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

[Xu Yilun]

On Mon, Jun 02, 2025 at 10:30:09AM -0300, Jason Gunthorpe wrote:
> 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.

OK.

> 
> Jason