Re: [PATCH v3] drm/amdgpu: Fix incorrect VRAM GART mappings on non-4K page size systems
Applied. Thanks!
Alex
On Wed, May 27, 2026 at 10:34 AM Timur Kristóf wrote:
>
> On 2026. május 27., szerda 15:19:31 közép-európai nyári idő Donet Tom wrote:
> > When mapping VRAM pages into the GART page table,
> > amdgpu_gart_map_vram_range() assumes that the system page size is the
> > same as the GPU page size.
> >
> > On systems with non-4K page sizes, multiple GPU pages can exist within
> > a single CPU page. As a result, the mappings are created incorrectly
> > because fewer page table entries are programmed than required.
> >
> > Fix this by programming the mappings correctly for non-4K page size
> > systems.
> >
> > Fixes: 237d623ae659 ("drm/amdgpu/gart: Add helper to bind VRAM pages (v2)")
> > Reviewed-by: Christian König
> > Signed-off-by: Donet Tom
> > ---
>
> Thank you! The fix looks good to me.
> Reviewed-by: Timur Kristóf
>
>
> > v2 -> v3
> > - Addressed Christian's review comments and added the Reviewed-by tag.
> >
> > v2 -
> > https://lore.kernel.org/all/[email protected]
> > / v1 -
> > https://lore.kernel.org/all/[email protected]
> > / ---
> > ---
> > drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 12
> > 1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c index b6f849d51c2e..c4c21dbbbdbf
> > 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> > @@ -394,7 +394,8 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device
> > *adev, uint64_t pa, uint64_t start_page, uint64_t num_pages,
> > uint64_t flags, void *dst)
> > {
> > - u32 i, idx;
> > + u32 i, j, t, idx;
> > + u64 page_base;
> >
> > /* The SYSTEM flag indicates the pages aren't in VRAM. */
> > WARN_ON_ONCE(flags & AMDGPU_PTE_SYSTEM);
> > @@ -402,9 +403,12 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device
> > *adev, uint64_t pa, if (!drm_dev_enter(adev_to_drm(adev), &idx))
> > return;
> >
> > - for (i = 0; i < num_pages; ++i) {
> > - amdgpu_gmc_set_pte_pde(adev, dst,
> > - start_page + i, pa + AMDGPU_GPU_PAGE_SIZE *
> i, flags);
> > + page_base = pa;
> > + for (i = 0, t = 0; i < num_pages; i++) {
> > + for (j = 0; j < AMDGPU_GPU_PAGES_IN_CPU_PAGE; j++, t++)
> {
> > + amdgpu_gmc_set_pte_pde(adev, dst, start_page
> + t, page_base, flags);
> > + page_base += AMDGPU_GPU_PAGE_SIZE;
> > + }
> > }
> >
> > drm_dev_exit(idx);
>
>
>
>
Re: [PATCH v3] drm/amdgpu: Fix incorrect VRAM GART mappings on non-4K page size systems
On 2026. május 27., szerda 15:19:31 közép-európai nyári idő Donet Tom wrote:
> When mapping VRAM pages into the GART page table,
> amdgpu_gart_map_vram_range() assumes that the system page size is the
> same as the GPU page size.
>
> On systems with non-4K page sizes, multiple GPU pages can exist within
> a single CPU page. As a result, the mappings are created incorrectly
> because fewer page table entries are programmed than required.
>
> Fix this by programming the mappings correctly for non-4K page size
> systems.
>
> Fixes: 237d623ae659 ("drm/amdgpu/gart: Add helper to bind VRAM pages (v2)")
> Reviewed-by: Christian König
> Signed-off-by: Donet Tom
> ---
Thank you! The fix looks good to me.
Reviewed-by: Timur Kristóf
> v2 -> v3
> - Addressed Christian's review comments and added the Reviewed-by tag.
>
> v2 -
> https://lore.kernel.org/all/[email protected]
> / v1 -
> https://lore.kernel.org/all/[email protected]
> / ---
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 12
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c index b6f849d51c2e..c4c21dbbbdbf
> 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
> @@ -394,7 +394,8 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device
> *adev, uint64_t pa, uint64_t start_page, uint64_t num_pages,
> uint64_t flags, void *dst)
> {
> - u32 i, idx;
> + u32 i, j, t, idx;
> + u64 page_base;
>
> /* The SYSTEM flag indicates the pages aren't in VRAM. */
> WARN_ON_ONCE(flags & AMDGPU_PTE_SYSTEM);
> @@ -402,9 +403,12 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device
> *adev, uint64_t pa, if (!drm_dev_enter(adev_to_drm(adev), &idx))
> return;
>
> - for (i = 0; i < num_pages; ++i) {
> - amdgpu_gmc_set_pte_pde(adev, dst,
> - start_page + i, pa + AMDGPU_GPU_PAGE_SIZE *
i, flags);
> + page_base = pa;
> + for (i = 0, t = 0; i < num_pages; i++) {
> + for (j = 0; j < AMDGPU_GPU_PAGES_IN_CPU_PAGE; j++, t++)
{
> + amdgpu_gmc_set_pte_pde(adev, dst, start_page
+ t, page_base, flags);
> + page_base += AMDGPU_GPU_PAGE_SIZE;
> + }
> }
>
> drm_dev_exit(idx);
[PATCH v3] drm/amdgpu: Fix incorrect VRAM GART mappings on non-4K page size systems
When mapping VRAM pages into the GART page table,
amdgpu_gart_map_vram_range() assumes that the system page size is the
same as the GPU page size.
On systems with non-4K page sizes, multiple GPU pages can exist within
a single CPU page. As a result, the mappings are created incorrectly
because fewer page table entries are programmed than required.
Fix this by programming the mappings correctly for non-4K page size
systems.
Fixes: 237d623ae659 ("drm/amdgpu/gart: Add helper to bind VRAM pages (v2)")
Reviewed-by: Christian König
Signed-off-by: Donet Tom
---
v2 -> v3
- Addressed Christian's review comments and added the Reviewed-by tag.
v2 -
https://lore.kernel.org/all/[email protected]/
v1 -
https://lore.kernel.org/all/[email protected]/
---
---
drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c | 12
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
index b6f849d51c2e..c4c21dbbbdbf 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gart.c
@@ -394,7 +394,8 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device *adev,
uint64_t pa,
uint64_t start_page, uint64_t num_pages,
uint64_t flags, void *dst)
{
- u32 i, idx;
+ u32 i, j, t, idx;
+ u64 page_base;
/* The SYSTEM flag indicates the pages aren't in VRAM. */
WARN_ON_ONCE(flags & AMDGPU_PTE_SYSTEM);
@@ -402,9 +403,12 @@ void amdgpu_gart_map_vram_range(struct amdgpu_device
*adev, uint64_t pa,
if (!drm_dev_enter(adev_to_drm(adev), &idx))
return;
- for (i = 0; i < num_pages; ++i) {
- amdgpu_gmc_set_pte_pde(adev, dst,
- start_page + i, pa + AMDGPU_GPU_PAGE_SIZE * i, flags);
+ page_base = pa;
+ for (i = 0, t = 0; i < num_pages; i++) {
+ for (j = 0; j < AMDGPU_GPU_PAGES_IN_CPU_PAGE; j++, t++) {
+ amdgpu_gmc_set_pte_pde(adev, dst, start_page + t,
page_base, flags);
+ page_base += AMDGPU_GPU_PAGE_SIZE;
+ }
}
drm_dev_exit(idx);
--
2.52.0
