[PATCH v2 11/32] drm/xe/svm: Add function to determine if range needs VRAM migration

[Himal Prasad Ghimiray]

xe_svm_range_needs_migrate_to_vram() determines whether range needs
migration to vram or not, for pagefault try at least once.

Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
---
 drivers/gpu/drm/xe/xe_svm.c | 49 +++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/xe/xe_svm.h | 10 ++++++++
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 8cd35553a927..f4ae3feaf9d3 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -709,6 +709,51 @@ int xe_svm_alloc_vram(struct xe_vm *vm, struct xe_tile *tile,
 }
 #endif
 
+static bool supports_4K_migration(struct xe_device *xe)
+{
+	if (xe->info.platform == XE_BATTLEMAGE)
+		return true;
+
+	return false;
+}
+
+/**
+ * xe_svm_range_needs_migrate_to_vram() - SVM range needs migrate to VRAM or not
+ * @range: SVM range for which migration needs to be decided
+ * @vma: vma which has range
+ * @region: default placement for range
+ *
+ * Return: True for range needing migration and migration is supported else false
+ */
+bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vma *vma,
+					u32 region)
+{
+	struct xe_vm *vm = range_to_vm(&range->base);
+	u64 range_size = xe_svm_range_size(range);
+	bool needs_migrate = false;
+
+	if (!range->base.flags.migrate_devmem)
+		return false;
+
+	needs_migrate = region;
+
+	if (needs_migrate && !IS_DGFX(vm->xe)) {
+		drm_warn(&vm->xe->drm, "Platform doesn't support VRAM\n");
+		return false;
+	}
+
+	if (needs_migrate && xe_svm_range_in_vram(range)) {
+		drm_info(&vm->xe->drm, "Range is already in VRAM\n");
+		return false;
+	}
+
+	if (needs_migrate && range_size <= SZ_64K && !supports_4K_migration(vm->xe)) {
+		drm_warn(&vm->xe->drm, "Platform doesn't support SZ_4K range migration\n");
+		return false;
+	}
+
+	return needs_migrate;
+}
 
 /**
  * xe_svm_handle_pagefault() - SVM handle page fault
@@ -763,8 +808,8 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
 	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) {
+	if (!range->skip_migrate &&
+	    xe_svm_range_needs_migrate_to_vram(range, vma, IS_DGFX(vm->xe))) {
 		range->skip_migrate = true;
 
 		err = xe_svm_alloc_vram(vm, tile, range, &ctx);
diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
index 9c4c3aeacc6c..d5be8229ca7e 100644
--- a/drivers/gpu/drm/xe/xe_svm.h
+++ b/drivers/gpu/drm/xe/xe_svm.h
@@ -95,6 +95,9 @@ struct xe_svm_range *xe_svm_range_find_or_insert(struct xe_vm *vm, u64 addr,
 int xe_svm_range_get_pages(struct xe_vm *vm, struct xe_svm_range *range,
 			   struct drm_gpusvm_ctx *ctx);
 
+bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vma *vma,
+					u32 region);
+
 /**
  * xe_svm_range_has_dma_mapping() - SVM range has DMA mapping
  * @range: SVM range
@@ -281,6 +284,13 @@ static inline unsigned long xe_svm_range_size(struct xe_svm_range *range)
 	return 0;
 }
 
+static inline
+bool xe_svm_range_needs_migrate_to_vram(struct xe_svm_range *range, struct xe_vma *vma,
+					u32 region)
+{
+	return false;
+}
+
 #define xe_svm_assert_in_notifier(...) do {} while (0)
 #define xe_svm_range_has_dma_mapping(...) false
 
-- 
2.34.1