Re: [libvirt] [PATCH] Ignore qemu STOP event when stopping CPUs
On Tue, 27 Apr 2010 11:20:39 +0200
jdenemar(a)redhat.com wrote:
From: Jiri Denemark <jdenemar(a)redhat.com>
With JSON qemu monitor, we get a STOP event from qemu whenever qemu
stops guests CPUs. The downside of it is that vm->state is changed to
PAUSED and a new generic paused event is send to applications. However,
when we ask qemu to stop the CPUs we are not really interested in qemu
event and we usually want to issue a more specific event.
Can you give an example? Say, "guest is suspended"?
If this is the case, something you have to consider is whether libvirt
should add high-level events on top of low-level ones.
Or, to make it more general, what should libvirt report to applications
wrt events?
By setting vm->status to PAUSED before actually sending the
request to
qemu (and resetting it back if the request fails) we can ignore the
event since the event handler does nothing when the guest is already
paused. This solution is quite hacky but unfortunately it's the best
solution which I was able to come up with and it doesn't introduce a
race condition.
You could extend the low-level driver to accept a mask of events to
be ignored.