Re: [Qemu-devel] [Spice-devel] Vdagent not working on xen linux hvm DomUs

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Dec 17, 2013 at 05:01:58PM +0100, Fabio Fantoni wrote:
> Il 13/12/2013 17:22, Wei Liu ha scritto:
> >On Fri, Dec 13, 2013 at 10:51:01AM +0100, Fabio Fantoni wrote:
> >>Il 12/12/2013 17:05, Fabio Fantoni ha scritto:
> >>>Il 12/12/2013 16:23, Wei Liu ha scritto:
> >>>>On Thu, Dec 12, 2013 at 02:10:23PM +0100, Fabio Fantoni wrote:
> >>>>[...]
> >>>>>I did some other tests, I narrowed down the commit range to
> >>>>>the one between:
> >>>>>
> >>>>>commit c9fea5d701f8fd33f0843728ec264d95cee3ed37 Mon, 22 Jul 2013
> >>>>>15:14:18 (Merge remote-tracking branch 'bonzini/iommu-for-anthony')
> >>>>>where there is virtio net regression with xen
> >>>>>
> >>>>>and
> >>>>>
> >>>>>commit    962b03fcf509db25c847aa67c4eff574c240dcfe Thu, 4 Jul 2013
> >>>>>15:42:43 +0000 (xen: Mark fixed platform I/O as unaligned)
> >>>>>where virtio net is working
> >>>>>
> >>>>>I also tested:
> >>>>>commit 2562becfc126ed7678c662ee23b7c1fe135d8966 Mon, 15 Jul 2013
> >>>>>19:02:41 +0000
> >>>>>and
> >>>>>commit dcb117bfda5af6f6ceb7231778d36d8bce4aee93 Thu, 4 Jul 2013
> >>>>>15:42:46 +0000

bisect is pretty aggressive sometimes but there are only 300
commits in this range.
So you should be able to just try them all automatically.

It might be a good idea to start a new thread,
Cc all lists at the same time and collect the
information known so far.

Also, is MSI working for Xen generally?
Maybe it's not a virtio-only problem.

> >>>>>but qemu crashes on xl create for another error and I haven't found
> >>>>>which is the commit to apply with git cherry-pick so that I can
> >>>>>check if the virtio net regression is present.
> >>>>>
> >>>>>Can someone help me please?

> >>>>>
> >>>>>I added also qemu-devel to cc.
> >>>>>
> >>>>I did a quick test with Xen's QEMU, currently at
> >>>>
> >>>>commit 1c514a7734b7f98625a0d18d5e8ee7581f26e50c
> >>>>Merge: 79c097d 35bdc13
> >>>>Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> >>>>Date:   Tue Jun 25 11:34:24 2013 +0000
> >>>>
> >>>>     Merge remote branch 'perard/cpu-hotplug-port-v2' into
> >>>>xen-staging-master-7
> >>>>
> >>>>from git://xenbits.xen.org/qemu-upstream-unstable.git
> >>>>My guest is Squeeze with stock kernel 2.6.32.
> >>>>
> >>>>vif=['model=virtio-net-pci,bridge=xenbr0']
> >>>>
> >>>>No pci=nomsi in guest kernel command line.
> >>>>
> >>>>Everything worked fine. And /proc/interrupts shows that it's indeed
> >>>>using MSI for virtio PCI.
> >>>>
> >>>>I'm kind of confused. (And in the long run of this thread I probably
> >>>>didn't remember everything.)
> >>>>
> >>>>Wei.
> >>>I tried with "commit e16435c95be86244bd92c5c26579bd4298aa65a6
> >>>(xen_disk: mark ioreq as mapped before unmapping in error case)"
> >>>from git://xenbits.xen.org/qemu-upstream-4.3-testing.git.
> >>>There are only 4 commits difference between mine and your test.
> >>>FWIK the only other difference is domUs kernel versions, and the
> >>>msi problem is probably a regression between kernel 2.6.32 and 3.2
> >>>(the "older" domUs used in my tests was Precise with kernel 3.2).
> >>>Tomorrow I'll try also with squeeze.
> >>I tested with squeeze and with qemu 1.3.1, virtio net works also
> >>without pci=nomsi, so seems kernel regression about msi using xen
> >>(that make virtio devices not working) between versions 2.6.32 and
> >>3.2.
> >>Any idea about solve it?
> >>
> >3.2 is still old to be honest. I don't think we have the bandwidth to
> >look at it.
> >
> >It's never easy to debug problem involving several software components.
> >The right thing to do is to use a) latest stable kernel tree which is
> >still actively maintained, b) Linus's tree. Only those actively trees
> >maintained / developed people have incentive / time to look at.
> >
> >If you're using a specific distro kernel, it would be probably helpful
> >to report bug to that distro as well -- only if you're sure the bug
> >you're seeing is distro kernel's bug.
> >
> >If you really want this feature so bad. I would sugguest you try latest
> >stable kernel to see if it works. If not, you probably need to revisit
> >your requirement and look for another route to achieve your goal.
> >
> >Wei.
> 
> Thanks for your reply.
> About kernel msi regression I'll do other tests.
> Could it be useful to try this patch:
> https://bugzilla.kernel.org/attachment.cgi?id=113791
> or is it totally unrelated?
> 
> 
> 
> About the other regression (the upstream qemu 1.6 regression that
> causes qemu crash with virtio net) can someone help me please?

It might be a good idea to start a separate thread
related to this, too.


> >I did some other tests, I narrowed down the commit range to
> >the one between:
> >
> >commit c9fea5d701f8fd33f0843728ec264d95cee3ed37 Mon, 22 Jul 2013
> >15:14:18 (Merge remote-tracking branch 'bonzini/iommu-for-anthony')
> >where there is virtio net regression with xen
> >
> >and
> >
> >commit    962b03fcf509db25c847aa67c4eff574c240dcfe Thu, 4 Jul 2013
> >15:42:43 +0000 (xen: Mark fixed platform I/O as unaligned)
> >where virtio net is working
> >
> >I also tested:
> >commit 2562becfc126ed7678c662ee23b7c1fe135d8966 Mon, 15 Jul 2013
> >19:02:41 +0000
> >and
> >commit dcb117bfda5af6f6ceb7231778d36d8bce4aee93 Thu, 4 Jul 2013
> >15:42:46 +0000
> >but qemu crashes on xl create for another error and I haven't found
> >which is the commit to apply with git cherry-pick so that I can
> >check if the virtio net regression is present.
> >
> >Can someone help me please?
> 
> Thanks for any reply.