Re: [PATCH 0/4] Allow MMIO regions to be exported through dma-buf

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Aug 17, 2022 at 01:11:38PM -0300, Jason Gunthorpe wrote:
> dma-buf has become a way to safely acquire a handle to non-struct page
> memory that can still have lifetime controlled by the exporter. Notably
> RDMA can now import dma-buf FDs and build them into MRs which allows for
> PCI P2P operations. Extend this to allow vfio-pci to export MMIO memory
> from PCI device BARs.
> 
> This series supports a use case for SPDK where a NVMe device will be owned
> by SPDK through VFIO but interacting with a RDMA device. The RDMA device
> may directly access the NVMe CMB or directly manipulate the NVMe device's
> doorbell using PCI P2P.
> 
> However, as a general mechanism, it can support many other scenarios with
> VFIO. I imagine this dmabuf approach to be usable by iommufd as well for
> generic and safe P2P mappings.
> 
> This series goes after the "Break up ioctl dispatch functions to one
> function per ioctl" series.
> 
> This is on github: https://github.com/jgunthorpe/linux/commits/vfio_dma_buf
> 
> Jason Gunthorpe (4):
>   dma-buf: Add dma_buf_try_get()
>   vfio: Add vfio_device_get()
>   vfio_pci: Do not open code pci_try_reset_function()
>   vfio/pci: Allow MMIO regions to be exported through dma-buf
> 
>  drivers/vfio/pci/Makefile           |   1 +
>  drivers/vfio/pci/vfio_pci_config.c  |  22 ++-
>  drivers/vfio/pci/vfio_pci_core.c    |  33 +++-
>  drivers/vfio/pci/vfio_pci_dma_buf.c | 265 ++++++++++++++++++++++++++++

I forget about this..

Alex, do you want to start doing as Linus discused and I will rename
this new file to "dma_buf.c" ?

Or keep this directory as having the vfio_pci_* prefix for
consistency?

Jason