From f0d634ea1964ccce317818c44fe299e71007e64d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Carlos=20L=C3=B3pez?= Date: Fri, 17 Mar 2023 01:27:51 +0100 Subject: virtio: refresh vring region cache after updating a virtqueue size MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a virtqueue size is changed by the guest via virtio_queue_set_num(), its region cache is not automatically updated. If the size was increased, this could lead to accessing the cache out of bounds. For example, in vring_get_used_event(): static inline uint16_t vring_get_used_event(VirtQueue *vq) { return vring_avail_ring(vq, vq->vring.num); } static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) { VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); hwaddr pa = offsetof(VRingAvail, ring[i]); if (!caches) { return 0; } return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); } vq->vring.num will be greater than caches->avail.len, which will trigger a failed assertion down the call path of virtio_lduw_phys_cached(). Fix this by calling virtio_init_region_cache() after virtio_queue_set_num() if we are not already calling virtio_queue_set_rings(). In the legacy path this is already done by virtio_queue_update_rings(). Signed-off-by: Carlos López Message-Id: <20230317002749.27379-1-clopez@suse.de> Reviewed-by: Cornelia Huck Acked-by: Halil Pasic Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- include/hw/virtio/virtio.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/hw') diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index f236e94..f6b38f7 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -309,6 +309,7 @@ int virtio_get_num_queues(VirtIODevice *vdev); void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc, hwaddr avail, hwaddr used); void virtio_queue_update_rings(VirtIODevice *vdev, int n); +void virtio_init_region_cache(VirtIODevice *vdev, int n); void virtio_queue_set_align(VirtIODevice *vdev, int n, int align); void virtio_queue_notify(VirtIODevice *vdev, int n); uint16_t virtio_queue_vector(VirtIODevice *vdev, int n); -- cgit v1.1