- Fix a panic regression on gen8_ggtt_insert_entries (Matthew Wilcox)

- Fix load issue due to reservation address in ggtt_reserve_guc_top (Javier Pello)
 - Fix a possible deadlock with guc busyness worker (Umesh)
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Merge tag 'drm-intel-fixes-2023-09-28' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

- Fix a panic regression on gen8_ggtt_insert_entries (Matthew Wilcox)
- Fix load issue due to reservation address in ggtt_reserve_guc_top (Javier Pello)
- Fix a possible deadlock with guc busyness worker (Umesh)

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ZRWMI1HmUYPGGylp@intel.com

drivers/gpu/drm/i915/gem/i915_gem_shmem.c

@@ -100,6 +100,7 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st,
 	st->nents = 0;
 	for (i = 0; i < page_count; i++) {
 		struct folio *folio;
+		unsigned long nr_pages;
 		const unsigned int shrink[] = {
 			I915_SHRINK_BOUND | I915_SHRINK_UNBOUND,
 			0,
@@ -150,6 +151,8 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st,
 			}
 		} while (1);
 
+		nr_pages = min_t(unsigned long,
+				folio_nr_pages(folio), page_count - i);
 		if (!i ||
 		    sg->length >= max_segment ||
 		    folio_pfn(folio) != next_pfn) {
@@ -157,13 +160,13 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st,
 				sg = sg_next(sg);
 
 			st->nents++;
-			sg_set_folio(sg, folio, folio_size(folio), 0);
+			sg_set_folio(sg, folio, nr_pages * PAGE_SIZE, 0);
 		} else {
 			/* XXX: could overflow? */
-			sg->length += folio_size(folio);
+			sg->length += nr_pages * PAGE_SIZE;
 		}
-		next_pfn = folio_pfn(folio) + folio_nr_pages(folio);
-		i += folio_nr_pages(folio) - 1;
+		next_pfn = folio_pfn(folio) + nr_pages;
+		i += nr_pages - 1;
 
 		/* Check that the i965g/gm workaround works. */
 		GEM_BUG_ON(gfp & __GFP_DMA32 && next_pfn >= 0x00100000UL);

drivers/gpu/drm/i915/gt/intel_ggtt.c

@@ -511,20 +511,31 @@ void intel_ggtt_unbind_vma(struct i915_address_space *vm,
 	vm->clear_range(vm, vma_res->start, vma_res->vma_size);
 }
 
+/*
+ * Reserve the top of the GuC address space for firmware images. Addresses
+ * beyond GUC_GGTT_TOP in the GuC address space are inaccessible by GuC,
+ * which makes for a suitable range to hold GuC/HuC firmware images if the
+ * size of the GGTT is 4G. However, on a 32-bit platform the size of the GGTT
+ * is limited to 2G, which is less than GUC_GGTT_TOP, but we reserve a chunk
+ * of the same size anyway, which is far more than needed, to keep the logic
+ * in uc_fw_ggtt_offset() simple.
+ */
+#define GUC_TOP_RESERVE_SIZE (SZ_4G - GUC_GGTT_TOP)
+
 static int ggtt_reserve_guc_top(struct i915_ggtt *ggtt)
 {
-	u64 size;
+	u64 offset;
 	int ret;
 
 	if (!intel_uc_uses_guc(&ggtt->vm.gt->uc))
 		return 0;
 
-	GEM_BUG_ON(ggtt->vm.total <= GUC_GGTT_TOP);
-	size = ggtt->vm.total - GUC_GGTT_TOP;
+	GEM_BUG_ON(ggtt->vm.total <= GUC_TOP_RESERVE_SIZE);
+	offset = ggtt->vm.total - GUC_TOP_RESERVE_SIZE;
 
-	ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw, size,
-				   GUC_GGTT_TOP, I915_COLOR_UNEVICTABLE,
-				   PIN_NOEVICT);
+	ret = i915_gem_gtt_reserve(&ggtt->vm, NULL, &ggtt->uc_fw,
+				   GUC_TOP_RESERVE_SIZE, offset,
+				   I915_COLOR_UNEVICTABLE, PIN_NOEVICT);
 	if (ret)
 		drm_dbg(&ggtt->vm.i915->drm,
 			"Failed to reserve top of GGTT for GuC\n");

drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c

@@ -1432,6 +1432,36 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 	unsigned long index;
 	int srcu, ret;
 
+	/*
+	 * Ideally the busyness worker should take a gt pm wakeref because the
+	 * worker only needs to be active while gt is awake. However, the
+	 * gt_park path cancels the worker synchronously and this complicates
+	 * the flow if the worker is also running at the same time. The cancel
+	 * waits for the worker and when the worker releases the wakeref, that
+	 * would call gt_park and would lead to a deadlock.
+	 *
+	 * The resolution is to take the global pm wakeref if runtime pm is
+	 * already active. If not, we don't need to update the busyness stats as
+	 * the stats would already be updated when the gt was parked.
+	 *
+	 * Note:
+	 * - We do not requeue the worker if we cannot take a reference to runtime
+	 *   pm since intel_guc_busyness_unpark would requeue the worker in the
+	 *   resume path.
+	 *
+	 * - If the gt was parked longer than time taken for GT timestamp to roll
+	 *   over, we ignore those rollovers since we don't care about tracking
+	 *   the exact GT time. We only care about roll overs when the gt is
+	 *   active and running workloads.
+	 *
+	 * - There is a window of time between gt_park and runtime suspend,
+	 *   where the worker may run. This is acceptable since the worker will
+	 *   not find any new data to update busyness.
+	 */
+	wakeref = intel_runtime_pm_get_if_active(&gt->i915->runtime_pm);
+	if (!wakeref)
+		return;
+
 	/*
 	 * Synchronize with gt reset to make sure the worker does not
 	 * corrupt the engine/guc stats. NB: can't actually block waiting
@@ -1440,9 +1470,8 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 	 */
 	ret = intel_gt_reset_trylock(gt, &srcu);
 	if (ret)
-		return;
+		goto err_trylock;
 
-	with_intel_runtime_pm(&gt->i915->runtime_pm, wakeref)
 	__update_guc_busyness_stats(guc);
 
 	/* adjust context stats for overflow */
@@ -1452,6 +1481,9 @@ static void guc_timestamp_ping(struct work_struct *wrk)
 	intel_gt_reset_unlock(gt, srcu);
 
 	guc_enable_busyness_worker(guc);
+
+err_trylock:
+	intel_runtime_pm_put(&gt->i915->runtime_pm, wakeref);
 }
 
 static int guc_action_enable_usage_stats(struct intel_guc *guc)