Re: [PATCH RESEND] netvsc: transfer lower device max tso size

[Cindy Lu]

On Tue, Jul 22, 2025 at 10:04 AM Cindy Lu <lulu@xxxxxxxxxx> wrote:
>
> On Tue, Jul 22, 2025 at 9:18 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> >
> > On Tue, 22 Jul 2025 09:04:20 +0800 Jason Wang wrote:
> > > On Tue, Jul 22, 2025 at 7:28 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> > > > On Fri, 18 Jul 2025 14:17:55 +0800 Cindy Lu wrote:
> > > > > Subject: [PATCH RESEND] netvsc: transfer lower device max tso size
> > > >
> > > > You say RESEND but I don't see a link to previous posting anywhere.
> >
> > Someone should respond to this part, please.
> >
> Hi Jakub,
> sorry for the confusion. I previously sent this mail
> (https://lore.kernel.org/all/20250718060615.237986-1-lulu@xxxxxxxxxx/)
> to the wrong mailing list, so I'm resended it here.
> I've also submitted a v2 of this patch:
> https://lore.kernel.org/all/20250718082909.243488-1-lulu@xxxxxxxxxx/
> Sorry again for the mix-up.
> thanks
>
> cindy
>
> > > > I'd rather we didn't extend the magic behavior of hyperv/netvsc any
> > > > further.
> > >
> > > Are you referring to the netdev coupling model of the VF acceleration?
> >
> > Yes, it tries to apply whole bunch of policy automatically in
> > the kernel.
> >
> > > > We have enough problems with it.
> > >
> > > But this fixes a real problem, otherwise nested VM performance will be
> > > broken due to the GSO software segmentation.
> >
> > Perhaps, possibly, a migration plan can be devised, away from the
> > netvsc model, so we don't have to deal with nuggets of joy like:
> > https://lore.kernel.org/all/1752870014-28909-1-git-send-email-haiyangz@xxxxxxxxxxxxxxxxxxx/

I'm also including Stephen Hemminger and Long Li in this thread and
would greatly appreciate any suggestions.

Thanks
cindy

> >