[Qemu-devel] virtio 1.0 state?

[Qemu-devel] virtio 1.0 state?

[Gerd Hoffmann]

  Hi,

Where we are in terms of virtio 1.0 support in qemu?

There hasn't been much activity in mst's virtio-1.0 branch recently, at
least not in the public version of it.  And it doesn't rebase easily to
latest master any more ;(

What are the blocking issues?  Anything I can do to speed up things?
Any chance we can get the core changes merged (64bit features for
example), even if virtio 1.0 support for virtio-pci is not ready yet?

cheers,
  Gerd

Re: [Qemu-devel] virtio 1.0 state?

[Cornelia Huck]

On Fri, 22 May 2015 15:56:13 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

>   Hi,
> 
> Where we are in terms of virtio 1.0 support in qemu?
> 
> There hasn't been much activity in mst's virtio-1.0 branch recently, at
> least not in the public version of it.  And it doesn't rebase easily to
> latest master any more ;(

FWIW, an untested branch with the virtio-1.0 patches + some of my
virtio-1.0 stuff on top rebased against current master can be found
here:

git://github.com/cohuck/qemu virtio-1

> 
> What are the blocking issues?  Anything I can do to speed up things?
> Any chance we can get the core changes merged (64bit features for
> example), even if virtio 1.0 support for virtio-pci is not ready yet?

The main issues currently are feature bit handling (legacy vs.
transitional vs. modern) and migration. A prereq for fixing the first
is moving host feature bits out of the transport, for which I have a
patch floating around. The rest needs more thought before we can
proceed, I fear.

Re: [Qemu-devel] virtio 1.0 state?

[Gerd Hoffmann]

On Di, 2015-05-26 at 11:10 +0200, Cornelia Huck wrote:
> On Fri, 22 May 2015 15:56:13 +0200
> Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
> >   Hi,
> > 
> > Where we are in terms of virtio 1.0 support in qemu?
> > 
> > There hasn't been much activity in mst's virtio-1.0 branch recently, at
> > least not in the public version of it.  And it doesn't rebase easily to
> > latest master any more ;(
> 
> FWIW, an untested branch with the virtio-1.0 patches + some of my
> virtio-1.0 stuff on top rebased against current master can be found
> here:
> 
> git://github.com/cohuck/qemu virtio-1

Thanks.

> > 
> > What are the blocking issues?  Anything I can do to speed up things?
> > Any chance we can get the core changes merged (64bit features for
> > example), even if virtio 1.0 support for virtio-pci is not ready yet?
> 
> The main issues currently are feature bit handling (legacy vs.
> transitional vs. modern) and migration. A prereq for fixing the first
> is moving host feature bits out of the transport, for which I have a
> patch floating around. The rest needs more thought before we can
> proceed, I fear.

So, with the 2.4 schedule just announced it doesn't sound like very
realistic that we'll have virtio 1.0 support in qemu 2.4.

That kind-of ruins my plans to have virtio-input and virtio-gpu as
non-transitional devices in qemu 2.4 :(

cheers,
  Gerd

Re: [Qemu-devel] virtio 1.0 state?

[Gerd Hoffmann]

On Di, 2015-05-26 at 11:10 +0200, Cornelia Huck wrote:
> On Fri, 22 May 2015 15:56:13 +0200
> Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
> >   Hi,
> > 
> > Where we are in terms of virtio 1.0 support in qemu?
> > 
> > There hasn't been much activity in mst's virtio-1.0 branch recently, at
> > least not in the public version of it.  And it doesn't rebase easily to
> > latest master any more ;(
> 
> FWIW, an untested branch with the virtio-1.0 patches + some of my
> virtio-1.0 stuff on top rebased against current master can be found
> here:
> 
> git://github.com/cohuck/qemu virtio-1
> 
> > 
> > What are the blocking issues?  Anything I can do to speed up things?
> > Any chance we can get the core changes merged (64bit features for
> > example), even if virtio 1.0 support for virtio-pci is not ready yet?
> 
> The main issues currently are feature bit handling (legacy vs.
> transitional vs. modern) and migration. A prereq for fixing the first
> is moving host feature bits out of the transport, for which I have a
> patch floating around.

Have a pointer to that patch?

> The rest needs more thought before we can
> proceed, I fear.

Care to explain what the issues are in detail (mailing list pointers are
fine) and where I could possibly help?  I'm following virtio discussions
very briefly only, so I'm not fully up-to-date ...

I havn't really looked into any transport but pci, so I suspect /me
helping with migration would be more effective than looking into the
feature bit issues, especially as you started working on that
already ...

cheers,
  Gerd

Re: [Qemu-devel] virtio 1.0 state?

