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