diff options
author | Cornelia Huck <cornelia.huck@de.ibm.com> | 2015-12-02 18:31:57 +0100 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2015-12-02 19:34:11 +0200 |
commit | 11380b36196c483ff5c7f800b0f7af6aa53b5657 (patch) | |
tree | 616f8cd145d8c08199f51ba39d9cae715c6d5b9a /hw/s390x | |
parent | 6d0b908a628a7086fa855c68b217cc1e2a5c4c19 (diff) | |
download | hqemu-11380b36196c483ff5c7f800b0f7af6aa53b5657.zip hqemu-11380b36196c483ff5c7f800b0f7af6aa53b5657.tar.gz |
virtio: handle non-virtio-1-capable backend for ccw
If you run a qemu advertising VERSION_1 with an old kernel where
vhost did not yet support VERSION_1, you'll end up with a device
that is {modern pci|ccw revision 1} but does not advertise VERSION_1.
This is not a sensible configuration and is rejected by the Linux
guest drivers.
To fix this, add a ->post_plugged() callback invoked after features
have been queried that can handle the VERSION_1 bit being withdrawn
and change ccw to fall back to revision 0 if VERSION_1 is gone.
Note that pci is _not_ fixed; we'll need to rethink the approach
for the next release but at least for pci it's not a regression.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/s390x')
-rw-r--r-- | hw/s390x/virtio-ccw.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index fb103b7..63da303 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -1555,6 +1555,17 @@ static void virtio_ccw_device_plugged(DeviceState *d, Error **errp) d->hotplugged, 1); } +static void virtio_ccw_post_plugged(DeviceState *d, Error **errp) +{ + VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d); + VirtIODevice *vdev = virtio_bus_get_device(&dev->bus); + + if (!virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1)) { + /* A backend didn't support modern virtio. */ + dev->max_rev = 0; + } +} + static void virtio_ccw_device_unplugged(DeviceState *d) { VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(d); @@ -1891,6 +1902,7 @@ static void virtio_ccw_bus_class_init(ObjectClass *klass, void *data) k->save_config = virtio_ccw_save_config; k->load_config = virtio_ccw_load_config; k->device_plugged = virtio_ccw_device_plugged; + k->post_plugged = virtio_ccw_post_plugged; k->device_unplugged = virtio_ccw_device_unplugged; } |