[Cornelia Huck]

On Thu, 28 May 2015 12:29:17 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

> On Di, 2015-05-26 at 11:10 +0200, Cornelia Huck wrote:
> > On Fri, 22 May 2015 15:56:13 +0200
> > Gerd Hoffmann <kraxel@redhat.com> wrote:
> > 
> > >   Hi,
> > > 
> > > Where we are in terms of virtio 1.0 support in qemu?
> > > 
> > > There hasn't been much activity in mst's virtio-1.0 branch recently, at
> > > least not in the public version of it.  And it doesn't rebase easily to
> > > latest master any more ;(
> > 
> > FWIW, an untested branch with the virtio-1.0 patches + some of my
> > virtio-1.0 stuff on top rebased against current master can be found
> > here:
> > 
> > git://github.com/cohuck/qemu virtio-1
> > 
> > > 
> > > What are the blocking issues?  Anything I can do to speed up things?
> > > Any chance we can get the core changes merged (64bit features for
> > > example), even if virtio 1.0 support for virtio-pci is not ready yet?
> > 
> > The main issues currently are feature bit handling (legacy vs.
> > transitional vs. modern) and migration. A prereq for fixing the first
> > is moving host feature bits out of the transport, for which I have a
> > patch floating around.
> 
> Have a pointer to that patch?

See https://marc.info/?l=qemu-devel&m=143265090821145&w=2.

> 
> > The rest needs more thought before we can
> > proceed, I fear.
> 
> Care to explain what the issues are in detail (mailing list pointers are
> fine) and where I could possibly help?  I'm following virtio discussions
> very briefly only, so I'm not fully up-to-date ...

See e.g. https://marc.info/?l=qemu-devel&m=143144377121085&w=2 and
follow-on. The virtio-1 branch has some "XXX: migration|virtio-1"
comments as well.

> 
> I havn't really looked into any transport but pci, so I suspect /me
> helping with migration would be more effective than looking into the
> feature bit issues, especially as you started working on that
> already ...

Some of the migration issues are intertwined with the feature bit
changes, but IIRC there was more.

I don't know if there are pci-specific issues as well, as I mostly look
at ccw.

Re: [Qemu-devel] virtio 1.0 state?

[Michael S. Tsirkin]

On Thu, May 28, 2015 at 01:06:14PM +0200, Cornelia Huck wrote:
> On Thu, 28 May 2015 12:29:17 +0200
> Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
> > On Di, 2015-05-26 at 11:10 +0200, Cornelia Huck wrote:
> > > On Fri, 22 May 2015 15:56:13 +0200
> > > Gerd Hoffmann <kraxel@redhat.com> wrote:
> > > 
> > > >   Hi,
> > > > 
> > > > Where we are in terms of virtio 1.0 support in qemu?
> > > > 
> > > > There hasn't been much activity in mst's virtio-1.0 branch recently, at
> > > > least not in the public version of it.  And it doesn't rebase easily to
> > > > latest master any more ;(
> > > 
> > > FWIW, an untested branch with the virtio-1.0 patches + some of my
> > > virtio-1.0 stuff on top rebased against current master can be found
> > > here:
> > > 
> > > git://github.com/cohuck/qemu virtio-1
> > > 
> > > > 
> > > > What are the blocking issues?  Anything I can do to speed up things?
> > > > Any chance we can get the core changes merged (64bit features for
> > > > example), even if virtio 1.0 support for virtio-pci is not ready yet?
> > > 
> > > The main issues currently are feature bit handling (legacy vs.
> > > transitional vs. modern) and migration. A prereq for fixing the first
> > > is moving host feature bits out of the transport, for which I have a
> > > patch floating around.
> > 
> > Have a pointer to that patch?
> 
> See https://marc.info/?l=qemu-devel&m=143265090821145&w=2.
> 
> > 
> > > The rest needs more thought before we can
> > > proceed, I fear.
> > 
> > Care to explain what the issues are in detail (mailing list pointers are
> > fine) and where I could possibly help?  I'm following virtio discussions
> > very briefly only, so I'm not fully up-to-date ...
> 
> See e.g. https://marc.info/?l=qemu-devel&m=143144377121085&w=2 and
> follow-on. The virtio-1 branch has some "XXX: migration|virtio-1"
> comments as well.
> 
> > 
> > I havn't really looked into any transport but pci, so I suspect /me
> > helping with migration would be more effective than looking into the
> > feature bit issues, especially as you started working on that
> > already ...
> 
> Some of the migration issues are intertwined with the feature bit
> changes, but IIRC there was more.
> 
> I don't know if there are pci-specific issues as well, as I mostly look
> at ccw.

I think the biggest issue for pci is the inter-play between
DRIVER_OK and pci bus master.

-- 
MST