as when trying to analyse the logs produced by the ``-d`` option. + ``-singlestep`` - Run the emulation in single step mode. + This is a deprecated synonym for the ``-one-insn-per-tb`` option. diff --git a/bsd-user/main.c b/bsd-user/main.c index a9e5a127d38..cd8b2a670f7 100644 --- a/bsd-user/main.c +++ b/bsd-user/main.c @@ -162,7 +162,8 @@ static void usage(void) "-d item1[,...] enable logging of specified items\n" " (use '-d help' for a list of log items)\n" "-D logfile write logs to 'logfile' (default stderr)\n" - "-singlestep always run in singlestep mode\n" + "-one-insn-per-tb run with one guest instruction per emulated TB\n" + "-singlestep deprecated synonym for -one-insn-per-tb\n" "-strace log system calls\n" "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" " specify tracing options\n" @@ -385,7 +386,7 @@ int main(int argc, char **argv) (void) envlist_unsetenv(envlist, "LD_PRELOAD"); } else if (!strcmp(r, "seed")) { seed_optarg = optarg; - } else if (!strcmp(r, "singlestep")) { + } else if (!strcmp(r, "singlestep") || !strcmp(r, "one-insn-per-tb")) { opt_one_insn_per_tb = true; } else if (!strcmp(r, "strace")) { do_strace = 1; -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
The '-singlestep' option is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations.
Create a new command line argument -one-insn-per-tb, so we can document that -singlestep is just a deprecated synonym for it, and eventually perhaps drop it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/user/main.rst | 7 ++++++- bsd-user/main.c | 5 +++-- 2 files changed, 9 insertions(+), 3 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Document that the -singlestep command line option is now deprecated, as it is replaced by either the TCG accelerator property 'one-insn-per-tb' for system emulation or the new '-one-insn-per-tb' option for usermode emulation, and remove the only use of the deprecated syntax from a README. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/about/deprecated.rst | 16 ++++++++++++++++ qemu-options.hx | 5 +++-- tcg/tci/README | 2 +- 3 files changed, 20 insertions(+), 3 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 1ca9dc33d61..3c62671dac1 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -111,6 +111,22 @@ Use ``-machine acpi=off`` instead. The HAXM project has been retired (see https://github.com/intel/haxm#status). Use "whpx" (on Windows) or "hvf" (on macOS) instead. +``-singlestep`` (since 8.1) +''''''''''''''''''''''''''' + +The ``-singlestep`` option has been turned into an accelerator property, +and given a name that better reflects what it actually does. +Use ``-accel tcg,one-insn-per-tb=on`` instead. + +User-mode emulator command line arguments +----------------------------------------- + +``-singlestep`` (since 8.1) +''''''''''''''''''''''''''' + +The ``-singlestep`` option has been given a name that better reflects +what it actually does. For both linux-user and bsd-user, use the +new ``-one-insn-per-tb`` option instead. QEMU Machine Protocol (QMP) commands ------------------------------------ diff --git a/qemu-options.hx b/qemu-options.hx index 1dffd36884e..6a59e997497 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -4159,10 +4159,11 @@ SRST ERST DEF("singlestep", 0, QEMU_OPTION_singlestep, \ - "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) + "-singlestep deprecated synonym for -accel tcg,one-insn-per-tb=on\n", QEMU_ARCH_ALL) SRST ``-singlestep`` - Run the emulation in single step mode. + This is a deprecated synonym for the TCG accelerator property + ``one-insn-per-tb``. ERST DEF("preconfig", 0, QEMU_OPTION_preconfig, \ diff --git a/tcg/tci/README b/tcg/tci/README index f72a40a395a..4a8b5b54018 100644 --- a/tcg/tci/README +++ b/tcg/tci/README @@ -49,7 +49,7 @@ The only difference from running QEMU with TCI to running without TCI should be speed. Especially during development of TCI, it was very useful to compare runs with and without TCI. Create /tmp/qemu.log by - qemu-system-i386 -d in_asm,op_opt,cpu -D /tmp/qemu.log -singlestep + qemu-system-i386 -d in_asm,op_opt,cpu -D /tmp/qemu.log -accel tcg,one-insn-per-tb=on once with interpreter and once without interpreter and compare the resulting qemu.log files. This is also useful to see the effects of additional -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
