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Date: Tue, 28 Jun 2016 09:42:45 +0200
From: Cornelia Huck <cornelia.huck@de.ibm.com>
In-Reply-To: <20160628100152-mutt-send-email-mst@redhat.com>
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Subject: Re: [Qemu-devel] Regression: virtio-pci: convert to ioeventfd
 callbacks
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To: "Michael S. Tsirkin" <mst@redhat.com>, Peter Lieven <pl@kamp.de>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, famz@redhat.com, stefanha@redhat.com

On Tue, 28 Jun 2016 10:03:21 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> I notice cleanup is a bit weird:
> 
>         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
>         k->ioeventfd_assign(proxy, notifier, n, assign);
>         event_notifier_cleanup(notifier);
> 
> I think virtio_queue_set_host_notifier_fd_handler should happen
> after ioeventfd_assign for symmetry with init?

Looking at the pre-rework code, ccw used the order now in common code,
while pci and mmio used the order you suggest.

"Switch the handler back, then unassign the transport's ioeventfd
backing" made more sense to me (regardless of symmetry) - but we might
lose a notification?

Peter: Can you check whether your problem goes away if you switch the
two lines around?