[PATCH 3/4] virtio: Protect vqs list access
From: Parav Pandit via Virtualization <hidden>
Date: 2021-07-17 07:43:23
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
VQs may be accessed to mark the device broken while they are
created/destroyed. Hence protect the access to the vqs list.
Fixes: e2dcdfe95c0b ("virtio: virtio_break_device() to mark all virtqueues broken.")
Signed-off-by: Parav Pandit <redacted>
---
drivers/virtio/virtio.c | 1 +
drivers/virtio/virtio_ring.c | 8 ++++++++
include/linux/virtio.h | 1 +
3 files changed, 10 insertions(+)
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 4b15c00c0a0a..a0d81e35ec4b 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c@@ -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); + rwlock_init(&dev->vqs_list_lock); /* * device_add() causes the bus infrastructure to look for a matching
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index d2e1a7a21171..66a91dec39d9 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c@@ -1755,7 +1755,9 @@ static struct virtqueue *vring_create_virtqueue_packed( cpu_to_le16(vq->packed.event_flags_shadow); } + write_lock(&vdev->vqs_list_lock); list_add_tail(&vq->vq.list, &vdev->vqs); + write_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)); + write_lock(&vdev->vqs_list_lock); list_add_tail(&vq->vq.list, &vdev->vqs); + write_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); + write_lock(&vq->vq.vdev->vqs_list_lock); list_del(&_vq->list); + write_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; + read_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(). */ smp_store_release(&vq->broken, true); } + read_unlock(&dev->vqs_list_lock); } EXPORT_SYMBOL_GPL(virtio_break_device);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index b1894e0323fa..1cf77d480ef3 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h@@ -115,6 +115,7 @@ struct virtio_device { const struct virtio_config_ops *config; const struct vringh_config_ops *vringh_config; struct list_head vqs; + rwlock_t vqs_list_lock; u64 features; void *priv; };
--
2.27.0
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