From: Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx>
In order to match host and guest events, a mapping between guest VCPU
and the host task, running this VCPU is needed. Extended existing
struct guest to hold such mapping and added logic in read_qemu_guests()
function to initialize it. Implemented a new internal API,
get_guest_vcpu_pid(), to retrieve VCPU-task mapping for given VM.
Signed-off-by: Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx>
---
tracecmd/include/trace-local.h | 2 ++
tracecmd/trace-record.c | 57 ++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+)
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index a51f0d0..51abef1 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -243,6 +243,8 @@ void update_first_instance(struct buffer_instance *instance, int topt);
void show_instance_file(struct buffer_instance *instance, const char *name);
+int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
+
/* moved from trace-cmd.h */
void tracecmd_create_top_instance(char *name);
void tracecmd_remove_instances(void);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 4459c90..fd7ca82 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2873,10 +2873,12 @@ static bool is_digits(const char *s)
return true;
}
+#define VCPUS_MAX 256
struct guest {
char *name;
int cid;
int pid;
+ int cpu_pid[VCPUS_MAX];
};
static struct guest *guests;
@@ -2894,6 +2896,46 @@ static char *get_qemu_guest_name(char *arg)
return arg;
}
+static void read_qemu_guests_pids(char *guest_task, struct guest *guest)
+{
+ struct dirent *entry;
+ char path[PATH_MAX];
+ char *buf = NULL;
+ size_t n = 0;
+ int vcpu;
+ DIR *dir;
+ FILE *f;
+
+ snprintf(path, sizeof(path), "/proc/%s/task", guest_task);
+ dir = opendir(path);
+ if (!dir)
+ return;
+
+ while ((entry = readdir(dir))) {
+ if (!(entry->d_type == DT_DIR && is_digits(entry->d_name)))
+ continue;
+
+ snprintf(path, sizeof(path), "/proc/%s/task/%s/comm",
+ guest_task, entry->d_name);
+ f = fopen(path, "r");
+ if (!f)
+ continue;
+ if (getline(&buf, &n, f) < 0)
+ goto next;
+ if (strncmp(buf, "CPU ", 4) != 0)
+ goto next;
+
+ vcpu = atoi(buf+4);
+ if (!(vcpu >= 0 && vcpu < VCPUS_MAX))
+ goto next;
+ guest->cpu_pid[vcpu] = atoi(entry->d_name);
+
+next:
+ fclose(f);
+ }
+ free(buf);
+}
+
static void read_qemu_guests(void)
{
static bool initialized;
@@ -2957,6 +2999,8 @@ static void read_qemu_guests(void)
if (!is_qemu)
goto next;
+ read_qemu_guests_pids(entry->d_name, &guest);
+
guests = realloc(guests, (guests_len + 1) * sizeof(*guests));
if (!guests)
die("Can not allocate guest buffer");
@@ -3002,6 +3046,19 @@ static char *parse_guest_name(char *guest, int *cid, int *port)
return guest;
}
+int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu)
+{
+ int i;
+
+ if (!guests || guest_vcpu >= VCPUS_MAX)
+ return -1;
+
+ for (i = 0; i < guests_len; i++)
+ if (guest_cid == guests[i].cid)
+ return guests[i].cpu_pid[guest_vcpu];
+ return -1;
+}
+
static void set_prio(int prio)
{
struct sched_param sp;
--
2.23.0
|