Re: [RFC PATCH 10/30] vfio/pci: Export vfio dma-buf specific info for importers

[Jason Gunthorpe]

On Thu, May 29, 2025 at 01:34:53PM +0800, Xu Yilun wrote:
> Export vfio dma-buf specific info by attaching vfio_dma_buf_data in
> struct dma_buf::priv. Provide a helper vfio_dma_buf_get_data() for
> importers to fetch these data. Exporters identify VFIO dma-buf by
> successfully getting these data.
> 
> VFIO dma-buf supports disabling host access to these exported MMIO
> regions when the device is converted to private. Exporters like KVM
> need to identify this type of dma-buf to decide if it is good to use.
> KVM only allows host unaccessible MMIO regions been mapped in private
> roots.
> 
> Export struct kvm * handler attached to the vfio device. This
> allows KVM to do another sanity check. MMIO should only be assigned to
> a CoCo VM if its owner device is already assigned to the same VM.

This doesn't seem right, it should be encapsulated into the standard
DMABUF API in some way.

Jason