[RFC PATCH 5/5] hmp: Add 'one-insn-per-tb' command equivalent to 'singlestep'

[Peter Maydell <peter.maydell@linaro.org>]

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.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 include/monitor/hmp.h       |  2 +-
 softmmu/runstate-hmp-cmds.c |  2 +-
 tests/qtest/test-hmp.c      |  1 +
 hmp-commands.hx             | 25 +++++++++++++++++++++----
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index 2220f14fc98..e66c8c63799 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -156,7 +156,7 @@ 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 29c9a038863..da218aa4b86 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");
     if (!option || !strcmp(option, "on")) {
diff --git a/tests/qtest/test-hmp.c b/tests/qtest/test-hmp.c
index b4a920df898..cb3530df722 100644
--- a/tests/qtest/test-hmp.c
+++ b/tests/qtest/test-hmp.c
@@ -64,6 +64,7 @@ static const char *hmp_cmds[] = {
     "screendump /dev/null",
     "sendkey x",
     "singlestep on",
+    "one-insn-per-tb on",
     "wavcapture /dev/null",
     "stopcapture 0",
     "sum 0 512",
diff --git a/hmp-commands.hx b/hmp-commands.hx
index fbb5daf09be..88933567845 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