Subject: Re: [PATCH V6 mlx5-next 10/15] vfio: Remove migration protocol v1

From: Cornelia Huck <[email-masked]>
Date: Tue, 01 Feb 2022 12:23:05 +0100

On Sun, Jan 30 2022, Yishai Hadas <[email-masked]> wrote:

> From: Jason Gunthorpe <[email-masked]>
>
> v1 was never implemented and is replaced by v2.
>
> The old uAPI definitions are removed from the header file. As per Linus's
> past remarks we do not have a hard requirement to retain compilation
> compatibility in uapi headers and qemu is already following Linus's
> preferred model of copying the kernel headers.

If we are all in agreement that we will replace v1 with v2 (and I think
we are), we probably should remove the x-enable-migration stuff in QEMU
sooner rather than later, to avoid leaving a trap for the next
unsuspecting person trying to update the headers.

>
> Signed-off-by: Jason Gunthorpe <[email-masked]>
> Signed-off-by: Yishai Hadas <[email-masked]>
> ---
>  include/uapi/linux/vfio.h | 228 --------------------------------------
>  1 file changed, 228 deletions(-)
>
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 9efc35535b29..70c77da5812d 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -323,7 +323,6 @@ struct vfio_region_info_cap_type {
>  #define VFIO_REGION_TYPE_PCI_VENDOR_MASK	(0xffff)
>  #define VFIO_REGION_TYPE_GFX                    (1)
>  #define VFIO_REGION_TYPE_CCW			(2)
> -#define VFIO_REGION_TYPE_MIGRATION              (3)

Do we want to keep region type 3 reserved? Probably not really needed,
but would put us on the safe side.