[Qemu-devel] Timer issues with 2.1.1 and migration (was: latest rc: virtio-blk hangs forever after migration)

[Andrey Korolyov]

Hello,

there is a somewhat weird issue with 3.10, backported IOAPIC behavior
(which allowed windows guest to not hang in my case), 2.1.1 and webkit
suite which is well-known for all timer weirdness for Windows guests.
Here is a way to reproduce:

- start the guest,
- open webkit-based browser, cpu consumption will raise a bit but with
hv_ bits will remain under single core in my case,
- live-migrate VM,
- close browser,
- observe 100% cpu consumption by guest.

The loop can be 'destroyed' by doing another live migration, e.g.
without something what drives guest timer insane.

Launch arguments can be found here:
https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg04012.html,
also I am re-sending the patch since I found that I missed comma in
last public version. The issue is specific to at least W2k8R2. If
webkit is stood idle for some time, it looks like Windows timer is
falling back to defaults and migration issue will not appear. Bug has
floating nature by itself, so it is just matter of interest if it can
reappear on others` setup.

pbonzini-ioapic-3.10.patch
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