libvirt users - Dec 2017 - Question about disabling UFO on guest

Hello everyone,

I would like to ask a question regarding to disable UFO of virtio vNIC in
my guest. I have read the document at https://libvirt.org/formatdomain.html


*host*

The csum, gso, tso4, tso6, ecn and ufo attributes with possible
values on and off can be used to turn off host offloading options. By
default, the supported offloads are enabled by QEMU. *Since 1.2.9 (QEMU
only)* The mrg_rxbuf attribute can be used to control mergeable rx buffers
on the host side. Possible values are on (default) and off. *Since 1.2.13
(QEMU only)*

*guest*

The csum, tso4, tso6, ecn and ufo attributes with possible
values on and off can be used to turn off guest offloading options. By
default, the supported offloads are enabl

ed by QEMU.
*Since 1.2.9 (QEMU only)*


Then I disabled UFO on my vNIC on guest as the following configuration

<devices>

  <interface type='network'>

    <source network='default'/>

    <target dev='vnet1'/>

    <model type='virtio'/>

    <driver name='vhost' txmode='iothread'
ioeventfd='on' event_idx='off'
queues='5' rx_queue_size='256' tx_queue_size='256'>

      *<host gso='off' ufo='off' />*

      *<guest ufo='off'/>*

    </driver>



  </interface>

</devices>


Then I reboot my node to get the change effect and it works. However, can I
disable the UFO without touching the host OS? or it always has to disable
on both host and guest like that?


Thanks,

Brs,

Natsu

Hi Bao,

Then I reboot my node to get the change effect and it works. However, can I
disable the UFO without touching the host OS? or it always has to disable
on both host and guest like that?
As I know, if you want to disable both for receive and transmit,  it can
only be turned off via 'host_ufo=off,gso=off,guest_ufo=off'.
<driver>
<host gso='off' ufo='off'/> ===> for receive
<guest ufo='off'/> ====> for transmit
 </driver>

Reference: https://bugzilla.redhat.com/show_bug.cgi?id=1387477#c4


-------
Best Regards,
Yalan Zhang
IRC: yalzhang


On Sun, Dec 24, 2017 at 1:57 AM Bao Nguyen <baondt@gmail.com> wrote:
> Hello everyone,
>
> I would like to ask a question regarding to disable UFO of virtio vNIC in
> my guest. I have read the document at
> https://libvirt.org/formatdomain.html
>
>
> *host*
>
> The csum, gso, tso4, tso6, ecn and ufo attributes with possible
> values on and off can be used to turn off host offloading options. By
> default, the supported offloads are enabled by QEMU. *Since 1.2.9 (QEMU
> only)* The mrg_rxbuf attribute can be used to control mergeable rx
> buffers on the host side. Possible values are on (default) and off. *Since
> 1.2.13 (QEMU only)*
>
> *guest*
>
> The csum, tso4, tso6, ecn and ufo attributes with possible
> values on and off can be used to turn off guest offloading options. By
> default, the supported offloads are enabl
>
> ed by QEMU.
> *Since 1.2.9 (QEMU only)*
>
>
> Then I disabled UFO on my vNIC on guest as the following configuration
>
> <devices>
>
>   <interface type='network'>
>
>     <source network='default'/>
>
>     <target dev='vnet1'/>
>
>     <model type='virtio'/>
>
>     <driver name='vhost' txmode='iothread'
ioeventfd='on' event_idx='off'
> queues='5' rx_queue_size='256'
tx_queue_size='256'>
>
>       *<host gso='off' ufo='off' />*
>
>       *<guest ufo='off'/>*
>
>     </driver>
>
>
>
>   </interface>
>
> </devices>
>
>
> Then I reboot my node to get the change effect and it works. However, can
> I disable the UFO without touching the host OS? or it always has to disable
> on both host and guest like that?
>
>
> Thanks,
>
> Brs,
>
> Natsu
>
>
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> libvirt-users mailing list
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