Re: [PATCH v8 2/2] hw/acpi: Implement the SRAT GI affinity structure

[Jonathan Cameron]

On Wed, 6 Mar 2024 12:33:17 +0000
<ankita@nvidia.com> wrote:

> From: Ankit Agrawal <ankita@nvidia.com>
> 
> ACPI spec provides a scheme to associate "Generic Initiators" [1]
> (e.g. heterogeneous processors and accelerators, GPUs, and I/O devices with
> integrated compute or DMA engines GPUs) with Proximity Domains. This is
> achieved using Generic Initiator Affinity Structure in SRAT. During bootup,
> Linux kernel parse the ACPI SRAT to determine the PXM ids and create a NUMA
> node for each unique PXM ID encountered. Qemu currently do not implement
> these structures while building SRAT.
> 
> Add GI structures while building VM ACPI SRAT. The association between
> device and node are stored using acpi-generic-initiator object. Lookup
> presence of all such objects and use them to build these structures.
> 
> The structure needs a PCI device handle [2] that consists of the device BDF.
> The vfio-pci device corresponding to the acpi-generic-initiator object is
> located to determine the BDF.
> 
> [1] ACPI Spec 6.3, Section 5.2.16.6
> [2] ACPI Spec 6.3, Table 5.80
> 
> Cc: Jonathan Cameron <qemu-devel@nongnu.org>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Cc: Cedric Le Goater <clg@redhat.com>
> Signed-off-by: Ankit Agrawal <ankita@nvidia.com>

I guess we gloss over the bisection breakage due to being able to add
these nodes and have them used in HMAT as initiators before we have
added SRAT support.  Linux will moan about it and not use such an HMAT
but meh, it will boot.

You could drag the HMAT change after this but perhaps it's not worth bothering.

Otherwise LGTM
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Could add x86 support (posted in reply to v7 this morning)
and sounds like you have the test nearly ready which is great.

Jonathan