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Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifie
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices... |
Date: |
Thu, 12 Jul 2018 22:18:04 +0300 |
On Wed, Jul 11, 2018 at 11:53:44AM +0200, Cornelia Huck wrote:
> On Tue, 10 Jul 2018 17:07:37 -0700
> Siwei Liu <address@hidden> wrote:
>
> > On Mon, Jul 9, 2018 at 6:54 PM, Michael S. Tsirkin <address@hidden> wrote:
> > > On Mon, Jul 09, 2018 at 06:11:53PM -0700, si-wei liu wrote:
> > >> The plan is to enable group ID based matching in the first place rather
> > >> than
> > >> match by MAC, the latter of which is fragile and problematic.
> > >
> > > It isn't all that fragile - hyperv used same for a while, so if someone
> > > posts working patches with QEMU support but before this grouping stuff,
> > > I'll happily apply them.
> >
> > I wouldn't box the solution to very limited scenario just because of
> > matching by MAC, the benefit of having generic group ID in the first
> > place is that we save the effort of maintaining legacy MAC based
> > pairing that just adds complexity anyway. Currently the VF's MAC
> > address cannot be changed by either PF or by the guest user is a
> > severe limitation due to this. The other use case is that PT device
> > than VF would generally have different MAC than the standby virtio. We
> > shouldn't limit itself to VF specific scenario from the very
> > beginning.
>
> So, this brings me to a different concern: the semantics of
> VIRTIO_NET_F_STANDBY.
>
> * The currently sole user seems to be the virtio-net Linux driver.
> * The commit messages, code comments and Documentation/ all talk about
> matching by MAC.
> * I could not find any proposed update to the virtio spec. (If there
> had been an older proposal with a different feature name, it is not
> discoverable.)
>
> VIRTIO_NET_F_STANDBY is a host <-> guest interface. As there's no
> official spec, you can only go by the Linux implementation, and by that
> its semantics seem to be 'match by MAC', not 'match by other criteria'.
>
> How is this supposed to work in the long run?
We definitely need a spec patch for VIRTIO_NET_F_STANDBY documenting existing
semantics. Sridhar, do you plan to take a look?
--
MST
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., (continued)
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Siwei Liu, 2018/07/10
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Cornelia Huck, 2018/07/11
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Siwei Liu, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Cornelia Huck, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Siwei Liu, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Siwei Liu, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Samudrala, Sridhar, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/12
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Cornelia Huck, 2018/07/13
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices...,
Michael S. Tsirkin <=
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/09
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Siwei Liu, 2018/07/10
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/09
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/04
Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/09