On 6/6/2018 11:52 AM, Ján Tomko wrote:
On Wed, Jun 06, 2018 at 11:17:36AM -0700, Samudrala, Sridhar wrote:
> On 6/4/2018 7:06 PM, Jason Wang wrote:
>>
>>
>> On 2018年06月05日 09:41, Samudrala, Sridhar wrote:
>>> Ping on this patch now that the kernel patches are accepted into
>>> davem's net-next tree.
>>>
https://patchwork.ozlabs.org/cover/920005/
>>>
>>>
>>> On 5/7/2018 4:09 PM, Sridhar Samudrala wrote:
>>>> This feature bit can be used by hypervisor to indicate virtio_net
>>>> device to
>>>> act as a standby for another device with the same MAC address.
>>>>
>>>> I tested this with a small change to the patch to mark the STANDBY
>>>> feature 'true'
>>>> by default as i am using libvirt to start the VMs.
>>>> Is there a way to pass the newly added feature bit 'standby' to
qemu
>>>> via libvirt
>>>> XML file?
>>>>
>>
>> Maybe you can try qemu command line passthrough:
>>
>>
https://libvirt.org/drvqemu.html#qemucommand
>
> It looks like this can be used to pass command line arguments to qemu.
> Is it possible to specify a virtio specific attribute via this method?
>
Yes, for testing purposes you should be able to do this via using QEMU's
-set command line argument:
http://blog.vmsplice.net/2011/04/how-to-pass-qemu-command-line-options.html
i.e.:
<domain type='kvm'
xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
...
<qemu:commandline>
<qemu:arg value='-set'/>
<qemu:arg value='device.net0.standby=on'/>
</qemu:commandline>
</domain>
Thanks. Will try this.
> For ex: to say mrg_rxbuf is off we can add the following line to virtio
> section of the domain xml file.
> <host mrg_rxbuf='off'/>
>
> I think libvirt needs to be extended to to support the new 'standby'
> attribute
> via this mechanism.
> Adding Liane Stump and libvirt to the CC list.
*Laine
>
> Michael,
> Can we start with getting this patch into Qemu and an update to
> libvirt to
> support the 'standby' feature so that this feature can be enabled via
> some scripts/orchestration layer for now.
>
> We could improve this solution by enhancing Qemu to do automatic
> management of the
> addition/deletion of the primary device based on feature negotiation
> as a later patch.
>
If that means the libvirt attribute would no longer be needed, I don't
see the reason to add it to libvirt in the first place.
I think we still need this attribute supported via libvirt so that a user/admin
can enable this feature via domain XML specification.