Vhost did not reset properly the batched descriptors on SET_VRING_BASE event. Because of that, is possible to return an invalid descriptor to the guest. This series ammend this, resetting them every time backend changes, and creates a test to assert correct behavior. To do that, they need to expose a new function in virtio_ring, virtqueue_reset_free_head, only on test code. Another useful thing would be to check if mutex is properly get in vq private_data accessors. Not sure if mutex debug code allow that, similar to C++ unique lock::owns_lock. Not acquiring in the function because caller code holds the mutex in order to perform more actions. v2: * Squashed commits. * Create vq private_data accesors (mst). This is meant to be applied on top of c4f1c41a6094582903c75c0dcfacb453c959d457 in git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git. Eugenio Pérez (5): vhost: Create accessors for virtqueues private_data tools/virtio: Add --batch option tools/virtio: Add --batch=random option tools/virtio: Add --reset=random tools/virtio: Make --reset reset ring idx Michael S. Tsirkin (3): vhost: option to fetch descriptors through an independent struct vhost: use batched version by default vhost: batching fetches drivers/vhost/net.c | 28 ++-- drivers/vhost/test.c | 59 +++++++- drivers/vhost/test.h | 1 + drivers/vhost/vhost.c | 271 +++++++++++++++++++++++------------ drivers/vhost/vhost.h | 45 +++++- drivers/vhost/vsock.c | 14 +- drivers/virtio/virtio_ring.c | 29 ++++ tools/virtio/linux/virtio.h | 2 + tools/virtio/virtio_test.c | 123 ++++++++++++++-- 9 files changed, 445 insertions(+), 127 deletions(-) -- 2.18.1