Re: [RFC v1 0/4] Expose GPU memory as coherently CPU accessible

["Cédric Le Goater" <clegoate@redhat.com>]

Hello Ankit,

On 6/6/23 01:50, ankita@nvidia.com wrote:
> From: Ankit Agrawal <ankita@nvidia.com>
> 
> NVIDIA is building systems which allows the CPU to coherently access
> GPU memory. This GPU device memory can be added and managed by the
> kernel memory manager. The patch holds the required changes in QEMU
> to expose this memory to the device assigned VMs.
> 
> The GPU device memory region is exposed as device BAR1 and QEMU mmaps to
> it. It then adds new proximity domains to represent the memory in the
> VM ACPI SRAT. This allows the device memory to be added as separate NUMA
> nodes inside the VM. The proximity domains (PXM) are passed to the VM
> using ACPI DSD properties to help VM kernel modules add the memory.
> 
> Current Linux cannot create NUMA nodes on the fly, hence creating enough
> NUMA nodes in ACPI is needed so that they are available at the VM bootup
> time. The physical platform firwmare provides 8 NUMA nodes, which QEMU
> is emulating here.
> 
> A new vfio-pci variant driver is added to manage the device memory and
> report as a BAR. Ongoing review of the corresponding kernel side changes
> along with the new vfio-pci variant driver.
> Ref: https://lore.kernel.org/lkml/20230405180134.16932-1-ankita@nvidia.com/
> 
> Applied over v8.0.2.
> 
> Ankit Agrawal (4):
>    qemu: add GPU memory information as object
>    qemu: patch guest SRAT for GPU memory
>    qemu: patch guest DSDT for GPU memory
>    qemu: adjust queried bar size to power-of-2


Please use "vfio:" subject prefix when modifying the hw/vfio files.
If you are not sure and want to know what is the current practice,
simply run :
    
   git log --pretty=oneline  <files>

Also, to know who to send the series, please use :

   ./scripts/get_maintainer.pl <patches>

Thanks,

C.

> 
>   hw/arm/virt-acpi-build.c    | 54 ++++++++++++++++++++++++++++
>   hw/pci-host/gpex-acpi.c     | 71 ++++++++++++++++++++++++++++++++++++
>   hw/vfio/common.c            |  2 +-
>   hw/vfio/pci-quirks.c        | 13 +++++++
>   hw/vfio/pci.c               | 72 +++++++++++++++++++++++++++++++++++++
>   hw/vfio/pci.h               |  1 +
>   include/hw/pci/pci_device.h |  3 ++
>   7 files changed, 215 insertions(+), 1 deletion(-)
>