Re: [PATCH v4 4/4] drm/xe/vf: Do not disable VF migration on ATS-M

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 10/20/2025 10:58 PM, Tomasz Lis wrote:
> The ATS-M does support VF migration, and it has graphics ver below
> the currently allowed range. Experimental support of this platform
> should therefore be available.

maybe the wording here should be:

"Our current support for the VF migration depends on the availability
of the MEMIRQ rather than specific graphics version 20."

"Relax our early migration support checks to allow also use some
older platforms like ATS-M for experiments and testing."

> 
> This change allows experimental VF migration support on ATS-M. It
> is also explicitly not allowing ADL, by adding condition on MEMIRQ.
> Supporting VF migration through MMIO interrupts would require
> some special handling in order to achieve reliability.

hmm, but is this something that we still plan to implement?
all official SR-IOV platforms supported by the Xe driver (PTL+) have MEMIRQ

> 
> v2: Add MEMIRQ condition
> 
> v3: Remove platform version check, as only 12+ are supported by Xe
>  driver anyway (Michal)
> 
> Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_sriov_vf.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
> index 3a3cd9c35aa8..75760da247f4 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
> @@ -159,10 +159,8 @@ static void vf_migration_init_early(struct xe_device *xe)
>  		return xe_sriov_vf_migration_disable(xe,
>  				"experimental feature not available on production builds");
>  
> -	if (GRAPHICS_VER(xe) < 20)
> -		return xe_sriov_vf_migration_disable(xe,
> -				"requires gfx version >= 20, but only %u found",
> -				GRAPHICS_VER(xe));
> +	if (!xe_device_has_memirq(xe))
> +		return xe_sriov_vf_migration_disable(xe, "requires memory-based IRQ support");

but this looks ok, so

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

>  
>  	xe->sriov.vf.migration.enabled = true;
>  }