Linux Virtualization - Sep 2020 - [PATCH v3 0/6] Add virtio-iommu built-in topology

On Thu, Sep 24, 2020 at 12:02:55PM +0200, Joerg Roedel
wrote:
> On Thu, Sep 24, 2020 at 05:38:13AM -0400, Michael S. Tsirkin wrote:
> > On Thu, Sep 24, 2020 at 11:21:29AM +0200, Joerg Roedel wrote:
> > > On Thu, Sep 24, 2020 at 05:00:35AM -0400, Michael S. Tsirkin
wrote:
> > > > OK so this looks good. Can you pls repost with the minor
tweak
> > > > suggested and all acks included, and I will queue this?
> > > 
> > > My NACK still stands, as long as a few questions are open:
> > > 
> > > 	1) The format used here will be the same as in the ACPI table? I
> > > 	   think the answer to this questions must be Yes, so this leads
> > > 	   to the real question:
> > 
> > I am not sure it's a must.
> 
> It is, having only one parser for the ACPI and MMIO descriptions was one
> of the selling points for MMIO in past discussions and I think it makes
> sense to keep them in sync.
> 
> > We can always tweak the parser if there are slight differences
> > between ACPI and virtio formats.
> 
> There is no guarantee that there only need to be "tweaks" until
the
> ACPI table format is stablized.
> 
> Regards,
> 
> 	Joerg
But this has nothing to do with Linux.  There is also no guarantee that
the two committees will decide to use exactly the same format. Once one
of them sets the format in stone, we can add support for that format to
linux. If another one is playing nice and uses the same format, we can
use the same parsers. If it doesn't linux will have to follow suit.

-- 
MST

On Thu, Sep 24, 2020 at 08:41:21AM -0400, Michael S. Tsirkin
wrote:
> But this has nothing to do with Linux.  There is also no guarantee that
> the two committees will decide to use exactly the same format. Once one
> of them sets the format in stone, we can add support for that format to
> linux. If another one is playing nice and uses the same format, we can
> use the same parsers. If it doesn't linux will have to follow suit.
Or Linux decides to support only one of the formats, which would then be
ACPI.

Regards,

	Joerg

On Thu, Sep 24, 2020 at 02:50:46PM +0200, Joerg Roedel
wrote:
> On Thu, Sep 24, 2020 at 08:41:21AM -0400, Michael S. Tsirkin wrote:
> > But this has nothing to do with Linux.  There is also no guarantee
that
> > the two committees will decide to use exactly the same format. Once
one
> > of them sets the format in stone, we can add support for that format
to
> > linux. If another one is playing nice and uses the same format, we can
> > use the same parsers. If it doesn't linux will have to follow
suit.
> 
> Or Linux decides to support only one of the formats, which would then be
> ACPI.
> 
> Regards,
> 
> 	Joerg
It's really up to hypervisors not guests, linux as a guest can for sure
refuse to work somewhere, but that's normally not very attractive.

-- 
MST