Document that the -singlestep command line option is now deprecated, as it is replaced by either the TCG accelerator property 'one-insn-per-tb' for system emulation or the new '-one-insn-per-tb' option for usermode emulation, and remove the only use of the deprecated syntax from a README.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/about/deprecated.rst | 16 ++++++++++++++++ qemu-options.hx | 5 +++-- tcg/tci/README | 2 +- 3 files changed, 20 insertions(+), 3 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Currently we report whether the TCG accelerator is in 'one-insn-per-tb' mode in the 'info status' output. This is a pretty minor piece of TCG specific information, and we want to deprecate the 'singlestep' field of the associated QMP command. Move the 'one-insn-per-tb' reporting to 'info jit'. We don't need a deprecate-and-drop period for this because the HMP interface has no stability guarantees. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- The new 'accelerator settings' subsection of the output currently only has one item, but it would be a place to put other stuff, eg if we wanted to mention whether split-wx is enabled. --- accel/tcg/monitor.c | 14 ++++++++++++++ softmmu/runstate-hmp-cmds.c | 5 ++--- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/accel/tcg/monitor.c b/accel/tcg/monitor.c index 1450e160e95..92fce580f11 100644 --- a/accel/tcg/monitor.c +++ b/accel/tcg/monitor.c @@ -7,6 +7,7 @@ */ #include "qemu/osdep.h" +#include "qemu/accel.h" #include "qapi/error.h" #include "qapi/type-helpers.h" #include "qapi/qapi-commands-machine.h" @@ -36,6 +37,18 @@ static void dump_drift_info(GString *buf) } } +static void dump_accel_info(GString *buf) +{ + AccelState *accel = current_accel(); + bool one_insn_per_tb = object_property_get_bool(OBJECT(accel), + "one-insn-per-tb", + &error_fatal); + + g_string_append_printf(buf, "Accelerator settings:\n"); + g_string_append_printf(buf, "one-insn-per-tb: %s\n\n", + one_insn_per_tb ? "on" : "off"); +} + HumanReadableText *qmp_x_query_jit(Error **errp) { g_autoptr(GString) buf = g_string_new(""); @@ -45,6 +58,7 @@ HumanReadableText *qmp_x_query_jit(Error **errp) return NULL; } + dump_accel_info(buf); dump_exec_info(buf); dump_drift_info(buf); diff --git a/softmmu/runstate-hmp-cmds.c b/softmmu/runstate-hmp-cmds.c index 127521a483a..a477838dc5a 100644 --- a/softmmu/runstate-hmp-cmds.c +++ b/softmmu/runstate-hmp-cmds.c @@ -28,9 +28,8 @@ void hmp_info_status(Monitor *mon, const QDict *qdict) info = qmp_query_status(NULL); - monitor_printf(mon, "VM status: %s%s", - info->running ? "running" : "paused", - info->singlestep ? " (single step mode)" : ""); + monitor_printf(mon, "VM status: %s", + info->running ? "running" : "paused"); if (!info->running && info->status != RUN_STATE_PAUSED) { monitor_printf(mon, " (%s)", RunState_str(info->status)); -- 2.34.1
On 4/17/23 18:40, Peter Maydell wrote:
Currently we report whether the TCG accelerator is in 'one-insn-per-tb' mode in the 'info status' output. This is a pretty minor piece of TCG specific information, and we want to deprecate the 'singlestep' field of the associated QMP command. Move the 'one-insn-per-tb' reporting to 'info jit'.
We don't need a deprecate-and-drop period for this because the HMP interface has no stability guarantees.
Signed-off-by: Peter Maydell<peter.maydell@linaro.org> --- The new 'accelerator settings' subsection of the output currently only has one item, but it would be a place to put other stuff, eg if we wanted to mention whether split-wx is enabled. --- accel/tcg/monitor.c | 14 ++++++++++++++ softmmu/runstate-hmp-cmds.c | 5 ++--- 2 files changed, 16 insertions(+), 3 deletions(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 17/4/23 18:40, Peter Maydell wrote:
Currently we report whether the TCG accelerator is in 'one-insn-per-tb' mode in the 'info status' output. This is a pretty minor piece of TCG specific information, and we want to deprecate the 'singlestep' field of the associated QMP command. Move the 'one-insn-per-tb' reporting to 'info jit'.
