On Mon, Dec 16, 2019 at 02:34:51PM +0000, Paul Durrant wrote: > It is not safe to close an event channel from the QEMU main thread when > that channel's poller is running in IOThread context. > > This patch adds a new xen_device_set_event_channel_context() function > to explicitly assign the channel AioContext, and modifies > xen_device_bind_event_channel() to initially assign the channel's poller > to the QEMU main thread context. The code in xen-block's dataplane is > then modified to assign the channel to IOThread context during > xen_block_dataplane_start() and de-assign it during in > xen_block_dataplane_stop(), such that the channel is always assigned > back to main thread context before it is closed. aio_set_fd_handler() > already deals with all the necessary synchronization when moving an fd > between AioContext-s so no extra code is needed to manage this. > > Reported-by: Julien Grall <jgr...@amazon.com> > Signed-off-by: Paul Durrant <pdurr...@amazon.com>
Reviewed-by: Anthony PERARD <anthony.per...@citrix.com> > Tested against an HVM debian guest with a QCOW2 image as system disk, and > as a hot-plugged/unplgged secondary disk. And I've run an osstest flight with the patch. Thanks, -- Anthony PERARD
