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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: |
Fri, 13 Jul 2018 06:28:39 +0300 |
On Thu, Jul 12, 2018 at 09:20:41PM -0400, Samudrala, Sridhar wrote:
> On 7/12/2018 6:19 PM, Siwei Liu wrote:
> > On Thu, Jul 12, 2018 at 2:00 PM, Michael S. Tsirkin <address@hidden> wrote:
> > > On Thu, Jul 12, 2018 at 01:52:53PM -0700, Siwei Liu wrote:
> > > > The definition is incomplete due to lack of spec. There's no "host"
> > > > part defined yet in the host-guest interface. If match by MAC is an
> > > > interface, the same must be done on the host(device) side as well,
> > > > which has been agreed not the way to go. However, I don't think that's
> > > > what the author intends to do by interpreting his QEMU patch - it
> > > > missed the other parts as well, such as the feature negotiation and
> > > > how it interacts with the paired device.
> > > >
> > > > What I said is that match by MAC is just a guest implementation that
> > > > one can change at any time. We now have the group ID on QEMU, why
> > > > still sticking to matching by MAC? It shoulnd't be a host-guest
> > > > interface in the first place anyway.
> > > I think that match by MAC is a simple portable way to match devices.
> > > E.g. it will work seamlessly with niche things like zPCI. However
> > That's a good point. I'm not sure if it's a valid assumption that zPCI
> > should always use the same MAC address as that of virtio. Someone
> > who's more familiar with the use case may decide and work on that. It
> > means VFIO device has to take in the MAC address as an identifier to
> > the "-device vfio-pci,.." QEMU option. I think there's no point to
> > match device using group ID in QEMU while using MAC in the guest.
> > Based on that assumption, I'd go with making VIRTIO_NET_F_STANDBY to
> > match device based on group ID, while someone may come up with another
> > feature bit later, say VIRTIO_NET_F_STANDBY_BY_MAC when its QEMU
> > support is available. Would it make sense?
>
> VIRTIO_NET_F_STANDBY as defined in the guest virtio_net driver supports match
> by MAC address. I think we should add support for this feature bit in QEMU.
> If submitting a patch to update the spec is a pre-requisite to add this
> feature bit to QEMU, i can do that.
It's not strictly a prerequisite but we need it in spec all the same, so
pls do that.
> As far as i understand, group id patches to QEMU are still under review.
> Matching by group ID can be another feature bit that could support matching
> by group id as well as MAC.
>
>
> > -Siwei
> >
> > > there are other niche use-cases that aren't addressed by match by MAC
> > > such as PF pass-through as a primary, and the pci bridge trick addresses
> > > that at cost of some portability.
> > >
> > > So I see no issues supporting both mechanisms, but others on the TC
> > > might feel differently.
> > >
> > > --
> > > MST
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., (continued)
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., si-wei liu, 2018/07/09
- Re: [Qemu-devel] [PATCH v3 0/3] Use of unique identifier for pairing virtio and passthrough devices..., Michael S. Tsirkin, 2018/07/09
- 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] [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 <=
- 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, 2018/07/12
- 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