We don't need a deprecate-and-drop period for this because the HMP interface has no stability guarantees.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- The new 'accelerator settings' subsection of the output currently only has one item, but it would be a place to put other stuff, eg if we wanted to mention whether split-wx is enabled.
Ideally we should have a AccelClass::qmp_query_info() handler optionally implemented by accelerators, and a single HMP 'info accel' which convert the QMP handler result to human text. This is a start :) Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
--- accel/tcg/monitor.c | 14 ++++++++++++++ softmmu/runstate-hmp-cmds.c | 5 ++--- 2 files changed, 16 insertions(+), 3 deletions(-)
The 'singlestep' HMP command is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations. Create a new HMP command 'one-insn-per-tb', so we can document that 'singlestep' is just a deprecated synonym for it, and eventually perhaps drop it. We aren't obliged to do deprecate-and-drop for HMP commands, but it's easy enough to do so, so we do. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/about/deprecated.rst | 9 +++++++++ include/monitor/hmp.h | 2 +- softmmu/runstate-hmp-cmds.c | 2 +- tests/qtest/test-hmp.c | 1 + hmp-commands.hx | 25 +++++++++++++++++++++---- 5 files changed, 33 insertions(+), 6 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 3c62671dac1..6f5e689aa45 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -199,6 +199,15 @@ accepted incorrect commands will return an error. Users should make sure that all arguments passed to ``device_add`` are consistent with the documented property types. +Human Monitor Protocol (HMP) commands +------------------------------------- + +``singlestep`` (since 8.1) +'''''''''''''''''''''''''' + +The ``singlestep`` command has been replaced by the ``one-insn-per-tb`` +command, which has the same behaviour but a less misleading name. + Host Architectures ------------------ diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h index fdb69b7f9ca..13f9a2dedb8 100644 --- a/include/monitor/hmp.h +++ b/include/monitor/hmp.h @@ -158,7 +158,7 @@ void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict); void hmp_human_readable_text_helper(Monitor *mon, HumanReadableText *(*qmp_handler)(Error **)); void hmp_info_stats(Monitor *mon, const QDict *qdict); -void hmp_singlestep(Monitor *mon, const QDict *qdict); +void hmp_one_insn_per_tb(Monitor *mon, const QDict *qdict); void hmp_watchdog_action(Monitor *mon, const QDict *qdict); void hmp_pcie_aer_inject_error(Monitor *mon, const QDict *qdict); void hmp_info_capture(Monitor *mon, const QDict *qdict); diff --git a/softmmu/runstate-hmp-cmds.c b/softmmu/runstate-hmp-cmds.c index a477838dc5a..2df670f0c06 100644 --- a/softmmu/runstate-hmp-cmds.c +++ b/softmmu/runstate-hmp-cmds.c @@ -40,7 +40,7 @@ void hmp_info_status(Monitor *mon, const QDict *qdict) qapi_free_StatusInfo(info); } -void hmp_singlestep(Monitor *mon, const QDict *qdict) +void hmp_one_insn_per_tb(Monitor *mon, const QDict *qdict) { const char *option = qdict_get_try_str(qdict, "option"); AccelState *accel = current_accel(); diff --git a/tests/qtest/test-hmp.c b/tests/qtest/test-hmp.c index b4a920df898..6704be239be 100644 --- a/tests/qtest/test-hmp.c +++ b/tests/qtest/test-hmp.c @@ -56,6 +56,7 @@ static const char *hmp_cmds[] = { "o /w 0 0x1234", "object_add memory-backend-ram,id=mem1,size=256M", "object_del mem1", + "one-insn-per-tb on", "pmemsave 0 4096 \"/dev/null\"", "p $pc + 8", "qom-list /", diff --git a/hmp-commands.hx b/hmp-commands.hx index bb85ee1d267..9afbb54a515 100644 --- a/hmp-commands.hx +++ b/hmp-commands.hx @@ -378,18 +378,35 @@ SRST only *tag* as parameter. ERST + { + .name = "one-insn-per-tb", + .args_type = "option:s?", + .params = "[on|off]", + .help = "run emulation with one guest instruction per translation block", + .cmd = hmp_one_insn_per_tb, + }, + +SRST +``one-insn-per-tb [off]`` + Run the emulation with one guest instruction per translation block. + This slows down emulation a lot, but can be useful in some situations, + such as when trying to analyse the logs produced by the ``-d`` option. + This only has an effect when using TCG, not with KVM or other accelerators. + + If called with option off, the emulation returns to normal mode. +ERST + { .name = "singlestep", .args_type = "option:s?", .params = "[on|off]", - .help = "run emulation in singlestep mode or switch to normal mode", - .cmd = hmp_singlestep, + .help = "deprecated synonym for one-insn-per-tb", + .cmd = hmp_one_insn_per_tb, }, SRST ``singlestep [off]`` - Run the emulation in single step mode. - If called with option off, the emulation returns to normal mode. + This is a deprecated synonym for the one-insn-per-tb command. ERST { -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
The 'singlestep' HMP command is confusing, because it doesn't actually have anything to do with single-stepping the CPU. What it does do is force TCG emulation to put one guest instruction in each TB, which can be useful in some situations.
