[libvirt] [RFC PATCH v2 REBASE 00/18] Introduce vGPU mdev framework to libvirt

[yonglihe]

On 2017年03月16日 22:41, Erik Skultety wrote:
>> [2] 2005
>> ubuntu at z-nuc-11:~/vgpu-meta/libvirt-stage$
>> ***************************************************
>> start libvirt-d
>> 2017-03-09 19:04:57.211+0000: 2059: info : libvirt version: 3.1.0
>> 2017-03-09 19:04:57.211+0000: 2059: info : hostname: z-nuc-11.maas
>> 2017-03-09 19:04:57.211+0000: 2059: error : qemuMonitorOpenUnix:367 :
>> failed to connect to monitor socket: No such process
>> 2017-03-09 19:04:57.213+0000: 2059: error :
>> virMediatedDeviceGetIOMMUGroupDev:153 : internal error: IOMMU group file /sys/bus/mdev/devices/894f3983-1a36-42b3-b52c-1024aca216be/iommu_group
>> is not a symlink
> When I saw this error message for the first time in the original thread, I got
> confused, since this just checks whether the symlink exists, if it
> doesn't, the vfio device probably also doesn't exist (but take this with a
> grain of salt, I haven't investigated that deep) and libvirt needs it to pass
> it onto qemu command line. I hit this issue once by accident in the past and at
> that time I didn't understand what caused it, but after a reboot it was gone.
> So seeing it here it caught my eye and I investigated it last week. What I
> found out was that it's caused by the vfio-mdev module not being loaded
> automatically as a dependency. I solved it by autoloading the module on system
> boot. So this is not a libvirt issue, but just for a reference, there is a BZ
> on this [1].
it's does not show up every time. might be my bad.
>
>> 2017-03-09 19:04:57.213+0000: 2003: info : libvirt version: 3.1.0
>> 2017-03-09 19:04:57.213+0000: 2003: info : hostname: z-nuc-11.maas
>> 2017-03-09 19:04:57.213+0000: 2003: error : virNetSocketReadWire:1800 :
>> End of file while reading data: Input/output error
> I suppose this corresponds to the problem above, do you hit this error if you
> work around the vfio-mdev module problem described above?
>
>> the screen call trace while start the VM (same for Ubuntu, Win10 etc) ======================================================
>>
>> ubuntu at z-nuc-11:~/vgpu-meta/libvirt-stage$ myvirsh start vgpu-ubuntu
>> 2017-03-09 19:06:50.483+0000: 2232: info : libvirt version: 3.1.0
>> 2017-03-09 19:06:50.483+0000: 2232: info : hostname: z-nuc-11.maas
>> 2017-03-09 19:06:50.483+0000: 2232: warning : qemuDomainObjTaint:4056 :
>> Domain id=1 name='vgpu-ubuntu' uuid=972b5e38-0437-11e7-8f97-d36dba74552d
>> is tainted: high-privileges
>> 2017-03-09 19:06:50.819+0000: 2204: info : libvirt version: 3.1.0
>> 2017-03-09 19:06:50.819+0000: 2232: warning : virDomainAuditHostdev:456
>> : Unexpected hostdev type while encoding audit message: 4
> This one's interesting, again, are you able to hit the error when you work
> around the missing vfio-mdev module? I'll have a look at this if you actually
> can hit the error, even if the XML is correct.
the module should be there,  the domain is running and virtual gpu is 
working.

ubuntu at z-nuc-11:~/vgpu-meta/libvirt-stage$ sudo lsmod| grep mdev
vfio_mdev              16384  1
mdev                   20480  2 kvmgt,vfio_mdev
vfio                   28672  6 vfio_iommu_type1,kvmgt,vfio_mdev

on the v3, the trace still there. refer to my "test by" email on mdev-next.

Regards
Yongli He
>
> I posted v3 of the series and also created a new branch 'mdev-next' on my
> github [2]. I dropped the attribute 'type' from the source address element, so
> follow the example in the updated docs.
>
> Thanks for giving it a try.
> Erik
>
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1420572
> [2] https://github.com/eskultety/libvirt/commits/mdev-next