Re: [Qemu-devel] [Crucial bug] Qemu-2.0.0 do not support virtio-net hot plug/unplug exceed two times

["Andreas Färber" <afaerber@suse.de>]

Am 06.05.2014 17:02, schrieb Andreas Färber:
> Am 06.05.2014 16:08, schrieb Gonglei (Arei):
>>> -----Original Message-----
>>> From: Andreas Färber [mailto:afaerber@suse.de]
>>> Sent: Tuesday, May 06, 2014 9:58 PM
>>> To: Gonglei (Arei)
>>> Cc: Markus Armbruster; Hani Benhabiles; Peter Maydell; Paolo Bonzini;
>>> Michael S. Tsirkin; qemu-devel@nongnu.org
>>> Subject: Re: [Qemu-devel] [Crucial bug] Qemu-2.0.0 do not support virtio-net
>>> hot plug/unplug exceed two times
>>>
>>>>> Sounds like the acpiphp kernel module is not loaded inside the guest?
>>>>>
>>>> OMG, thank you so much. Good catch.
>>>
>>> In that case check your /etc/modprobe.conf file in the SLES guest. From
>>> at least SLES 11 SP2 on you should have an entry like this (here SP3):
>>>
>>> alias dmi:bvnQEMU:bvrQEMU:* acpiphp
>>>
>>> The exact values changed between SeaBIOS versions at some point.
>>>
>> Yes, I find the entry in /etc/modprobe.conf file. But I don't understand it:
>>
>> # QEMU/KVM can handle ACPI Hotplugging
>> alias dmi:bvnQEMU:bvrQEMU:* acpiphp
>>
>> Why not the SLSE OS auto load the acpiphp module when it's booting?
> 
> This entry is what's supposed to trigger the auto-load on our KVM. :)
> 
> Like I said above, it depends on the (Sea)BIOS, and you can verify your
> values by running
> 
> udevadm monitor --property
> 
> and while it's monitoring, running
> 
> udevadm trigger
> 
> On a recent QEMU I then see
> 
> KERNEL[761.415335] change   /devices/virtual/dmi/id (dmi)
> ACTION=change
> DEVPATH=/devices/virtual/dmi/id
> MODALIAS=dmi:bvnBochs:bvrBochs;bd01/01/2011:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-2.0:cvnBochs:ct1:cvr:
> SEQNUM=2896
> SUBSYSTEM=dmi
> 
> So with the SeaBIOS blob from qemu.git,
> 
> alias dmi:bvnBochs:bvrBochs:* acpiphp
> 
> would be needed. Once you add it to modprobe.conf I would expect the
> next `udevadm trigger` (or reboot) to auto-load the module again.

SLES 11 SP2 kernels since 2012
(https://bugzilla.novell.com/show_bug.cgi?id=754391) and SP3 should not
need the modprobe.conf entry for "Bochs", since the DMI match was added
to the module itself. So it sounds as if the kernel package is not
up-to-date?

If you do see this problem with a fully-updated SLES guest (kernel-* and
module-init-tools packages), please let us know.

Regards,
Andreas

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