Create a new HMP command 'one-insn-per-tb', so we can document that 'singlestep' is just a deprecated synonym for it, and eventually perhaps drop it.
We aren't obliged to do deprecate-and-drop for HMP commands, but it's easy enough to do so, so we do.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- docs/about/deprecated.rst | 9 +++++++++ include/monitor/hmp.h | 2 +- softmmu/runstate-hmp-cmds.c | 2 +- tests/qtest/test-hmp.c | 1 + hmp-commands.hx | 25 +++++++++++++++++++++---- 5 files changed, 33 insertions(+), 6 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The run-state.json file is missing a trailing newline; add it. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- Noticed this because my editor wanted to add the newline when I touched the file for the following patch... --- qapi/run-state.json | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/qapi/run-state.json b/qapi/run-state.json index 419c188dd1a..9d34afa39e0 100644 --- a/qapi/run-state.json +++ b/qapi/run-state.json @@ -663,4 +663,4 @@ # Since: 7.2 ## { 'enum': 'NotifyVmexitOption', - 'data': [ 'run', 'internal-error', 'disable' ] } \ No newline at end of file + 'data': [ 'run', 'internal-error', 'disable' ] } -- 2.34.1
On 17/4/23 18:40, Peter Maydell wrote:
The run-state.json file is missing a trailing newline; add it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> --- Noticed this because my editor wanted to add the newline when I touched the file for the following patch... --- qapi/run-state.json | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
The 'singlestep' member of StatusInfo has never done what the QMP documentation claims it does. What it actually reports is whether TCG is working in "one guest instruction per translation block" mode. We no longer need this field for the HMP 'info status' command, as we've moved that information to 'info jit'. It seems unlikely that anybody is monitoring the state of this obscure TCG setting via QMP, especially since QMP provides no means for changing the setting. So simply deprecate the field, without providing any replacement. Until we do eventually delete the member, correct the misstatements in the QAPI documentation about it. If we do find that there are users for this, then the most likely way we would provide replacement access to the information would be to put the accelerator QOM object at a well-known path such as /machine/accel, which could then be used with the existing qom-set and qom-get commands. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- For v3: because we're only deprecating the existing member, not trying to provide a replacement with a new name, we don't need to update the iotests that use the command. (We will when we eventually drop the deprecated member.) --- docs/about/deprecated.rst | 14 ++++++++++++++ qapi/run-state.json | 14 +++++++++++--- 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 6f5e689aa45..d5eda0f566c 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -199,6 +199,20 @@ accepted incorrect commands will return an error. Users should make sure that all arguments passed to ``device_add`` are consistent with the documented property types. +``StatusInfo`` member ``singlestep`` (since 8.1) +'''''''''''''''''''''''''''''''''''''''''''''''' + +The ``singlestep`` member of the ``StatusInfo`` returned from the +``query-status`` command is deprecated. This member has a confusing +name and it never did what the documentation claimed or what its name +suggests. We do not believe that anybody is actually using the +information provided in this member. + +The information it reports is whether the TCG JIT is in "one +instruction per translated block" mode (which can be set on the +command line or via the HMP, but not via QMP). The information remains +available via the HMP 'info jit' command. + Human Monitor Protocol (HMP) commands ------------------------------------- diff --git a/qapi/run-state.json b/qapi/run-state.json index 9d34afa39e0..daf03a6fe9c 100644 --- a/qapi/run-state.json +++ b/qapi/run-state.json @@ -104,16 +104,24 @@ # # @running: true if all VCPUs are runnable, false if not runnable # -# @singlestep: true if VCPUs are in single-step mode +# @singlestep: true if using TCG with one guest instruction +# per translation block # # @status: the virtual machine @RunState # +# Features: +# @deprecated: Member 'singlestep' is deprecated (with no replacement). +# # Since: 0.14 # -# Notes: @singlestep is enabled through the GDB stub +# Notes: @singlestep is enabled on the command line with +# '-accel tcg,one-insn-per-tb=on', or with the HMP +# 'one-insn-per-tb' command. ## { 'struct': 'StatusInfo', - 'data': {'running': 'bool', 'singlestep': 'bool', 'status': 'RunState'} } + 'data': {'running': 'bool', + 'singlestep': { 'type': 'bool', 'features': [ 'deprecated' ]}, + 'status': 'RunState'} } ## # @query-status: -- 2.34.1
