The memory allocation between hw/block/virtio-blk.c,
hw/block/dataplane/virtio-blk.c, and hw/virtio/dataplane/vring.c is
messy. Structs are allocated in different files than they are freed in.
This is risky and makes memory leaks easier.
Embed VirtQueueElement in VirtIOBlockReq to reduce the amount of memory
allocation we need to juggle. This also makes vring.c and virtio.c
slightly more similar.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
VirtQueueElement is allocated in vring_pop() so it seems to make sense
that vring_push() should free it. Alas, virtio-blk frees
VirtQueueElement itself in virtio_blk_free_request().
This patch solves a double-free assertion in glib's g_slice_free().
Rename vring_free_element() to vring_unmap_element() since it no longer
frees the VirtQueueElement.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Propagate the error return value from get_indirect(). This bug was
introduced in commit 4d684832 ("vring: create a common function to parse
descriptors").
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
When the dataplane thread stops, its vring.c implementation synchronizes
vring state back to virtio.c so we can continue emulating the virtio
device.
This patch ensures that virtio.c's signalled_used_valid flag is reset so
that we do not suppress guest notifications due to stale signalled_used
values.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Load the virtio.c state into vring.c when we start dataplane mode and
vice versa when stopping dataplane mode. This patch makes it possible
to start and stop dataplane any time while the guest is running.
This will eventually allow us to go back to QEMU main loop for
bdrv_drain_all() and live migration. In the meantime, this patch makes
the dataplane lifecycle more robust but should make no visible
difference. It may be useful in the virtio-net dataplane effort.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
