[PATCH v3 02/13] drm/amdkfd: Use migrate pfns internally

Jordan Niethe
2026-01-23T06:24:02Z

A future change will remove device private pages from the physical
address space. This will mean that device private pages no longer have a
pfn.

A MIGRATE_PFN flag will be introduced that distinguishes between mpfns
that contain a pfn vs an offset into device private memory.

Replace usages of pfns and page_to_pfn() with mpfns and
migrate_pfn_to_page() to prepare for handling this distinction. This
will assist in continuing to use the same code paths for both
MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_COHERENT devices.

Signed-off-by: Jordan Niethe <jniethe@nvidia.com>
---
v2:
- New to series
v3:
- No change
---
drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 15 +++++++--------
drivers/gpu/drm/amd/amdkfd/kfd_migrate.h | 2 +-
2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index 1f03cf7342a5..3dd7a35d19f7 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -210,17 +210,17 @@ svm_migrate_copy_done(struct amdgpu_device *adev, struct dma_fence *mfence)
}

unsigned long
-svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr)
+svm_migrate_addr_to_mpfn(struct amdgpu_device *adev, unsigned long addr)
{
- return (addr + adev->kfd.pgmap.range.start) >> PAGE_SHIFT;
+ return migrate_pfn((addr + adev->kfd.pgmap.range.start) >> PAGE_SHIFT);
}

static void
-svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn)
+svm_migrate_get_vram_page(struct svm_range *prange, unsigned long mpfn)
{
struct page *page;

- page = pfn_to_page(pfn);
+ page = migrate_pfn_to_page(mpfn);
svm_range_bo_ref(prange->svm_bo);
page->zone_device_data = prange->svm_bo;
zone_device_page_init(page, 0);
@@ -231,7 +231,7 @@ svm_migrate_put_vram_page(struct amdgpu_device *adev, unsigned long addr)
{
struct page *page;

- page = pfn_to_page(svm_migrate_addr_to_pfn(adev, addr));
+ page = migrate_pfn_to_page(svm_migrate_addr_to_mpfn(adev, addr));
unlock_page(page);
put_page(page);
}
@@ -241,7 +241,7 @@ svm_migrate_addr(struct amdgpu_device *adev, struct page *page)
{
unsigned long addr;

- addr = page_to_pfn(page) << PAGE_SHIFT;
+ addr = (migrate_pfn_from_page(page) >> MIGRATE_PFN_SHIFT) << PAGE_SHIFT;
return (addr - adev->kfd.pgmap.range.start);
}

@@ -307,9 +307,8 @@ svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange,

if (migrate->src[i] & MIGRATE_PFN_MIGRATE) {
dst[i] = cursor.start + (j << PAGE_SHIFT);
- migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
+ migrate->dst[i] = svm_migrate_addr_to_mpfn(adev, dst[i]);
svm_migrate_get_vram_page(prange, migrate->dst[i]);
- migrate->dst[i] = migrate_pfn(migrate->dst[i]);
mpages++;
}
spage = migrate_pfn_to_page(migrate->src[i]);
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
index 2b7fd442d29c..a80b72abe1e0 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.h
@@ -48,7 +48,7 @@ int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
uint32_t trigger, struct page *fault_page);

unsigned long
-svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr);
+svm_migrate_addr_to_mpfn(struct amdgpu_device *adev, unsigned long addr);

#endif /* IS_ENABLED(CONFIG_HSA_AMD_SVM) */

--
2.34.1