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 | 1 +
tracecmd/trace-record.c | 52 ++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 8413054..62f5e47 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -245,6 +245,7 @@ int tracecmd_local_cpu_count(void);
void tracecmd_set_clock(struct buffer_instance *instance);
void tracecmd_remove_instance(struct buffer_instance *instance);
+int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
/* No longer in event-utils.h */
void __noreturn die(const char *fmt, ...); /* Can be overriden */
void *malloc_or_die(unsigned int size); /* Can be overridden */
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 3950242..b4ea40f 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -2746,10 +2746,12 @@ 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;
@@ -2767,6 +2769,41 @@ 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_t;
+ char path[PATH_MAX];
+ unsigned int vcpu;
+ char *buf = NULL;
+ DIR *dir;
+ FILE *ft;
+ size_t n;
+
+ snprintf(path, sizeof(path), "/proc/%s/task", guest_task);
+ dir = opendir(path);
+ if (!dir)
+ return;
+
+ for (entry_t = readdir(dir); entry_t; entry_t = readdir(dir)) {
+ if (!(entry_t->d_type == DT_DIR && is_digits(entry_t->d_name)))
+ continue;
+ snprintf(path, sizeof(path), "/proc/%s/task/%s/comm",
+ guest_task, entry_t->d_name);
+ ft = fopen(path, "r");
+ if (!ft)
+ continue;
+ getline(&buf, &n, ft);
+ if (buf && strncmp(buf, "CPU ", 4) == 0) {
+ vcpu = atoi(buf+4);
+ if (vcpu < VCPUS_MAX)
+ guest->cpu_pid[vcpu] = atoi(entry_t->d_name);
+ }
+ free(buf);
+ fclose(ft);
+ buf = NULL;
+ }
+}
+
static void read_qemu_guests(void)
{
static bool initialized;
@@ -2828,6 +2865,8 @@ 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");
@@ -2873,6 +2912,19 @@ 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;
--
2.20.1
|