Thread (22 messages) 22 messages, 7 authors, 2021-10-13
STALE1711d REVIEWED: 1 (1M)

[PATCH v1 06/12] drm/amdkfd: add SPM support for SVM

From: Alex Sierra <hidden>
Date: 2021-10-12 17:13:15
Also in: amd-gfx, dri-devel, linux-ext4, linux-xfs
Subsystem: amd kfd, drm drivers, radeon and amdgpu drm drivers, the rest · Maintainers: Felix Kuehling, David Airlie, Simona Vetter, Alex Deucher, Christian König, Linus Torvalds

When CPU is connected throug XGMI, it has coherent
access to VRAM resource. In this case that resource
is taken from a table in the device gmc aperture base.
This resource is used along with the device type, which could
be DEVICE_PRIVATE or DEVICE_COHERENT to create the device
page map region.

Signed-off-by: Alex Sierra <redacted>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
v7:
Remove lookup_resource call, so export symbol for this function
is not longer required. Patch dropped "kernel: resource:
lookup_resource as exported symbol"
---
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 32 +++++++++++++++---------
 1 file changed, 20 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index ffad39ffa8c6..9efc97d55077 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -866,7 +866,7 @@ int svm_migrate_init(struct amdgpu_device *adev)
 {
 	struct kfd_dev *kfddev = adev->kfd.dev;
 	struct dev_pagemap *pgmap;
-	struct resource *res;
+	struct resource *res = NULL;
 	unsigned long size;
 	void *r;
 
@@ -881,22 +881,29 @@ int svm_migrate_init(struct amdgpu_device *adev)
 	 * should remove reserved size
 	 */
 	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
-	res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
-	if (IS_ERR(res))
-		return -ENOMEM;
+	if (adev->gmc.xgmi.connected_to_cpu) {
+		pgmap->range.start = adev->gmc.aper_base;
+		pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 1;
+		pgmap->type = MEMORY_DEVICE_COHERENT;
+	} else {
+		res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+		if (IS_ERR(res))
+			return -ENOMEM;
+		pgmap->range.start = res->start;
+		pgmap->range.end = res->end;
+		pgmap->type = MEMORY_DEVICE_PRIVATE;
+	}
 
-	pgmap->type = MEMORY_DEVICE_PRIVATE;
 	pgmap->nr_range = 1;
-	pgmap->range.start = res->start;
-	pgmap->range.end = res->end;
 	pgmap->ops = &svm_migrate_pgmap_ops;
 	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
-	pgmap->flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+	pgmap->flags = 0;
 	r = devm_memremap_pages(adev->dev, pgmap);
 	if (IS_ERR(r)) {
 		pr_err("failed to register HMM device memory\n");
-		devm_release_mem_region(adev->dev, res->start,
-					res->end - res->start + 1);
+		if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+			devm_release_mem_region(adev->dev, res->start,
+						res->end - res->start + 1);
 		return PTR_ERR(r);
 	}
 
@@ -915,6 +922,7 @@ void svm_migrate_fini(struct amdgpu_device *adev)
 	struct dev_pagemap *pgmap = &adev->kfd.dev->pgmap;
 
 	devm_memunmap_pages(adev->dev, pgmap);
-	devm_release_mem_region(adev->dev, pgmap->range.start,
-				pgmap->range.end - pgmap->range.start + 1);
+	if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+		devm_release_mem_region(adev->dev, pgmap->range.start,
+					pgmap->range.end - pgmap->range.start + 1);
 }
-- 
2.32.0

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