On 4/17/23 18:40, Peter Maydell wrote:
The 'singlestep' member of StatusInfo has never done what the QMP documentation claims it does. What it actually reports is whether TCG is working in "one guest instruction per translation block" mode.
We no longer need this field for the HMP 'info status' command, as we've moved that information to 'info jit'. It seems unlikely that anybody is monitoring the state of this obscure TCG setting via QMP, especially since QMP provides no means for changing the setting. So simply deprecate the field, without providing any replacement.
Until we do eventually delete the member, correct the misstatements in the QAPI documentation about it.
If we do find that there are users for this, then the most likely way we would provide replacement access to the information would be to put the accelerator QOM object at a well-known path such as /machine/accel, which could then be used with the existing qom-set and qom-get commands.
Signed-off-by: Peter Maydell<peter.maydell@linaro.org> --- For v3: because we're only deprecating the existing member, not trying to provide a replacement with a new name, we don't need to update the iotests that use the command. (We will when we eventually drop the deprecated member.) --- docs/about/deprecated.rst | 14 ++++++++++++++ qapi/run-state.json | 14 +++++++++++--- 2 files changed, 25 insertions(+), 3 deletions(-)
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On 17/4/23 18:40, Peter Maydell wrote:
The 'singlestep' member of StatusInfo has never done what the QMP documentation claims it does. What it actually reports is whether TCG is working in "one guest instruction per translation block" mode.
We no longer need this field for the HMP 'info status' command, as we've moved that information to 'info jit'. It seems unlikely that anybody is monitoring the state of this obscure TCG setting via QMP, especially since QMP provides no means for changing the setting. So simply deprecate the field, without providing any replacement.
Until we do eventually delete the member, correct the misstatements in the QAPI documentation about it.
If we do find that there are users for this, then the most likely way we would provide replacement access to the information would be to put the accelerator QOM object at a well-known path such as /machine/accel, which could then be used with the existing qom-set and qom-get commands.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- For v3: because we're only deprecating the existing member, not trying to provide a replacement with a new name, we don't need to update the iotests that use the command. (We will when we eventually drop the deprecated member.) --- docs/about/deprecated.rst | 14 ++++++++++++++ qapi/run-state.json | 14 +++++++++++--- 2 files changed, 25 insertions(+), 3 deletions(-)
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Markus -- could I trouble you for a quick review of this patch? It's the only one in the series that touches QMP. Everything else has been reviewed so otherwise this series is ready to go in. thanks -- PMM On Mon, 17 Apr 2023 at 17:40, Peter Maydell <peter.maydell@linaro.org> wrote:
The 'singlestep' member of StatusInfo has never done what the QMP documentation claims it does. What it actually reports is whether TCG is working in "one guest instruction per translation block" mode.
We no longer need this field for the HMP 'info status' command, as we've moved that information to 'info jit'. It seems unlikely that anybody is monitoring the state of this obscure TCG setting via QMP, especially since QMP provides no means for changing the setting. So simply deprecate the field, without providing any replacement.
