Re: [PATCH] drm/xe/pf: Fix VF FLR synchronization between all GTs

["Piotr Piórkowski" <piotr.piorkowski@intel.com>]

Michal Wajdeczko <michal.wajdeczko@intel.com> wrote on sob [2025-paź-25 14:49:05 +0200]:
> If subsequent VF FLR request is triggered when previous VF FLR
> sequence is still being processed, we ignore it as not needed.
> 
> But in case of the multi-GT platforms, one GT may already finish
> its VF FLR processing and will start a new sequence, which includes
> new cross-GT synchronization point.  However, since other GT may
> be still busy with post-sync cleanup steps, this will put on hold
> this new FLR sequence, which might never finish due to lack of any
> future synchronization checkouts.
> 
> Add additional cross-GT FLR synchronization point when each GT
> ends processing its own FLR sequence.  This should also help to
> cover the case when one GT fails FLR processing before reaching
> the first synchronization point.
> 
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6287
> Fixes: 2a8fcf7cc950 ("drm/xe/pf: Synchronize VF FLR between all GTs")
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> index 2e6bd3d1fe1d..9de05db1f090 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_pf_control.c
> @@ -997,6 +997,8 @@ static void pf_exit_vf_flr_wip(struct xe_gt *gt, unsigned int vfid)
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_GUC_DONE);
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_WAIT_GUC);
>  		pf_escape_vf_state(gt, vfid, XE_GT_SRIOV_STATE_FLR_SEND_START);
> +
> +		xe_sriov_pf_control_sync_flr(gt_to_xe(gt), vfid);
>  	}
>  }

Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>

>  
> -- 
> 2.47.1
> 

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