| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20251028152856.1554948-1-nhudson@akamai.com>
Date: Tue, 28 Oct 2025 15:28:54 +0000
From: Nick Hudson <nhudson@...mai.com>
To: "Michael S. Tsirkin" <mst@...hat.com>, Jason Wang <jasowang@...hat.com>,
Eugenio Pérez <eperezma@...hat.com>
Cc: Nick Hudson <nhudson@...mai.com>, Max Tottenham <mtottenh@...mai.com>,
kvm@...r.kernel.org, virtualization@...ts.linux.dev,
netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] vhost: add a new ioctl VHOST_GET_VRING_WORKER_INFO and use in net.c
The vhost_net (and vhost_sock) drivers create worker tasks to handle
the virtual queues. Provide a new ioctl VHOST_GET_VRING_WORKER_INFO that
can be used to determine the PID of these tasks so that, for example,
they can be pinned to specific CPU(s).
Signed-off-by: Nick Hudson <nhudson@...mai.com>
Reviewed-by: Max Tottenham <mtottenh@...mai.com>
---
drivers/vhost/net.c | 5 +++++
drivers/vhost/vhost.c | 19 +++++++++++++++++++
include/linux/sched/vhost_task.h | 2 ++
include/uapi/linux/vhost.h | 3 +++
include/uapi/linux/vhost_types.h | 13 +++++++++++++
kernel/vhost_task.c | 12 ++++++++++++
6 files changed, 54 insertions(+)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 35ded4330431..e86bd5d7d202 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1804,6 +1804,11 @@ static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
return vhost_net_reset_owner(n);
case VHOST_SET_OWNER:
return vhost_net_set_owner(n);
+ case VHOST_GET_VRING_WORKER_INFO:
+ mutex_lock(&n->dev.mutex);
+ r = vhost_worker_ioctl(&n->dev, ioctl, argp);
+ mutex_unlock(&n->dev.mutex);
+ return r;
default:
mutex_lock(&n->dev.mutex);
r = vhost_dev_ioctl(&n->dev, ioctl, argp);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 8570fdf2e14a..20ad9d190dc3 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1012,6 +1012,7 @@ long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
void __user *argp)
{
struct vhost_vring_worker ring_worker;
+ struct vhost_vring_worker_info ring_worker_info;
struct vhost_worker_state state;
struct vhost_worker *worker;
struct vhost_virtqueue *vq;
@@ -1050,6 +1051,7 @@ long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
/* vring worker ioctls */
case VHOST_ATTACH_VRING_WORKER:
case VHOST_GET_VRING_WORKER:
+ case VHOST_GET_VRING_WORKER_INFO:
break;
default:
return -ENOIOCTLCMD;
@@ -1082,6 +1084,23 @@ long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
if (copy_to_user(argp, &ring_worker, sizeof(ring_worker)))
ret = -EFAULT;
break;
+ case VHOST_GET_VRING_WORKER_INFO:
+ worker = rcu_dereference_check(vq->worker,
+ lockdep_is_held(&dev->mutex));
+ if (!worker) {
+ ret = -EINVAL;
+ break;
+ }
+
+ memset(&ring_worker_info, 0, sizeof(ring_worker_info));
+ ring_worker_info.index = idx;
+ ring_worker_info.worker_id = worker->id;
+ ring_worker_info.worker_pid = task_pid_vnr(vhost_get_task(worker->vtsk));
+
+ if (copy_to_user(argp, &ring_worker_info, sizeof(ring_worker_info)))
+ ret = -EFAULT;
+ break;
+
default:
ret = -ENOIOCTLCMD;
break;
diff --git a/include/linux/sched/vhost_task.h b/include/linux/sched/vhost_task.h
index 25446c5d3508..568f9596f29e 100644
--- a/include/linux/sched/vhost_task.h
+++ b/include/linux/sched/vhost_task.h
@@ -11,4 +11,6 @@ void vhost_task_start(struct vhost_task *vtsk);
void vhost_task_stop(struct vhost_task *vtsk);
void vhost_task_wake(struct vhost_task *vtsk);
+struct task_struct *vhost_get_task(struct vhost_task *vtsk);
+
#endif /* _LINUX_SCHED_VHOST_TASK_H */
diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
index c57674a6aa0d..c32aa8c71952 100644
--- a/include/uapi/linux/vhost.h
+++ b/include/uapi/linux/vhost.h
@@ -101,6 +101,9 @@
/* Return the vring worker's ID */
#define VHOST_GET_VRING_WORKER _IOWR(VHOST_VIRTIO, 0x16, \
struct vhost_vring_worker)
+/* Return the vring worker's ID and PID */
+#define VHOST_GET_VRING_WORKER_INFO _IOWR(VHOST_VIRTIO, 0x17, \
+ struct vhost_vring_worker_info)
/* The following ioctls use eventfd file descriptors to signal and poll
* for events. */
diff --git a/include/uapi/linux/vhost_types.h b/include/uapi/linux/vhost_types.h
index 1c39cc5f5a31..28e00f8ade85 100644
--- a/include/uapi/linux/vhost_types.h
+++ b/include/uapi/linux/vhost_types.h
@@ -63,6 +63,19 @@ struct vhost_vring_worker {
unsigned int worker_id;
};
+/* Per-virtqueue worker mapping entry */
+struct vhost_vring_worker_info {
+ /* vring index */
+ unsigned int index;
+ /*
+ * The id of the vhost_worker returned from VHOST_NEW_WORKER or
+ * allocated as part of vhost_dev_set_owner.
+ */
+ unsigned int worker_id;
+
+ __kernel_pid_t worker_pid; /* PID/TID of worker thread, -1 if none */
+};
+
/* no alignment requirement */
struct vhost_iotlb_msg {
__u64 iova;
diff --git a/kernel/vhost_task.c b/kernel/vhost_task.c
index 27107dcc1cbf..aa87a7f0c98a 100644
--- a/kernel/vhost_task.c
+++ b/kernel/vhost_task.c
@@ -67,6 +67,18 @@ static int vhost_task_fn(void *data)
do_exit(0);
}
+/**
+ * vhost_get_task - get a pointer to the vhost_task's task_struct
+ * @vtsk: vhost_task to return the task for
+ *
+ * return the vhost_task's task.
+ */
+struct task_struct *vhost_get_task(struct vhost_task *vtsk)
+{
+ return vtsk->task;
+}
+EXPORT_SYMBOL_GPL(vhost_get_task);
+
/**
* vhost_task_wake - wakeup the vhost_task
* @vtsk: vhost_task to wake
--
2.34.1
Powered by blists - more mailing lists