On 2024/12/12 15:43, Juergen Gross wrote: > On 07.12.24 11:50, Julia Zhang wrote: >> To implement dGPU prime feature, virtgpu needs to import/export buffer >> between virtio iGPU and passthrough dGPU. Before that, virtgpu should >> check if P2P is possible or not. But calling function >> pci_p2pdma_distance >> in guest VM will only get virtual p2pdma_distance instead of real >> physical >> p2pdma_distance. >> So this series introduce an implementation of virtgpu device_attach >> callback to get p2pdma_distance. And also adds a new virtgpu command to >> pass PCI notations from guest to host and a new xen privcmd to get >> physical >> p2pdma_distance according to the PCI notations in host. > > It is hard to review this series without having a clear picture how > this all is coming together. > > I guess the virtgpu frontend will send a p2pdma_distance request to > the backend, which is running in user mode of dom0. This backend will > then call into the privcmd driver to obtain the needed information and > sends it back to the frontend. > > Can you please confirm my suspicion is correct? Yes, you are right. Julia > > > Juergen
