Re: [RFC PATCH 5/6] Add gnttab IOCTLs that allow sharing already existing memory

["Durrant, Paul" <xadimgnik@xxxxxxxxx>]

On 12/12/2023 09:38, Rafał Wojdyła wrote:
> IOCTL_XENIFACE_GNTTAB_PERMIT_FOREIGN_ACCESS shares pages that are
> newly allocated by the driver. This commit adds new IOCTLs:
> IOCTL_XENIFACE_GNTTAB_PERMIT_FOREIGN_ACCESS_V2,
> IOCTL_XENIFACE_GNTTAB_REVOKE_FOREIGN_ACCESS_V2,
> IOCTL_XENIFACE_GNTTAB_MAP_FOREIGN_PAGES_V2
> and IOCTL_XENIFACE_GNTTAB_UNMAP_FOREIGN_PAGES_V2.
>
> IOCTL_XENIFACE_GNTTAB_PERMIT_FOREIGN_ACCESS_V2 allows specifying
> user-mode address of a memory region that will be shared
> (the region is locked for the duration).
>
> All _V2 IOCTLs use user-mode address of the shared region
> as a unique (per-process) request identifier. This differs from
> the existing IOCTLs that use client-supplied RequestId. _V2 IOCTLs
> should be considered as preferable since they don't require
> the client to manage IDs.
>
> Signed-off-by: Rafał Wojdyła <omeg@xxxxxxxxxxxxxxxxxxxxxx>
> ---
>   include/xeniface_ioctls.h   |  94 ++++-
>   src/xeniface/ioctl_gnttab.c | 711 ++++++++++++++++++++++--------------
>   src/xeniface/ioctls.c       |  25 +-
>   src/xeniface/ioctls.h       |  75 ++--
>   src/xeniface/irp_queue.c    |  27 +-
>   src/xeniface/irp_queue.h    |   2 +-
>   6 files changed, 596 insertions(+), 338 deletions(-)
Acked-by: Paul Durrant <paul@xxxxxxx>