Commit 6cecf093 authored by Greg Kurz's avatar Greg Kurz Committed by Peter Maydell
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virtio-9p-device: add minimal unrealize handler 



Since commit 4652f164 "virtio-9p: add savevm
handlers", if the user hot-unplugs a quiescent 9p device and live
migrates, the source QEMU crashes before migration completetion...
This happens because virtio-9p devices have a realize handler which
calls virtio_init() and register_savevm().  Both calls store pointers
to the device internals, that get dereferenced during migration even
if the device got unplugged.

This patch simply adds an unrealize handler to perform minimal
cleanup and avoid the crash.  Hot unplug of non-quiescent 9p devices
is still not supported in QEMU, and not supported by linux guests
either.

Signed-off-by: default avatarGreg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Message-id: 20151208155457.27775.69441.stgit@bahia.huguette.org
[PMM: rewrapped long lines in commit message]
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent c3626ca7

hw/9pfs/virtio-9p-device.c

+12 −0
Original line number Diff line number Diff line
@@ -145,6 +145,17 @@ out: 
    v9fs_path_free(&path);

}



static void virtio_9p_device_unrealize(DeviceState *dev, Error **errp)

{

    VirtIODevice *vdev = VIRTIO_DEVICE(dev);

    V9fsState *s = VIRTIO_9P(dev);



    virtio_cleanup(vdev);

    unregister_savevm(dev, "virtio-9p", s);

    g_free(s->ctx.fs_root);

    g_free(s->tag);

}



/* virtio-9p device */



static Property virtio_9p_properties[] = {
@@ -161,6 +172,7 @@ static void virtio_9p_class_init(ObjectClass *klass, void *data) 
    dc->props = virtio_9p_properties;

    set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);

    vdc->realize = virtio_9p_device_realize;

    vdc->unrealize = virtio_9p_device_unrealize;

    vdc->get_features = virtio_9p_get_features;

    vdc->get_config = virtio_9p_get_config;

}