This series fixes the remaining case where aio_poll() could hang I/O on the main thread due to a missing wakeup. It consists of a bugfix and an optimization, both of which have survived hundreds of tests on aarch64.
Both the bugfix and the optimization come with a formal model of the interactions between the main thread, the VCPU thread doing aio_poll, and the worker thread doing qemu_bh_schedule. The models can test the code both with and without ctx->notify_me, showing that this bug is independent from the other. The patches apply on top of the ctx->notify_me v3. The code changes are really pretty small; the second patch has a good deal of comments too. Paolo Paolo Bonzini (2): AioContext: fix broken placement of event_notifier_test_and_clear AioContext: optimize clearing the EventNotifier aio-posix.c | 2 + aio-win32.c | 2 + async.c | 16 ++++- docs/aio_notify_accept.promela | 152 +++++++++++++++++++++++++++++++++++++++++ docs/aio_notify_bug.promela | 140 +++++++++++++++++++++++++++++++++++++ include/block/aio.h | 32 ++++++++- 6 files changed, 342 insertions(+), 2 deletions(-) create mode 100644 docs/aio_notify_accept.promela create mode 100644 docs/aio_notify_bug.promela -- 2.4.3
