perf tools: Automatically use guest kcore_dir if present

When registering a guest machine using machine_pid from the id index,
check perf.data for a matching kcore_dir subdirectory and set the
kallsyms file name accordingly. If set, use it to find the machine's
kernel symbols and object code (from kcore).

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: kvm@vger.kernel.org
Link: https://lore.kernel.org/r/20220711093218.10967-23-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2022-07-11 12:32:05 +03:00 committed by Arnaldo Carvalho de Melo
parent 65691e9ff0
commit a5367ecb53
5 changed files with 27 additions and 2 deletions

View File

@ -518,6 +518,25 @@ char *perf_data__kallsyms_name(struct perf_data *data)
return kallsyms_name;
}
char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid)
{
char *kallsyms_name;
struct stat st;
if (!data->is_dir)
return NULL;
if (asprintf(&kallsyms_name, "%s/kcore_dir__%d/kallsyms", data->path, machine_pid) < 0)
return NULL;
if (stat(kallsyms_name, &st)) {
free(kallsyms_name);
return NULL;
}
return kallsyms_name;
}
bool is_perf_data(const char *path)
{
bool ret = false;

View File

@ -101,5 +101,6 @@ unsigned long perf_data__size(struct perf_data *data);
int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz);
bool has_kcore_dir(const char *path);
char *perf_data__kallsyms_name(struct perf_data *data);
char *perf_data__guest_kallsyms_name(struct perf_data *data, pid_t machine_pid);
bool is_perf_data(const char *path);
#endif /* __PERF_DATA_H */

View File

@ -48,6 +48,7 @@ struct machine {
bool single_address_space;
char *root_dir;
char *mmap_name;
char *kallsyms_filename;
struct threads threads[THREADS__TABLE_SIZE];
struct vdso_info *vdso_info;
struct perf_env *env;

View File

@ -2772,6 +2772,8 @@ static int perf_session__register_guest(struct perf_session *session, pid_t mach
return -ENOMEM;
thread__put(thread);
machine->kallsyms_filename = perf_data__guest_kallsyms_name(session->data, machine_pid);
return 0;
}

View File

@ -2300,11 +2300,13 @@ do_kallsyms:
static int dso__load_guest_kernel_sym(struct dso *dso, struct map *map)
{
int err;
const char *kallsyms_filename = NULL;
const char *kallsyms_filename;
struct machine *machine = map__kmaps(map)->machine;
char path[PATH_MAX];
if (machine__is_default_guest(machine)) {
if (machine->kallsyms_filename) {
kallsyms_filename = machine->kallsyms_filename;
} else if (machine__is_default_guest(machine)) {
/*
* if the user specified a vmlinux filename, use it and only
* it, reporting errors to the user if it cannot be used.