Re: [PATCH v2 1/2] vfio: add dma-buf get_tph callback and DMA_BUF_TPH feature

[Zhiping Zhang]

On Tue, May 12, 2026 at 11:31 PM Leon Romanovsky <l...@kernel.org> wrote:
...
> >   #define VFIO_DMA_BUF_TPH_ST (1 << 0)  /* steering_tag valid */
> >   #define VFIO_DMA_BUF_TPH_ST_EXT (1 << 1)  /* steering_tag_ext valid
> > */
> >   struct vfio_device_feature_dma_buf_tph {
> >       __s32 dmabuf_fd;
> >       __u32 flags;
> >       __u16 steering_tag;       /* 8-bit ST */
> >       __u16 steering_tag_ext;   /* 16-bit Extended ST */
>
> I wonder whether `steering_tag` and `steering_tag_ext` can coexist
> and hold different values at the same time.
>
> BTW, please send your patches with diffstat.
>
> Thanks

Yes, firmware can report both `steering_tag` (8-bit ST) and
`steering_tag_ext` (16-bit Extended ST), they may differ. An importer
can consume only the one matching its width. I’ll clarify that in the
next revision.

I’ll also make sure the next posting is sent with diffstat.

Thanks,
Zhiping