David Gibson <da...@gibson.dropbear.id.au> writes: > VirtIO devices now remember which endianness they're operating in in order > to support targets which may have guests of either endianness, such as > powerpc. This endianness state is transferred in a subsection of the > virtio device's information. > > With virtio-rng this can lead to an abort after a loadvm hitting the > assert() in virtio_is_big_endian(). This can be reproduced by doing a > migrate and load from file on a bi-endian target with a virtio-rng device. > The actual guest state isn't particularly important to triggering this. > > The cause is that virtio_rng_load_device() calls virtio_rng_process() which > accesses the ring and thus needs the endianness. However, > virtio_rng_process() is called via virtio_load() before it loads the > subsections. Essentially the ->load callback in VirtioDeviceClass should > only be used for actually reading the device state from the stream, not for > post-load re-initialization. > > This patch fixes the bug by moving the virtio_rng_process() after the call > to virtio_load(). Better yet would be to convert virtio to use vmsd and > have the virtio_rng_process() as a post_load callback, but that's a bigger > project for another day. > > This is bugfix, and should be considered for the 2.2 branch.
"[PATCH for-2.2]" would have been a good idea then. Next time :)
