Commit 0e566c8f authored by Parav Pandit's avatar Parav Pandit Committed by Michael S. Tsirkin
Browse files

virtio: Protect vqs list access 



VQs may be accessed to mark the device broken while they are
created/destroyed. Hence protect the access to the vqs list.

Fixes: e2dcdfe9 ("virtio: virtio_break_device() to mark all virtqueues broken.")
Signed-off-by: default avatarParav Pandit <parav@nvidia.com>
Link: https://lore.kernel.org/r/20210721142648.1525924-4-parav@nvidia.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 249f2554

drivers/virtio/virtio.c

+1 −0
Original line number Diff line number Diff line
@@ -355,6 +355,7 @@ int register_virtio_device(struct virtio_device *dev) 
	virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);



	INIT_LIST_HEAD(&dev->vqs);

	spin_lock_init(&dev->vqs_list_lock);



	/*

	 * device_add() causes the bus infrastructure to look for a matching

drivers/virtio/virtio_ring.c

+8 −0
Original line number Diff line number Diff line
@@ -1755,7 +1755,9 @@ static struct virtqueue *vring_create_virtqueue_packed( 
			cpu_to_le16(vq->packed.event_flags_shadow);

	}



	spin_lock(&vdev->vqs_list_lock);

	list_add_tail(&vq->vq.list, &vdev->vqs);

	spin_unlock(&vdev->vqs_list_lock);

	return &vq->vq;



err_desc_extra:
@@ -2229,7 +2231,9 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, 
	memset(vq->split.desc_state, 0, vring.num *

			sizeof(struct vring_desc_state_split));



	spin_lock(&vdev->vqs_list_lock);

	list_add_tail(&vq->vq.list, &vdev->vqs);

	spin_unlock(&vdev->vqs_list_lock);

	return &vq->vq;



err_extra:
@@ -2291,7 +2295,9 @@ void vring_del_virtqueue(struct virtqueue *_vq) 
{

	struct vring_virtqueue *vq = to_vvq(_vq);



	spin_lock(&vq->vq.vdev->vqs_list_lock);

	list_del(&_vq->list);

	spin_unlock(&vq->vq.vdev->vqs_list_lock);



	if (vq->we_own_ring) {

		if (vq->packed_ring) {
@@ -2386,12 +2392,14 @@ void virtio_break_device(struct virtio_device *dev) 
{

	struct virtqueue *_vq;



	spin_lock(&dev->vqs_list_lock);

	list_for_each_entry(_vq, &dev->vqs, list) {

		struct vring_virtqueue *vq = to_vvq(_vq);



		/* Pairs with READ_ONCE() in virtqueue_is_broken(). */

		WRITE_ONCE(vq->broken, true);

	}

	spin_unlock(&dev->vqs_list_lock);

}

EXPORT_SYMBOL_GPL(virtio_break_device);

include/linux/virtio.h

+1 −0
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ struct virtio_device { 
	bool config_enabled;

	bool config_change_pending;

	spinlock_t config_lock;

	spinlock_t vqs_list_lock; /* Protects VQs list access */

	struct device dev;

	struct virtio_device_id id;

	const struct virtio_config_ops *config;