Re: [PATCH] virtio-gpu: get p2pdma distance

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Feb 26, 2025 at 02:26:32AM +0000, Zhang, Julia wrote:
> Hi MST,
> 
> On 2025/1/21 22:00, Matias Ezequiel Vara Larsen wrote:
> > On Tue, Jan 14, 2025 at 06:16:13PM +0800, Julia Zhang wrote:
> >> PCI peer-to-peer DMA transaction may be used in guest for some scenes.
> >> For example, dGPU prime feature will let virtio-iGPU access to
> >> passthrough dGPU buffer.
> >>
> >> To support P2P DMA transaction in guest, virtio-gpu needs to check the
> >> compatibility which is represented by p2pdma_distance. This defines a
> >> command VIRTIO_GPU_CMD_P2PDMA_DISTANCE to allow guest send virtual pci
> >> notation of two devices to host and get host physical p2pdma_distance
> >> of these two PCI devices.
> >>
> >> Signed-off-by: Julia Zhang <julia.zhang@amd.com>
> >> ---
> >> Hi all,
> >>
> >> We are trying to implement dGPU prime feature in guest which will let
> >> virtio-iGPU read rendered data of passthrough dGPU. Before that,
> >> virtio gpu driver needs to get p2pdma_distance to check if P2P DMA
> >> transaction is possible or not.
> >>
> >> To implement getting p2pdma_distance, QEMU needs to handle the command
> >> from guest with virtual pci notations of two PCI devices and send it to
> >> host kernel and return host physical distance back to guest.
> >>
> >> So this defines the new command follow the suggestion in
> >> https://lore.kernel.org/all/20241207105537.542441-4-julia.zhang@amd.com/
> >>
> >> Regards,
> >> Julia
> >> ---
> >>   device-types/gpu/description.tex | 29 +++++++++++++++++++++++++++++
> >>   1 file changed, 29 insertions(+)
> >>
> > 
> > Reviewed-by: Matias Ezequiel Vara Larsen <mvaralar@redhat.com>
> > 
> Does this patch meet all requirements for merging? If not, what should I 
> do next step? Should I create a MR on github?
> 
> Regards,
> Julia


No, here are the instructions:
https://github.com/oasis-tcs/virtio-spec/blob/master/README.md#use-of-github-issues