Re: [PATCH 9/9] vfio/pci: Add mmap() attributes to DMABUF feature

[Jason Gunthorpe]

On Thu, Apr 16, 2026 at 06:17:52AM -0700, Matt Evans wrote:
> A new field is reserved in vfio_device_feature_dma_buf.flags to
> request CPU-facing memory type attributes for mmap()s of the buffer.
> Add a flag VFIO_DEVICE_FEATURE_DMA_BUF_ATTR_WC, which results in WC
> PTEs for the DMABUF's BAR region.
> 
> Signed-off-by: Matt Evans <mattev@xxxxxxxx>
> ---
>  drivers/vfio/pci/vfio_pci_dmabuf.c | 15 +++++++++++++--
>  drivers/vfio/pci/vfio_pci_priv.h   |  1 +
>  include/uapi/linux/vfio.h          | 12 +++++++++---
>  3 files changed, 23 insertions(+), 5 deletions(-)

Nice and simple

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

> @@ -1549,8 +1551,12 @@ struct vfio_region_dma_range {
>  struct vfio_device_feature_dma_buf {
>  	__u32	region_index;
>  	__u32	open_flags;
> -	__u32   flags;
> -	__u32   nr_ranges;
> +	__u32	flags;
> +	/* Flags sub-field reserved for attribute enum */
> +#define VFIO_DEVICE_FEATURE_DMA_BUF_ATTR_MASK		(0xfU << 28)
> +#define VFIO_DEVICE_FEATURE_DMA_BUF_ATTR_UC		(0 << 28)
> +#define VFIO_DEVICE_FEATURE_DMA_BUF_ATTR_WC		(1 << 28)
> +	__u32	nr_ranges;

Though why did the diff format like this, is there some whitespace
changes? All this did is insert defines it didn't change the members

Jason