Re: [PATCH v1 2/7] drm/xe/vf: Finish RESFIX by reset if CTB not enabled

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

On 14.05.2025 00:49, Tomasz Lis wrote:
> The RESFIX state should be achievable only when CTB communication is
> enabled. If CTB was disabled and we still got it, then either we're
> dealing with unclean initial state, or the driver is not currently
> functional. In these cases, exit the RESFIX state by reset.
> 
> Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.c | 10 ++++++++++
>  drivers/gpu/drm/xe/xe_sriov_vf.c    | 18 ++++++++++++++++++
>  drivers/gpu/drm/xe/xe_sriov_vf.h    |  1 +
>  3 files changed, 29 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index 4ff7ae1a5f16..b9af112ca771 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> @@ -23,6 +23,7 @@
>  #include "xe_gt_sriov_vf.h"
>  #include "xe_gt_sriov_vf_types.h"
>  #include "xe_guc.h"
> +#include "xe_guc_ct.h"
>  #include "xe_guc_hxg_helpers.h"
>  #include "xe_guc_relay.h"
>  #include "xe_mmio.h"
> @@ -932,6 +933,15 @@ void xe_gt_sriov_vf_migrated_event_handler(struct xe_gt *gt)
>  
>  	xe_gt_assert(gt, IS_SRIOV_VF(xe));
>  
> +	if (!xe_guc_ct_enabled(&gt->uc.guc.ct)) {
> +		/*
> +		 * If at driver init, ignore migration which happened
> +		 * before the driver was loaded.
> +		 */
> +		xe_sriov_vf_post_migration_reset_guc_state(xe);

this triggers async-reset on all GTs, not only on this one where CTB is
off but on other GTs that might have CTB enabled and running - is it
safe to reset them too?

and if CTB is off, can't we just wait with "recovery" once we actually
start the CTB later on?

> +		return;
> +	}
> +
>  	set_bit(gt->info.id, &xe->sriov.vf.migration.gt_flags);
>  	/*
>  	 * We need to be certain that if all flags were set, at least one
> diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
> index 2674fa948fda..940b81036321 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
> @@ -134,6 +134,24 @@ void xe_sriov_vf_init_early(struct xe_device *xe)
>  	INIT_WORK(&xe->sriov.vf.migration.worker, migration_worker_func);
>  }
>  
> +/**
> + * xe_sriov_vf_post_migration_reset_guc_state - Reset VF state in all GuCs.
> + * @xe: the &xe_device struct instance
> + *
> + * This function sends VF state reset to GuC, as a way of exiting RESFIX
> + * state if a proper post-migration recovery procedure has failed.
> + */
> +void xe_sriov_vf_post_migration_reset_guc_state(struct xe_device *xe)
> +{
> +	struct xe_gt *gt;
> +	unsigned int id;
> +
> +	for_each_gt(gt, xe, id)
> +		xe_gt_reset_async(gt);
> +
> +	drm_notice(&xe->drm, "VF migration recovery reset scheduled\n");

note that there likely will be already

GT0: trying reset from xe_sriov_vf_post_migration_reset_guc_state
GT0: reset queued
GT1: trying reset from xe_sriov_vf_post_migration_reset_guc_state
GT1: reset queued

> +}
> +
>  /**
>   * vf_post_migration_requery_guc - Re-query GuC for current VF provisioning.
>   * @xe: the &xe_device struct instance
> diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.h b/drivers/gpu/drm/xe/xe_sriov_vf.h
> index 7b8622cff2b7..ba846af34a13 100644
> --- a/drivers/gpu/drm/xe/xe_sriov_vf.h
> +++ b/drivers/gpu/drm/xe/xe_sriov_vf.h
> @@ -10,5 +10,6 @@ struct xe_device;
>  
>  void xe_sriov_vf_init_early(struct xe_device *xe);
>  void xe_sriov_vf_start_migration_recovery(struct xe_device *xe);
> +void xe_sriov_vf_post_migration_reset_guc_state(struct xe_device *xe);
>  
>  #endif