From d74a8cb440796243b0c9b29b05cc30d6b907677d 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 (cherry picked from commit f0d634ea1964ccce317818c44fe299e71007e64d) Signed-off-by: Michael Tokarev (cherry picked from commit f52121827c0ecd218f55c8ed36e8ce5063015097) Signed-off-by: Michael Tokarev --- hw/s390x/virtio-ccw.c | 1 + hw/virtio/virtio-mmio.c | 1 + hw/virtio/virtio-pci.c | 1 + hw/virtio/virtio.c | 2 +- include/hw/virtio/virtio.h | 1 + 5 files changed, 5 insertions(+), 1 deletion(-) diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index e33e5207ab..f44de1a8c1 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -237,6 +237,7 @@ static int virtio_ccw_set_vqs(SubchDev *sch, VqInfoBlock *info, return -EINVAL; } virtio_queue_set_num(vdev, index, num); + virtio_init_region_cache(vdev, index); } else if (virtio_queue_get_num(vdev, index) > num) { /* Fail if we don't have a big enough queue. */ return -EINVAL; diff --git a/hw/virtio/virtio-mmio.c b/hw/virtio/virtio-mmio.c index d240efef97..3580b98541 100644 --- a/hw/virtio/virtio-mmio.c +++ b/hw/virtio/virtio-mmio.c @@ -354,6 +354,7 @@ static void virtio_mmio_write(void *opaque, hwaddr offset, uint64_t value, if (proxy->legacy) { virtio_queue_update_rings(vdev, vdev->queue_sel); } else { + virtio_init_region_cache(vdev, vdev->queue_sel); proxy->vqs[vdev->queue_sel].num = value; } break; diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c index a1c9dfa7bb..f3a380a5ca 100644 --- a/hw/virtio/virtio-pci.c +++ b/hw/virtio/virtio-pci.c @@ -1346,6 +1346,7 @@ static void virtio_pci_common_write(void *opaque, hwaddr addr, proxy->vqs[vdev->queue_sel].num = val; virtio_queue_set_num(vdev, vdev->queue_sel, proxy->vqs[vdev->queue_sel].num); + virtio_init_region_cache(vdev, vdev->queue_sel); break; case VIRTIO_PCI_COMMON_Q_MSIX: vector = virtio_queue_vector(vdev, vdev->queue_sel); diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index eb6347ab5d..c5b640cb31 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -635,7 +635,7 @@ static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq) } } -static void virtio_init_region_cache(VirtIODevice *vdev, int n) +void virtio_init_region_cache(VirtIODevice *vdev, int n) { VirtQueue *vq = &vdev->vq[n]; VRingMemoryRegionCaches *old = vq->vring.caches; diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h index acfd4df125..1e250a922e 100644 --- a/include/hw/virtio/virtio.h +++ b/include/hw/virtio/virtio.h @@ -289,6 +289,7 @@ 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 v1.2.1