[PATCH v3 15/36] drm/xe/vf: Remove memory allocations from VF post migration recovery

[Matthew Brost <matthew.brost@intel.com>]

VF post migration recovery is the path of dma-fence signaling / reclaim,
avoid memory allocations in this path.

v3:
 - s/lrc_wa_bb/scratch (Tomasz)

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_gt_sriov_vf.c       | 23 +++++++++++++----------
 drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h |  2 ++
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
index ae9df9c0876d..6f15619efe01 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
@@ -1214,17 +1214,13 @@ static size_t post_migration_scratch_size(struct xe_device *xe)
 
 static int vf_post_migration_fixups(struct xe_gt *gt)
 {
+	void *buf = gt->sriov.vf.migration.scratch;
 	s64 shift;
-	void *buf;
 	int err;
 
-	buf = kmalloc(post_migration_scratch_size(gt_to_xe(gt)), GFP_ATOMIC);
-	if (!buf)
-		return -ENOMEM;
-
 	err = xe_gt_sriov_vf_query_config(gt);
 	if (err)
-		goto out;
+		return err;
 
 	shift = xe_gt_sriov_vf_ggtt_shift(gt);
 	if (shift) {
@@ -1232,12 +1228,10 @@ static int vf_post_migration_fixups(struct xe_gt *gt)
 		xe_gt_sriov_vf_default_lrcs_hwsp_rebase(gt);
 		err = xe_guc_contexts_hwsp_rebase(&gt->uc.guc, buf);
 		if (err)
-			goto out;
+			return err;
 	}
 
-out:
-	kfree(buf);
-	return err;
+	return 0;
 }
 
 static void vf_post_migration_kickstart(struct xe_gt *gt)
@@ -1322,9 +1316,18 @@ static void migration_worker_func(struct work_struct *w)
  */
 int xe_gt_sriov_vf_init_early(struct xe_gt *gt)
 {
+	void *buf;
+
 	if (!xe_sriov_vf_migration_supported(gt_to_xe(gt)))
 		return 0;
 
+	buf = drmm_kmalloc(&gt_to_xe(gt)->drm,
+			   post_migration_scratch_size(gt_to_xe(gt)),
+			   GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	gt->sriov.vf.migration.scratch = buf;
 	init_rwsem(&gt->sriov.vf.self_config.lock);
 	spin_lock_init(&gt->sriov.vf.migration.lock);
 	INIT_WORK(&gt->sriov.vf.migration.worker, migration_worker_func);
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
index 53680a2f188a..a63b6004b0b7 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
@@ -58,6 +58,8 @@ struct xe_gt_sriov_vf_migration {
 	struct work_struct worker;
 	/** @lock: Protects recovery_queued */
 	spinlock_t lock;
+	/** @scratch: Scratch memory for VF recovery */
+	void *scratch;
 	/** @recovery_queued: VF post migration recovery in queued */
 	bool recovery_queued;
 	/** @recovery_inprogress: VF post migration recovery in progress */
-- 
2.34.1