[PATCH v5 7/8] drm/amdgpu: integrate VRAM migration into SVM fault and prefetch paths

[Junhua Shen <Junhua.Shen@amd.com>]

- Call amdgpu_svm_range_migrate_to_vram() before GPU mapping in
  fault and prefetch paths when VRAM is preferred
- Add device_private_page_owner to drm_gpusvm_ctx for devmem awareness
- Allow AMDGPU_INTERCONNECT_VRAM entries in update_gpu_range proto check
- Skip valid-mapping fast path in prefetch when VRAM migration is
  requested, so prefetch can actively move pages to VRAM

Signed-off-by: Junhua Shen <Junhua.Shen@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_svm_fault.c | 11 ++++++++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c | 20 ++++++++++++++++---
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_fault.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_fault.c
index 3f0c010e4e35..2acfcccd062d 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_fault.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_fault.c
@@ -26,6 +26,8 @@
 #include "amdgpu_svm_attr.h"
 #include "amdgpu_svm_fault.h"
 #include "amdgpu_svm_range.h"
+#include "amdgpu_svm_range_migrate.h"
+#include "amdgpu_migrate.h"
 #include "amdgpu.h"
 #include "amdgpu_vm.h"
 #include "amdgpu_gmc.h"
@@ -160,6 +162,8 @@ static int fault_map_range(struct amdgpu_svm *svm,
 		.check_pages_threshold = devmem_possible ? SZ_64K : 0,
 		.devmem_only = need_vram_migration,
 		.timeslice_ms = need_vram_migration ? 5 : 0,
+		.device_private_page_owner = devmem_possible ?
+			AMDGPU_PGMAP_OWNER(svm->adev) : NULL,
 	};
 	struct amdgpu_svm_range *range;
 	ktime_t timestamp = ktime_get_boottime();
@@ -229,9 +233,12 @@ static int fault_map_range(struct amdgpu_svm *svm,
 	}
 
 	AMDGPU_SVM_RANGE_DEBUG(range, "PAGE FAULT");
-	/* TODO: add migration*/
+	if (need_vram_migration) {
+		AMDGPU_SVM_RANGE_DEBUG(range, "PAGE FAULT - MIGRATE PAGES");
+		amdgpu_svm_range_migrate_to_vram(svm, &range->base);
+	}
 
-	AMDGPU_SVM_RANGE_DEBUG(range, "GET PAGES");
+	AMDGPU_SVM_RANGE_DEBUG(range, "PAGE FAULT - GET PAGES");
 	ret = amdgpu_svm_range_get_pages(svm, &range->base, &map_ctx);
 	if (ret == -EOPNOTSUPP || ret == -EFAULT) {
 		/*
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
index 21a2b0c49c53..88923e6a0194 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_svm_range.c
@@ -26,6 +26,7 @@
 #include "amdgpu_svm_attr.h"
 #include "amdgpu_svm_range.h"
 #include "amdgpu_svm_fault.h"
+#include "amdgpu_svm_range_migrate.h"
 #include "amdgpu_migrate.h"
 #include "amdgpu.h"
 #include "amdgpu_vm.h"
@@ -279,7 +280,8 @@ amdgpu_svm_range_update_gpu_range(struct amdgpu_svm *svm,
 		unsigned long start_page, last_page;
 		bool is_last_seg;
 
-		if (entry->proto != DRM_INTERCONNECT_SYSTEM)
+		if (entry->proto != DRM_INTERCONNECT_SYSTEM &&
+		    entry->proto != AMDGPU_INTERCONNECT_VRAM)
 			return -EOPNOTSUPP;
 
 		pte_flags = amdgpu_svm_range_attr_pte_flags(svm, attrs,
@@ -431,6 +433,8 @@ amdgpu_svm_range_map_attrs(struct amdgpu_svm *svm,
 		.devmem_possible = devmem_possible,
 		.devmem_only = need_vram_migration,
 		.check_pages_threshold = devmem_possible ? SZ_64K : 0,
+		.device_private_page_owner = devmem_possible ?
+			AMDGPU_PGMAP_OWNER(svm->adev) : NULL,
 	};
 
 	while (addr < end) {
@@ -453,12 +457,22 @@ amdgpu_svm_range_map_attrs(struct amdgpu_svm *svm,
 		if (next_addr <= addr)
 			return -EINVAL;
 
-		if (amdgpu_svm_range_is_valid(svm, range, attrs)) {
+		/*
+		 * Prefetch to device memory should still run migration logic even if
+		 * the current GPU mapping is already valid. This allows prefetch
+		 * requests to actively move backing pages to VRAM instead of being
+		 * skipped by the valid-mapping fast path.
+		 */
+		if (amdgpu_svm_range_is_valid(svm, range, attrs) &&
+		    !need_vram_migration) {
 			addr = next_addr;
 			continue;
 		}
 
-		/* TODO: add migration */
+		if (need_vram_migration) {
+			AMDGPU_SVM_RANGE_DEBUG(range, "PREFETCH - MIGRATE PAGES");
+			amdgpu_svm_range_migrate_to_vram(svm, &range->base);
+		}
 
 		AMDGPU_SVM_RANGE_DEBUG(range, "GET PAGES");
 
-- 
2.34.1