Re: qemu-4.0.1: vhost_region_add_section:Section rounded to 0 prior to previous a0000

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Lieven <pl@kamp.de>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>
Subject: Re: qemu-4.0.1: vhost_region_add_section:Section rounded to 0 prior to previous a0000
Date: Fri, 17 Jan 2020 15:59:09 +0000	[thread overview]
Message-ID: <20200117155909.GM3209@work-vm> (raw)
In-Reply-To: <a1bf5cc0-f32d-48eb-35e4-b895458f8ffe@kamp.de>

* Peter Lieven (pl@kamp.de) wrote:
> Am 16.01.20 um 21:26 schrieb Dr. David Alan Gilbert:
> > * Peter Lieven (pl@kamp.de) wrote:
> >> Am 16.01.20 um 13:47 schrieb Peter Lieven:
> >>> Am 13.01.20 um 17:25 schrieb Peter Lieven:
> >>>> Am 09.01.20 um 19:44 schrieb Dr. David Alan Gilbert:
> >>>>> * Peter Lieven (pl@kamp.de) wrote:
> >>>>>> Am 08.01.20 um 16:04 schrieb Dr. David Alan Gilbert:
> >>>>>>> * Peter Lieven (pl@kamp.de) wrote:
> >>>>>>>> Hi,
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> I have a Qemu 4.0.1 machine with vhost-net network adapter, thats polluting the log with the above message.
> >>>>>>>>
> >>>>>>>> Is this something known? Googling revealed the following patch in Nemu (with seems to be a Qemu fork from Intel):
> >>>>>>>>
> >>>>>>>> https://github.com/intel/nemu/commit/03940ded7f5370ce7492c619dccced114ef7f56e
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> The network stopped functioning. After a live-migration the vServer is reachable again.
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> Any ideas?
> >>>>>>> What guest are you running and what does your qemu commandline look
> >>>>>>> like?
> >>>>>> Its running debian9. We have hundreds of other VMs with identical setup. Do not know why this one makes trouble.
> >>>>> Could you extract an 'info mtree' from it - particularly the
> >>>>> 'address-space: memory' near the top.
> >>>>
> >>>> Here we go:
> >>>>
> >>>>
> >>>> address-space: memory
> >>>>   0000000000000000-ffffffffffffffff (prio 0, i/o): system
> >>>>     0000000000000000-000000003fffffff (prio 0, i/o): alias ram-below-4g @pc.ram 0000000000000000-000000003fffffff
> >>>>     0000000000000000-ffffffffffffffff (prio -1, i/o): pci
> >>>>       00000000000a0000-00000000000affff (prio 2, i/o): alias vga.chain4 @vga.vram 0000000000000000-000000000000ffff
> >>>>       00000000000a0000-00000000000bffff (prio 1, i/o): vga-lowmem
> >>>
> >>> What seems special is that the RAM area is prio2. Any idea if this makes trouble?
> >>
> >> Update from my side. This happens when I have Debian 10 with XFCE when the Graphical User Interface is initialized.
> >>
> >> I see the log message when I specify -M pc-i440fx-2.9. If I obmit the machine type the error does not appear.
> > I can't persuade this to reproduce here on the images I currently have;
> > but if you can rebuild, can you try the v3 of 'Fix hyperv synic on
> > vhost' I've just posted?  It turns off the alignment code that's
> > spitting that error in vhost-kernel cases, so should go away.
> 
> Your patch also seems to fix also my issue. No more errors and the network keeps responding.

Great, can you reply to that post with a Tested-by ?

Dave

> 
> Thanks
> 
> Peter
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK