1 files changed, 110 insertions, 28 deletions

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 24c578e1170e..6345896585de 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -4,6 +4,7 @@
  */
 
 #include "xe_bo.h"
+#include "xe_gt_stats.h"
 #include "xe_gt_tlb_invalidation.h"
 #include "xe_migrate.h"
 #include "xe_module.h"
@@ -15,8 +16,17 @@
 
 static bool xe_svm_range_in_vram(struct xe_svm_range *range)
 {
-	/* Not reliable without notifier lock */
-	return range->base.flags.has_devmem_pages;
+	/*
+	 * Advisory only check whether the range is currently backed by VRAM
+	 * memory.
+	 */
+
+	struct drm_gpusvm_range_flags flags = {
+		/* Pairs with WRITE_ONCE in drm_gpusvm.c */
+		.__flags = READ_ONCE(range->base.flags.__flags),
+	};
+
+	return flags.has_devmem_pages;
 }
 
 static bool xe_svm_range_has_vram_binding(struct xe_svm_range *range)
@@ -339,6 +349,8 @@ static void xe_svm_garbage_collector_work_func(struct work_struct *w)
 	up_write(&vm->lock);
 }
 
+#if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
+
 static struct xe_vram_region *page_to_vr(struct page *page)
 {
 	return container_of(page_pgmap(page), struct xe_vram_region, pagemap);
@@ -577,6 +589,8 @@ static const struct drm_gpusvm_devmem_ops gpusvm_devmem_ops = {
 	.copy_to_ram = xe_svm_copy_to_ram,
 };
 
+#endif
+
 static const struct drm_gpusvm_ops gpusvm_ops = {
 	.range_alloc = xe_svm_range_alloc,
 	.range_free = xe_svm_range_free,
@@ -645,11 +659,19 @@ void xe_svm_fini(struct xe_vm *vm)
 }
 
 static bool xe_svm_range_is_valid(struct xe_svm_range *range,
-				  struct xe_tile *tile)
+				  struct xe_tile *tile,
+				  bool devmem_only)
 {
-	return (range->tile_present & ~range->tile_invalidated) & BIT(tile->id);
+	/*
+	 * Advisory only check whether the range currently has a valid mapping,
+	 * READ_ONCE pairs with WRITE_ONCE in xe_pt.c
+	 */
+	return ((READ_ONCE(range->tile_present) &
+		 ~READ_ONCE(range->tile_invalidated)) & BIT(tile->id)) &&
+		(!devmem_only || xe_svm_range_in_vram(range));
 }
 
+#if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
 static struct xe_vram_region *tile_to_vr(struct xe_tile *tile)
 {
 	return &tile->mem.vram;
@@ -711,12 +733,50 @@ unlock:
 
 	return err;
 }
+#else
+static int xe_svm_alloc_vram(struct xe_vm *vm, struct xe_tile *tile,
+			     struct xe_svm_range *range,
+			     const struct drm_gpusvm_ctx *ctx)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+static bool supports_4K_migration(struct xe_device *xe)
+{
+	if (xe->info.vram_flags & XE_VRAM_FLAGS_NEED64K)
+		return false;
+
+	return true;
+}
+
+static bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range,
+					       struct xe_vma *vma)
+{
+	struct xe_vm *vm = range_to_vm(&range->base);
+	u64 range_size = xe_svm_range_size(range);
+
+	if (!range->base.flags.migrate_devmem)
+		return false;
+
+	if (xe_svm_range_in_vram(range)) {
+		drm_dbg(&vm->xe->drm, "Range is already in VRAM\n");
+		return false;
+	}
+
+	if (range_size <= SZ_64K && !supports_4K_migration(vm->xe)) {
+		drm_dbg(&vm->xe->drm, "Platform doesn't support SZ_4K range migration\n");
+		return false;
+	}
+
+	return true;
+}
 
 /**
  * xe_svm_handle_pagefault() - SVM handle page fault
  * @vm: The VM.
  * @vma: The CPU address mirror VMA.
- * @tile: The tile upon the fault occurred.
+ * @gt: The gt upon the fault occurred.
  * @fault_addr: The GPU fault address.
  * @atomic: The fault atomic access bit.
  *
@@ -726,7 +786,7 @@ unlock:
  * Return: 0 on success, negative error code on error.
  */
 int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
-			    struct xe_tile *tile, u64 fault_addr,
+			    struct xe_gt *gt, u64 fault_addr,
 			    bool atomic)
 {
 	struct drm_gpusvm_ctx ctx = {
@@ -735,17 +795,25 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 			IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR),
 		.check_pages_threshold = IS_DGFX(vm->xe) &&
 			IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR) ? SZ_64K : 0,
+		.devmem_only = atomic && IS_DGFX(vm->xe) &&
+			IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR),
+		.timeslice_ms = atomic && IS_DGFX(vm->xe) &&
+			IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR) ? 5 : 0,
 	};
 	struct xe_svm_range *range;
 	struct drm_gpusvm_range *r;
 	struct drm_exec exec;
 	struct dma_fence *fence;
+	int migrate_try_count = ctx.devmem_only ? 3 : 1;
+	struct xe_tile *tile = gt_to_tile(gt);
 	ktime_t end = 0;
 	int err;
 
 	lockdep_assert_held_write(&vm->lock);
 	xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(vma));
 
+	xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);
+
 retry:
 	/* Always process UNMAPs first so view SVM ranges is current */
 	err = xe_svm_garbage_collector(vm);
@@ -758,24 +826,31 @@ retry:
 	if (IS_ERR(r))
 		return PTR_ERR(r);
 
+	if (ctx.devmem_only && !r->flags.migrate_devmem)
+		return -EACCES;
+
 	range = to_xe_range(r);
-	if (xe_svm_range_is_valid(range, tile))
+	if (xe_svm_range_is_valid(range, tile, ctx.devmem_only))
 		return 0;
 
 	range_debug(range, "PAGE FAULT");
 
-	/* XXX: Add migration policy, for now migrate range once */
-	if (!range->skip_migrate && range->base.flags.migrate_devmem &&
-	    xe_svm_range_size(range) >= SZ_64K) {
-		range->skip_migrate = true;
-
+	if (--migrate_try_count >= 0 &&
+	    xe_svm_range_needs_migrate_to_vram(range, vma)) {
 		err = xe_svm_alloc_vram(vm, tile, range, &ctx);
+		ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
 		if (err) {
-			drm_dbg(&vm->xe->drm,
-				"VRAM allocation failed, falling back to "
-				"retrying fault, asid=%u, errno=%pe\n",
-				vm->usm.asid, ERR_PTR(err));
-			goto retry;
+			if (migrate_try_count || !ctx.devmem_only) {
+				drm_dbg(&vm->xe->drm,
+					"VRAM allocation failed, falling back to retrying fault, asid=%u, errno=%pe\n",
+					vm->usm.asid, ERR_PTR(err));
+				goto retry;
+			} else {
+				drm_err(&vm->xe->drm,
+					"VRAM allocation failed, retry count exceeded, asid=%u, errno=%pe\n",
+					vm->usm.asid, ERR_PTR(err));
+				return err;
+			}
 		}
 	}
 
@@ -783,15 +858,23 @@ retry:
 	err = drm_gpusvm_range_get_pages(&vm->svm.gpusvm, r, &ctx);
 	/* Corner where CPU mappings have changed */
 	if (err == -EOPNOTSUPP || err == -EFAULT || err == -EPERM) {
-		if (err == -EOPNOTSUPP) {
-			range_debug(range, "PAGE FAULT - EVICT PAGES");
-			drm_gpusvm_range_evict(&vm->svm.gpusvm, &range->base);
+		ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
+		if (migrate_try_count > 0 || !ctx.devmem_only) {
+			if (err == -EOPNOTSUPP) {
+				range_debug(range, "PAGE FAULT - EVICT PAGES");
+				drm_gpusvm_range_evict(&vm->svm.gpusvm,
+						       &range->base);
+			}
+			drm_dbg(&vm->xe->drm,
+				"Get pages failed, falling back to retrying, asid=%u, gpusvm=%p, errno=%pe\n",
+				vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
+			range_debug(range, "PAGE FAULT - RETRY PAGES");
+			goto retry;
+		} else {
+			drm_err(&vm->xe->drm,
+				"Get pages failed, retry count exceeded, asid=%u, gpusvm=%p, errno=%pe\n",
+				vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
 		}
-		drm_dbg(&vm->xe->drm,
-			"Get pages failed, falling back to retrying, asid=%u, gpusvm=%p, errno=%pe\n",
-			vm->usm.asid, &vm->svm.gpusvm, ERR_PTR(err));
-		range_debug(range, "PAGE FAULT - RETRY PAGES");
-		goto retry;
 	}
 	if (err) {
 		range_debug(range, "PAGE FAULT - FAIL PAGE COLLECT");
@@ -815,6 +898,7 @@ retry_bind:
 			drm_exec_fini(&exec);
 			err = PTR_ERR(fence);
 			if (err == -EAGAIN) {
+				ctx.timeslice_ms <<= 1;	/* Double timeslice if we have to retry */
 				range_debug(range, "PAGE FAULT - RETRY BIND");
 				goto retry;
 			}
@@ -825,9 +909,6 @@ retry_bind:
 	}
 	drm_exec_fini(&exec);
 
-	if (xe_modparam.always_migrate_to_vram)
-		range->skip_migrate = false;
-
 	dma_fence_wait(fence, false);
 	dma_fence_put(fence);
 
@@ -866,6 +947,7 @@ int xe_svm_bo_evict(struct xe_bo *bo)
 }
 
 #if IS_ENABLED(CONFIG_DRM_XE_DEVMEM_MIRROR)
+
 static struct drm_pagemap_device_addr
 xe_drm_pagemap_device_map(struct drm_pagemap *dpagemap,
 			  struct device *dev,