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Date: Tue, 28 Jun 2016 10:03:21 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
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	<20160627170938.04a7a13c.cornelia.huck@de.ibm.com>
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Subject: Re: [Qemu-devel] Regression: virtio-pci: convert to ioeventfd
 callbacks
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To: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Peter Lieven <pl@kamp.de>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, famz@redhat.com, stefanha@redhat.com

On Mon, Jun 27, 2016 at 05:09:38PM +0200, Cornelia Huck wrote:
> On Mon, 27 Jun 2016 11:44:47 +0200
> Peter Lieven <pl@kamp.de> wrote:
> 
> > Hi, with the above patch applied:
> > 
> > commit 9f06e71a567ba5ee8b727e65a2d5347fd331d2aa
> > Author: Cornelia Huck <cornelia.huck@de.ibm.com>
> > Date:   Fri Jun 10 11:04:12 2016 +0200
> > 
> >      virtio-pci: convert to ioeventfd callbacks
> > 
> > a Ubuntu 14.04 VM freezes at startup when blk-mq is set up - even if there is only one queue.
> 
> OK, I played around a bit with Stefan's block branch rebased upon
> current master (and the conflict fixed up)... and I can't seem to hit
> any error with virtio-ccw (will see if I find time to play around with
> virtio-pci; but unless I've messed up, this should be the same code
> path). VIRTIO_BLK_F_MQ is correctly negotiated if num_queues > 1, and I
> can use the disk.
> 
> So, two questions:
> - Which branch are you using? Any chance of a mis-merge there?
> - Can you share the interesting portion of your command line?


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?


-- 
MST