From: "Michael S. Tsirkin" <mst@redhat•com>
To: Siwei Liu <loseweigh@gmail•com>
Cc: "Samudrala, Sridhar" <sridhar.samudrala@intel•com>,
Alexander Duyck <alexander.duyck@gmail•com>,
Jiri Pirko <jiri@resnulli•us>,
Stephen Hemminger <stephen@networkplumber•org>,
David Miller <davem@davemloft•net>,
Netdev <netdev@vger•kernel.org>,
virtio-dev@lists•oasis-open.org, "Brandeburg,
Jesse" <jesse.brandeburg@intel•com>,
"Duyck, Alexander H" <alexander.h.duyck@intel•com>,
Jakub Kicinski <kubakici@wp•pl>
Subject: Re: Re: [PATCH v4 2/2] virtio_net: Extend virtio to use VF datapath when available
Date: Sun, 4 Mar 2018 06:00:07 +0200 [thread overview]
Message-ID: <20180304055802-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CADGSJ223dPtspMBcT8RPWsVYUbfMhVHU8FvwURQVDi2aFY+6Tg@mail.gmail.com>
On Fri, Mar 02, 2018 at 02:26:48PM -0800, Siwei Liu wrote:
> On Fri, Mar 2, 2018 at 1:31 PM, Michael S. Tsirkin <mst@redhat•com> wrote:
> > On Fri, Mar 02, 2018 at 12:44:56PM -0800, Siwei Liu wrote:
> >> On Fri, Mar 2, 2018 at 12:10 PM, Michael S. Tsirkin <mst@redhat•com> wrote:
> >> > On Fri, Mar 02, 2018 at 11:52:27AM -0800, Samudrala, Sridhar wrote:
> >> >>
> >> >>
> >> >> On 3/2/2018 11:41 AM, Michael S. Tsirkin wrote:
> >> >> > On Fri, Mar 02, 2018 at 07:26:25AM -0800, Alexander Duyck wrote:
> >> >> > > The design limits things to a 1:1 relationship since we just have the
> >> >> > > child and backup pointers, but I don't think I am seeing exception
> >> >> > > handling to prevent us from overwriting the child pointers so there
> >> >> > > may be a leak there.
> >> >> > >
> >> >> > > Thanks.
> >> >> > >
> >> >> > > - Alex
> >> >> > In fact maintaining a list in that case would be nicer, and
> >> >> > just use an arbitrary one.
> >> >> > E.g. one can see how a user wanting to swap device 1 for device 2
> >> >> > might first add device 2 with same MAC then drop device 1.
> >> >>
> >> >> It should be possible to swap VF1 with VF2 by
> >> >> 1.- enabling virtio link
> >> >> 2.- unplugging VF1
> >> >> 3.- plugging VF2
> >> >> 4.- disabling virtio link
> >> >>
> >> >
> >> > True, but it isn't hard to avoid breakage if user
> >> > swapped steps 2 and 3. No need to make it more
> >> > fragile that it has to be.
> >>
> >> The migration case, VF2 is associated with another PF on another
> >> machine (destination), I wonder how it is possible.
> >
> > E.g. you want to remove the PF so you unplug the VF
> > then add another VF of the same PF.
> >
> >> Even with local plugging of VF2 on the same PF, the MAC address
> >> requirement (VF1's == VF2's) would fail the MAC address assignment on
> >> VF2.
> >>
> >> -Siwei
> >
> > Why would it fail? These are separate cards.
>
> OK. I realized that you may talk about assigning a VF on a diffferent
> PF (VF1 on PF1 while VF2 on PF2). And we might assign a pass-through
> device rather than a VF. Yes, it's indeed possible that may happen but
> I take it as a further step down (another patch maybe) as it would
> involve changes to notify the network with gratuituious ARP and/or
> unsolicited ND advertisement of the MAC address association with the
> new port.
>
> -Siwei
Interesting point. I guess that's a limitation in the curent patch then:
virtio and PT device must be connected to the same physical NIC.
Worth documenting.
