Re: [PATCH v4 17/34] drm/xe/vf: Don't allow GT reset to be queued during VF post migration recovery

["Lis, Tomasz" <tomasz.lis@intel.com>]

On 10/2/2025 7:53 AM, Matthew Brost wrote:
> With well-behaved software, a GT reset should never occur, nor should it
> happen during VF post-migration recovery. If it does, trigger a warning
> but suppress the GT reset, as VF post-migration recovery is expected to
> bring the VF back to a working state.
>
> v3:
>   - Better commit message (Tomasz)

Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>

-Tomasz

>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_gt.c          |  9 -------
>   drivers/gpu/drm/xe/xe_gt_sriov_vf.c |  7 -----
>   drivers/gpu/drm/xe/xe_guc_submit.c  | 41 +++--------------------------
>   drivers/gpu/drm/xe/xe_guc_submit.h  |  3 ---
>   4 files changed, 4 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
> index 82be38c99205..5f04d562604b 100644
> --- a/drivers/gpu/drm/xe/xe_gt.c
> +++ b/drivers/gpu/drm/xe/xe_gt.c
> @@ -815,11 +815,6 @@ static int do_gt_restart(struct xe_gt *gt)
>   	return 0;
>   }
>   
> -static int gt_wait_reset_unblock(struct xe_gt *gt)
> -{
> -	return xe_guc_wait_reset_unblock(&gt->uc.guc);
> -}
> -
>   static int gt_reset(struct xe_gt *gt)
>   {
>   	unsigned int fw_ref;
> @@ -834,10 +829,6 @@ static int gt_reset(struct xe_gt *gt)
>   
>   	xe_gt_info(gt, "reset started\n");
>   
> -	err = gt_wait_reset_unblock(gt);
> -	if (!err)
> -		xe_gt_warn(gt, "reset block failed to get lifted");
> -
>   	xe_pm_runtime_get(gt_to_xe(gt));
>   
>   	if (xe_fault_inject_gt_reset()) {
> diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> index 85a5678463fa..6ba8b5703ff2 100644
> --- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> +++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
> @@ -1101,17 +1101,11 @@ void xe_gt_sriov_vf_print_version(struct xe_gt *gt, struct drm_printer *p)
>   
>   static void vf_post_migration_shutdown(struct xe_gt *gt)
>   {
> -	int ret = 0;
> -
>   	spin_lock_irq(&gt->sriov.vf.migration.lock);
>   	gt->sriov.vf.migration.recovery_queued = false;
>   	spin_unlock_irq(&gt->sriov.vf.migration.lock);
>   
>   	xe_guc_submit_pause(&gt->uc.guc);
> -	ret |= xe_guc_submit_reset_block(&gt->uc.guc);
> -
> -	if (ret)
> -		xe_gt_sriov_info(gt, "migration recovery encountered ongoing reset\n");
>   }
>   
>   static size_t post_migration_scratch_size(struct xe_device *xe)
> @@ -1145,7 +1139,6 @@ static void vf_post_migration_kickstart(struct xe_gt *gt)
>   	 */
>   	xe_irq_resume(gt_to_xe(gt));
>   
> -	xe_guc_submit_reset_unblock(&gt->uc.guc);
>   	xe_guc_submit_unpause(&gt->uc.guc);
>   }
>   
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index cd5e506527fe..b82976f031e5 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -27,6 +27,7 @@
>   #include "xe_gt.h"
>   #include "xe_gt_clock.h"
>   #include "xe_gt_printk.h"
> +#include "xe_gt_sriov_vf.h"
>   #include "xe_guc.h"
>   #include "xe_guc_capture.h"
>   #include "xe_guc_ct.h"
> @@ -2182,47 +2183,13 @@ static void guc_exec_queue_stop(struct xe_guc *guc, struct xe_exec_queue *q)
>   	}
>   }
>   
> -/**
> - * xe_guc_submit_reset_block - Disallow reset calls on given GuC.
> - * @guc: the &xe_guc struct instance
> - */
> -int xe_guc_submit_reset_block(struct xe_guc *guc)
> -{
> -	return atomic_fetch_or(1, &guc->submission_state.reset_blocked);
> -}
> -
> -/**
> - * xe_guc_submit_reset_unblock - Allow back reset calls on given GuC.
> - * @guc: the &xe_guc struct instance
> - */
> -void xe_guc_submit_reset_unblock(struct xe_guc *guc)
> -{
> -	atomic_set_release(&guc->submission_state.reset_blocked, 0);
> -	wake_up_all(&guc->ct.wq);
> -}
> -
> -static int guc_submit_reset_is_blocked(struct xe_guc *guc)
> -{
> -	return atomic_read_acquire(&guc->submission_state.reset_blocked);
> -}
> -
> -/* Maximum time of blocking reset */
> -#define RESET_BLOCK_PERIOD_MAX (HZ * 5)
> -
> -/**
> - * xe_guc_wait_reset_unblock - Wait until reset blocking flag is lifted, or timeout.
> - * @guc: the &xe_guc struct instance
> - */
> -int xe_guc_wait_reset_unblock(struct xe_guc *guc)
> -{
> -	return wait_event_timeout(guc->ct.wq,
> -				  !guc_submit_reset_is_blocked(guc), RESET_BLOCK_PERIOD_MAX);
> -}
> -
>   int xe_guc_submit_reset_prepare(struct xe_guc *guc)
>   {
>   	int ret;
>   
> +	if (WARN_ON_ONCE(xe_gt_sriov_vf_recovery_inprogress(guc_to_gt(guc))))
> +		return 0;
> +
>   	if (!guc->submission_state.initialized)
>   		return 0;
>   
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.h b/drivers/gpu/drm/xe/xe_guc_submit.h
> index 5b4a0a6fd818..f535fe3895e5 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.h
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.h
> @@ -22,9 +22,6 @@ void xe_guc_submit_stop(struct xe_guc *guc);
>   int xe_guc_submit_start(struct xe_guc *guc);
>   void xe_guc_submit_pause(struct xe_guc *guc);
>   void xe_guc_submit_unpause(struct xe_guc *guc);
> -int xe_guc_submit_reset_block(struct xe_guc *guc);
> -void xe_guc_submit_reset_unblock(struct xe_guc *guc);
> -int xe_guc_wait_reset_unblock(struct xe_guc *guc);
>   void xe_guc_submit_wedge(struct xe_guc *guc);
>   
>   int xe_guc_read_stopped(struct xe_guc *guc);