Re: [PATCH v3 23/23] drm/xe/sriov: Disable SR-IOV if primary GT is disabled via configfs

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

On 10/1/2025 12:56 AM, Matt Roper wrote:
> SR-IOV operation relies on the primary GT's GuC to operate (in both PF
> and VF mode).  If the primary GT is disabled in VF mode, fail the probe.
> If the primary GT is disabled in PF mode, force the device back to
> native (non-sriov) mode.

can we split this into PF and VF specific patch?
> 
> v2:
>  - Move handling to xe_info_init().  (Michal)

oops, I meant _early variant, see below

> 
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_pci.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
> index 4a792e1037d5..44f99c1a39e0 100644
> --- a/drivers/gpu/drm/xe/xe_pci.c
> +++ b/drivers/gpu/drm/xe/xe_pci.c
> @@ -763,6 +763,18 @@ static int xe_info_init(struct xe_device *xe,
>  	int ret;
>  	u8 id;
>  
> +	/* SR-IOV (both PF and VF) relies on the primary GT's GuC */
> +	if ((gt_types_allowed & BIT_ULL(XE_GT_TYPE_MAIN)) == 0) {
> +		if (IS_SRIOV_PF(xe)) {
> +			drm_info(&xe->drm, "Disabling SR-IOV because primary GT is disabled.\n");
> +			pci_sriov_set_totalvfs(pdev, 0);
> +			xe->sriov.__mode = XE_SRIOV_MODE_NONE;

I was thinking about clearing .has_sriov flag somewhere in the
xe_info_init_early() like:

+ 	xe->info.allowed_gt_types = xe_configfs_allowed_gt_types();
+ 	xe->info.has_primary_gt = xe_configfs_primary_gt_supported();
- 	xe->info.has_sriov = desc->has_sriov;
+ 	xe->info.has_sriov = xe->info.has_primary_gt ? desc->has_sriov : 0;

then during SRIOV probe PF will always return as native


alternatively, we can add new condition in xe_sriov_pf_readiness():

+ 	if (!xe_configfs_primary_gt_supported())
+ 		return pf_continue_as_native(xe, "No primary GT");


> +		} else if (IS_SRIOV_VF(xe)) {
> +			drm_err(&xe->drm, "Cannot probe device in SR-IOV VF without primary GT enabled.\n");
> +			return -ENODEV;

and for the VF case, maybe it is sufficient to properly abort
from the read_gmdid(), which now returns an error ?

nit: we can now use: xe_err(xe, "Cannot probe ...");

> +		}
> +	}
> +
>  	/*
>  	 * If this platform supports GMD_ID, we'll detect the proper IP
>  	 * descriptor to use from hardware registers.