Until we do eventually delete the member, correct the misstatements in the QAPI documentation about it.
If we do find that there are users for this, then the most likely way we would provide replacement access to the information would be to put the accelerator QOM object at a well-known path such as /machine/accel, which could then be used with the existing qom-set and qom-get commands.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- For v3: because we're only deprecating the existing member, not trying to provide a replacement with a new name, we don't need to update the iotests that use the command. (We will when we eventually drop the deprecated member.) --- docs/about/deprecated.rst | 14 ++++++++++++++ qapi/run-state.json | 14 +++++++++++--- 2 files changed, 25 insertions(+), 3 deletions(-)
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst index 6f5e689aa45..d5eda0f566c 100644 --- a/docs/about/deprecated.rst +++ b/docs/about/deprecated.rst @@ -199,6 +199,20 @@ accepted incorrect commands will return an error. Users should make sure that all arguments passed to ``device_add`` are consistent with the documented property types.
+``StatusInfo`` member ``singlestep`` (since 8.1) +'''''''''''''''''''''''''''''''''''''''''''''''' + +The ``singlestep`` member of the ``StatusInfo`` returned from the +``query-status`` command is deprecated. This member has a confusing +name and it never did what the documentation claimed or what its name +suggests. We do not believe that anybody is actually using the +information provided in this member. + +The information it reports is whether the TCG JIT is in "one +instruction per translated block" mode (which can be set on the +command line or via the HMP, but not via QMP). The information remains +available via the HMP 'info jit' command. + Human Monitor Protocol (HMP) commands -------------------------------------
diff --git a/qapi/run-state.json b/qapi/run-state.json index 9d34afa39e0..daf03a6fe9c 100644 --- a/qapi/run-state.json +++ b/qapi/run-state.json @@ -104,16 +104,24 @@ # # @running: true if all VCPUs are runnable, false if not runnable # -# @singlestep: true if VCPUs are in single-step mode +# @singlestep: true if using TCG with one guest instruction +# per translation block # # @status: the virtual machine @RunState # +# Features: +# @deprecated: Member 'singlestep' is deprecated (with no replacement). +# # Since: 0.14 # -# Notes: @singlestep is enabled through the GDB stub +# Notes: @singlestep is enabled on the command line with +# '-accel tcg,one-insn-per-tb=on', or with the HMP +# 'one-insn-per-tb' command. ## { 'struct': 'StatusInfo', - 'data': {'running': 'bool', 'singlestep': 'bool', 'status': 'RunState'} } + 'data': {'running': 'bool', + 'singlestep': { 'type': 'bool', 'features': [ 'deprecated' ]}, + 'status': 'RunState'} }
## # @query-status: -- 2.34.1
On Mon, 17 Apr 2023 at 17:40, Peter Maydell <peter.maydell@linaro.org> wrote:
The command line option '-singlestep' and its HMP equivalent the 'singlestep' command are very confusingly named, because they have nothing to do with single-stepping the guest (either via the gdb stub or by emulation of guest CPU architectural debug facilities). What they actually do is put TCG into a mode where it puts only one guest instruction into each translation block. This is useful for some circumstances such as when you want the -d debug logging to be easier to interpret, or if you have a finicky guest binary that wants to see interrupts delivered at something other than the end of a basic block.
I'm going to take this series via target-arm.next since I'm doing a pullreq anyway. thanks -- PMM
Peter Maydell <peter.maydell@linaro.org> writes:
On Mon, 17 Apr 2023 at 17:40, Peter Maydell <peter.maydell@linaro.org> wrote:
The command line option '-singlestep' and its HMP equivalent the 'singlestep' command are very confusingly named, because they have nothing to do with single-stepping the guest (either via the gdb stub or by emulation of guest CPU architectural debug facilities). What they actually do is put TCG into a mode where it puts only one guest instruction into each translation block. This is useful for some circumstances such as when you want the -d debug logging to be easier to interpret, or if you have a finicky guest binary that wants to see interrupts delivered at something other than the end of a basic block.
I'm going to take this series via target-arm.next since I'm doing a pullreq anyway.
Yes, please!
participants (4)
-
Markus Armbruster -
Peter Maydell -
Philippe Mathieu-Daudé -
Richard Henderson