> >
> >> >
> >> > --
> >> > MST
> >> >
> >> > ---------------------------------------------------------------------
> >> > To unsubscribe, e-mail: virtio-dev-unsubscribe@lists•oasis-open.org
> >> > For additional commands, e-mail: virtio-dev-help@lists•oasis-open.org
> >> >
next prev parent reply other threads:[~2018-03-04 4:00 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-01 20:08 [PATCH v4 0/2] Enable virtio_net to act as a backup for a passthru device Sridhar Samudrala
2018-03-01 20:08 ` [PATCH v4 1/2] virtio_net: Introduce VIRTIO_NET_F_BACKUP feature bit Sridhar Samudrala
2018-03-01 20:08 ` [PATCH v4 2/2] virtio_net: Extend virtio to use VF datapath when available Sridhar Samudrala
2018-03-02 8:36 ` Jiri Pirko
2018-03-02 15:26 ` Alexander Duyck
2018-03-02 16:20 ` Jiri Pirko
2018-03-02 16:37 ` Samudrala, Sridhar
2018-03-02 17:06 ` Alexander Duyck
2018-03-02 19:42 ` Michael S. Tsirkin
2018-03-02 20:49 ` Siwei Liu
2018-03-03 11:31 ` Jiri Pirko
2018-03-03 18:04 ` Alexander Duyck
2018-03-03 21:25 ` Jiri Pirko
2018-03-04 0:26 ` Alexander Duyck
2018-03-04 7:13 ` Jiri Pirko
2018-03-04 18:24 ` Alexander Duyck
2018-03-04 18:50 ` Jiri Pirko
2018-03-04 21:54 ` Samudrala, Sridhar
2018-03-04 21:58 ` Alexander Duyck
2018-03-05 9:21 ` Jiri Pirko
2018-03-05 16:11 ` Stephen Hemminger
2018-03-05 22:30 ` Jiri Pirko
2018-03-05 22:47 ` Alexander Duyck
2018-03-06 3:15 ` Stephen Hemminger
2018-03-06 19:08 ` Alexander Duyck
2018-03-06 22:59 ` Jiri Pirko
2018-03-06 23:27 ` Alexander Duyck
2018-03-07 2:38 ` Michael S. Tsirkin
2018-03-07 17:50 ` Alexander Duyck
2018-03-07 18:06 ` Stephen Hemminger
2018-03-07 18:55 ` Alexander Duyck
2018-03-07 20:11 ` Michael S. Tsirkin
2018-03-12 18:47 ` Samudrala, Sridhar
2018-03-02 19:41 ` Michael S. Tsirkin
2018-03-02 19:52 ` Samudrala, Sridhar
2018-03-02 20:10 ` Michael S. Tsirkin
2018-03-02 20:44 ` Siwei Liu
2018-03-02 20:56 ` Samudrala, Sridhar
2018-03-02 21:33 ` Michael S. Tsirkin
2018-03-02 21:31 ` Michael S. Tsirkin
2018-03-02 22:26 ` Siwei Liu
2018-03-04 4:00 ` Michael S. Tsirkin [this message]
2018-03-02 21:11 ` Siwei Liu
2018-03-02 21:36 ` Michael S. Tsirkin
2018-03-02 23:56 ` Siwei Liu
2018-03-04 4:04 ` Michael S. Tsirkin
2018-03-12 21:53 ` Siwei Liu
2018-03-02 23:12 ` Samudrala, Sridhar
2018-03-03 0:09 ` Siwei Liu
2018-03-12 20:12 ` Jiri Pirko
2018-03-12 20:58 ` Samudrala, Sridhar
2018-03-12 21:08 ` Jiri Pirko
2018-03-14 0:36 ` Samudrala, Sridhar
2018-03-14 0:54 ` Stephen Hemminger
2018-03-14 15:45 ` Jiri Pirko
2018-03-12 22:44 ` Siwei Liu
2018-03-14 0:28 ` Samudrala, Sridhar
2018-03-14 0:44 ` Michael S. Tsirkin
2018-03-14 4:50 ` Siwei Liu
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