Re: [Qemu-devel] Regression: virtio-pci: convert to ioeventfd callbacks

[Peter Lieven]

Am 27.06.2016 um 17:09 schrieb Cornelia Huck:
> On Mon, 27 Jun 2016 11:44:47 +0200
> Peter Lieven <address@hidden> wrote:
>
> > Hi, with the above patch applied:
> >
> > commit 9f06e71a567ba5ee8b727e65a2d5347fd331d2aa
> > Author: Cornelia Huck <address@hidden>
> > 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?

Hi Cornelia,

sorry I should have been a little more precise. I am using current master for 
git.qemu.org.

I tried around and I can only reproduce the regression with iSCSI *and* 
dataplane enabled.
Here is the reproducing commandline for me.

./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -nodefaults -drive if=none,format=raw,file=iscsi://172.21.200.56/iqn.2001-05.com.equallogic:0-8a0906-98f384e0a-7d2004ee0a85767a-00lieven-test/0,cache=none,aio=native,id=disk0 -object iothread,id=iothread0 
-device virtio-blk-pci,drive=disk0,iothread=iothread0 -vga vmware -monitor stdio

Have you the possiblity to install Ubuntu 14.04 on an iSCSI target?

Let me know if you need further information. Maybe the regression is an 
incompatiblity between the iSCSI driver and ioeventfd?

Thanks,
Peter