On Tue, 28 Jun 2016 08:22:05 +0200 Peter Lieven <p...@kamp.de> wrote:
> Am 27.06.2016 um 17:09 schrieb Cornelia Huck: > > On Mon, 27 Jun 2016 11:44:47 +0200 > > Peter Lieven <p...@kamp.de> wrote: > > > >> Hi, with the above patch applied: > >> > >> commit 9f06e71a567ba5ee8b727e65a2d5347fd331d2aa > >> Author: Cornelia Huck <cornelia.h...@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? > > > > 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 Nothing really exciting there, maybe a timing issue triggered by the iscsi backing? > > Have you the possiblity to install Ubuntu 14.04 on an iSCSI target? No, I don't have any iscsi target available. > > Let me know if you need further information. Maybe the regression is an > incompatiblity between the iSCSI driver and ioeventfd? Running in gdb and looking at the backchains may be helpful. Or checking in a guest dump whether there's any hang there instead. (Does this happen with guests other than Ubuntu 14.04, maybe with a similar kernel level?)