Re: [PATCH v1 3/4] hw/arm/virt-acpi-build: patch guest SRAT for NUMA nodes

[Jason Gunthorpe <jgg@nvidia.com>]

On Mon, Sep 25, 2023 at 03:53:51PM +0100, Jonathan Cameron wrote:
> On Mon, 25 Sep 2023 11:03:28 -0300
> Jason Gunthorpe <jgg@nvidia.com> wrote:
> 
> > On Mon, Sep 25, 2023 at 02:54:40PM +0100, Jonathan Cameron wrote:
> > 
> > > Possible the ASWG folk would say this is fine and I'm reading too much into
> > > the spec, but I'd definitely suggest asking them via the appropriate path,
> > > or throwing in a code first proposal for a comment on this special case and
> > > see what response you get - my guess is it will be 'fix Linux' :(  
> > 
> > The goal here is for qemu to emulate what the bare metal environment
> > is doing.
> > 
> > There may be a legitimate question if what the bare metal FW has done
> > is legitimate (though let's face it, there are lots of creative ACPI
> > things around), but I don't quite see how this is a qemu question?
> > 
> > Unless you are taking the position that qemu should not emulate this
> > HW?
> 
> Ok. I'd failed to register that the bare metal code was doing this though
> with hindsight I guess that is obvious. Though without more info or
> a bare metal example being given its also possible the BIOS was doing
> enumeration etc (like CXL does for all < 2.0 devices) and hence was
> building SRAT with the necessary memory ranges in place - even if the
> driver then does the hot add dance later.

Ankit, maybe you can share some relavent ACPI dumps from the physical
hardware and explain how this compares?

> That's dubious and likely to break at some point unless the spec
> comprehends this use case, but meh, so are lots of other things and
> the hardware vendor gets to pick up the pieces and deal with grumpy
> customers.

Yes.

> I don't currently see this as a safe solution for the proposed other
> use cases however that are virtualization only.

So, how should that translate into a command line experiance? Sounds
like the broad concept is general but this actual specific HW is not?

Thanks,
Jason