Re: [PATCH v3 23/36] drm/xe/vf: Flush and stop CTs in VF post migration recovery

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

On 9/29/2025 4:55 AM, Matthew Brost wrote:
> Flushing CTs (i.e., progressing all pending G2H messages) gives VF
> post-migration recovery an accurate view of which H2G messages the GuC
> has processed, enabling the GuC submission state machine to correctly
> rebuild all state.
> 
> Also, stop all CT traffic, as the CT is not live during VF
> post-migration recovery.
> 
> v3:
>  - xe_guc_ct_flush_and_stop rename (Michal)
>  - Drop extra GuC CT WQ wake up (Michal)
> 
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

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

> ---
>  drivers/gpu/drm/xe/xe_gt_sriov_vf.c |  2 ++
>  drivers/gpu/drm/xe/xe_guc_ct.c      | 10 ++++++++++
>  drivers/gpu/drm/xe/xe_guc_ct.h      |  1 +
>  3 files changed, 13 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index a564f296e4b9..37ef1c42bacb 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_guc_submit.h"
> @@ -1185,6 +1186,7 @@ static void vf_post_migration_shutdown(struct xe_gt *gt)
>  	gt->sriov.vf.migration.recovery_queued = false;
>  	spin_unlock_irq(&gt->sriov.vf.migration.lock);
>  
> +	xe_guc_ct_flush_and_stop(&gt->uc.guc.ct);
>  	xe_guc_submit_pause(&gt->uc.guc);
>  }
>  
> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
> index d84de8544532..fd6e731c0395 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
> @@ -573,6 +573,16 @@ void xe_guc_ct_disable(struct xe_guc_ct *ct)
>  	stop_g2h_handler(ct);
>  }
>  
> +/**
> + * xe_guc_ct_flush_and_stop - Flush and stop all processing of G2H / H2G
> + * @ct: the &xe_guc_ct
> + */
> +void xe_guc_ct_flush_and_stop(struct xe_guc_ct *ct)
> +{
> +	receive_g2h(ct);
> +	xe_guc_ct_stop(ct);
> +}
> +
>  /**
>   * xe_guc_ct_stop - Set GuC to stopped state
>   * @ct: the &xe_guc_ct
> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
> index d6c81325a76c..0a88f4e447fa 100644
> --- a/drivers/gpu/drm/xe/xe_guc_ct.h
> +++ b/drivers/gpu/drm/xe/xe_guc_ct.h
> @@ -17,6 +17,7 @@ int xe_guc_ct_init_post_hwconfig(struct xe_guc_ct *ct);
>  int xe_guc_ct_enable(struct xe_guc_ct *ct);
>  void xe_guc_ct_disable(struct xe_guc_ct *ct);
>  void xe_guc_ct_stop(struct xe_guc_ct *ct);
> +void xe_guc_ct_flush_and_stop(struct xe_guc_ct *ct);
>  void xe_guc_ct_fast_path(struct xe_guc_ct *ct);
>  
>  struct xe_guc_ct_snapshot *xe_guc_ct_snapshot_capture(struct xe_guc_ct *ct);