[PATCH RFC 3/3] vhost, kcov: collect coverage from vhost_worker

From: Andrey Konovalov
Date: Thu Oct 17 2019 - 13:44:35 EST


This patch adds kcov_remote_start/kcov_remote_stop annotations to the
vhost_worker function, which is responsible for processing vhost works.
Since vhost_worker is spawned when a vhost device instance is created,
the common kcov handle is used for kcov_remote_start/stop annotations.

Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 15 +++++++++++++++
drivers/vhost/vhost.h | 3 +++
2 files changed, 18 insertions(+)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 36ca2cf419bf..71a349f6b352 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -357,7 +357,13 @@ static int vhost_worker(void *data)
llist_for_each_entry_safe(work, work_next, node, node) {
clear_bit(VHOST_WORK_QUEUED, &work->flags);
__set_current_state(TASK_RUNNING);
+#ifdef CONFIG_KCOV
+ kcov_remote_start(dev->kcov_handle);
+#endif
work->fn(work);
+#ifdef CONFIG_KCOV
+ kcov_remote_stop();
+#endif
if (need_resched())
schedule();
}
@@ -546,6 +552,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev)

/* No owner, become one */
dev->mm = get_task_mm(current);
+#ifdef CONFIG_KCOV
+ dev->kcov_handle = current->kcov_handle;
+#endif
worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
if (IS_ERR(worker)) {
err = PTR_ERR(worker);
@@ -571,6 +580,9 @@ long vhost_dev_set_owner(struct vhost_dev *dev)
if (dev->mm)
mmput(dev->mm);
dev->mm = NULL;
+#ifdef CONFIG_KCOV
+ dev->kcov_handle = 0;
+#endif
err_mm:
return err;
}
@@ -682,6 +694,9 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
if (dev->worker) {
kthread_stop(dev->worker);
dev->worker = NULL;
+#ifdef CONFIG_KCOV
+ dev->kcov_handle = 0;
+#endif
}
if (dev->mm)
mmput(dev->mm);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index e9ed2722b633..010ca1ebcbd5 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -173,6 +173,9 @@ struct vhost_dev {
int iov_limit;
int weight;
int byte_weight;
+#ifdef CONFIG_KCOV
+ u64 kcov_handle;
+#endif
};

bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len);
--
2.23.0.866.gb869b98d4c-goog