Currently investigating translation involves enabling debugging flags
and potentially generating large amounts of debug information and
sifting through it. -dfilter helps but often you want to investigate
what's going on in a live system. This patch is an attempt at that.
It adds a "info translate" command which is passed an address. It then
grabs the tb_lock, fiddles with the loglevel flags and then does a
un-cached translation, spewing the output on stderr. There are a
number of open questions:
- there is currently no safe way to re-direct log output
- messing with internal qemu_loglevel flags is *eewww*
- we don't deal with translation flags
We could deal with the inherent racey behaviour by pushing the output
to a async safe function. It also might make sense to be able to
introspect what TB's exist in a given range and then use that
information to re-run the translation live.
Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
---
accel/tcg/translate-all.c | 23 +++++++++++++++++++++++
hmp-commands-info.hx | 16 ++++++++++++++++
include/exec/cpu-all.h | 2 ++
monitor.c | 15 +++++++++++++++
4 files changed, 56 insertions(+)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 2d1ed06065..09fc698bb0 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -1947,6 +1947,29 @@ void dump_opcount_info(FILE *f, fprintf_function
cpu_fprintf)
tcg_dump_op_count(f, cpu_fprintf);
}
+/*
+ * To dump translation info we temporally translate the given address
+ * while tweak the log flags to dump information.
+ *
+ * It might make more sense to push this off to an safe async function
+ * to do this in a less racey manner.
+ */
+
+void dump_translate_info(FILE *f, fprintf_function cpu_fprintf,
+ target_ulong addr, int flags)
+{
+ int old_flags = qemu_loglevel;
+
+ /* grab the lock, currently that means no other translation */
+ tb_lock();
+ qemu_loglevel = flags;
+
+ tb_gen_code(first_cpu, addr, 0, 0, CF_NOCACHE | CF_IGNORE_ICOUNT);
+
+ qemu_loglevel = old_flags;
+ tb_unlock();
+}
+
#else /* CONFIG_USER_ONLY */
void cpu_interrupt(CPUState *cpu, int mask)
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index 1c6772597d..68f64aff7e 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -292,6 +292,22 @@ STEXI
@item info opcount
@findex opcount
Show dynamic compiler opcode counters
+ETEXI
+
+#if defined(CONFIG_TCG)
+ {
+ .name = "translate",
+ .args_type = "addr:l,flags:s",
+ .params = "addr [flags]",
+ .help = "show translation info",
+ .cmd = hmp_info_translate,
+ },
+#endif
+
+STEXI
+@item info translate
+@findex translate
+Show dynamic compiler info.
ETEXI
{
diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index ffe43d5654..456fd03f44 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -340,6 +340,8 @@ CPUArchState *cpu_copy(CPUArchState *env);
void dump_exec_info(FILE *f, fprintf_function cpu_fprintf);
void dump_opcount_info(FILE *f, fprintf_function cpu_fprintf);
+void dump_translate_info(FILE *f, fprintf_function cpu_fprintf,
+ target_ulong addr, int flags);
#endif /* !CONFIG_USER_ONLY */
int cpu_memory_rw_debug(CPUState *cpu, target_ulong addr,
diff --git a/monitor.c b/monitor.c
index cd831eaab4..f0cdd54cfb 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1115,6 +1115,21 @@ static void hmp_info_opcount(Monitor *mon, const QDict
*qdict)
{
dump_opcount_info((FILE *)mon, monitor_fprintf);
}
+
+static void hmp_info_translate(Monitor *mon, const QDict *qdict)
+{
+ target_ulong addr;
+
+ if (!tcg_enabled()) {
+ error_report("translation information is only available with
accel=tcg");
+ return;
+ }
+
+ addr = qdict_get_int(qdict, "addr");
+
+ dump_translate_info((FILE *)mon, monitor_fprintf, addr,
+ CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM |
CPU_LOG_TB_OP);
+}
#endif
static void hmp_info_history(Monitor *mon, const QDict *qdict)
--
2.14.1
