[RFC 0/1] drm/mm: Introduce address space shifting

[Lis, Tomasz]

There was no NACK, and no further questions/comments for a month.

 From that, we conclude that the proposed change is considered acceptable.

In case anyone disagrees, please respond now.

We are starting work on a series which will use the proposed drm_mm 
function.

-Tomasz

On 04.02.2025 23:41, Tomasz Lis wrote:
> This RFC asks for introduction of an interface which allows to shift
> a range managed by drm_mm instance without repeating the node list
> creation.
>
> The long explanation:
>
> Single Root I/O Virtualization is becoming a standard GFX feature
> in server environments. Virtual Machines provided with direct access
> to virtualized GFX hardware, in form of VFs, need to support the
> standard set of features expected by Virtual Machine Managers.
> These standard features include ability to save the VM state, and
> later restore the VM, possibly on another machine with different
> setup. For the restore to succeed, the GFX hardware model must match;
> but for its configuration, some differences are often allowed. Such
> alterations may include a different range of non-virtualized
> resources assigned to the VF, including global address spaces.
>
> If any non-virtualized address space is saved, as part of VM state,
> on one machine and restored on another, it may happen that the target
> range differs from source range. To shift the address space,
> currently creating a new drm_mm object is required, and moving all
> nodes to the new object while adding the shift.
>
> GFX hardware handled by Xe driver contains Global Graphics
> Translation Table, which is an example of such non-virtualized
> resource. Should this interface change be accepted, a series which
> utilizes this interface in Xe driver will be prepared.
>
> Signed-off-by: Tomasz Lis <tomasz.lis at intel.com>
>
> Tomasz Lis (1):
>    drm_mm: Introduce address space shifting
>
>   drivers/gpu/drm/drm_mm.c | 24 ++++++++++++++++++++++++
>   include/drm/drm_mm.h     |  1 +
>   2 files changed, 25 insertions(+)
>