[PATCH 3/6] drm/ttm: Support partial buffer mappings for ttm_bo_vmap()
Christian König
christian.koenig at amd.com
Fri Jun 14 14:33:03 UTC 2024
Am 14.06.24 um 15:21 schrieb Thomas Zimmermann:
> Add offset and size parameters to ttm_bo_vmap() to allow for partial
> mappings of a buffer object. This brings the functionality on par with
> ttm_bo_kmap().
Well the long term plan was to remove this functionality from
ttm_bo_kmap() and nuke that function sooner or later.
What exactly is the use case for partial mappings?
Regards,
Christian.
>
> Callers pass the byte offset and size within the buffer object and
> receive a page-aligned mapping of the buffer object's memory for the
> specified area.
>
> Also update all callers of ttm_bo_vmap() for the new parameters. As
> before, existing callers map the buffer object's complete memory.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> ---
> drivers/gpu/drm/drm_gem_ttm_helper.c | 2 +-
> drivers/gpu/drm/drm_gem_vram_helper.c | 2 +-
> drivers/gpu/drm/loongson/lsdc_gem.c | 2 +-
> drivers/gpu/drm/qxl/qxl_object.c | 2 +-
> drivers/gpu/drm/ttm/ttm_bo_util.c | 21 +++++++++++++++------
> drivers/gpu/drm/xe/xe_lrc.c | 2 +-
> drivers/gpu/drm/xe/xe_vm.c | 2 +-
> include/drm/ttm/ttm_bo.h | 4 +++-
> 8 files changed, 24 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> index 3734aa2d1c5b5..f26b7c9077a68 100644
> --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> @@ -67,7 +67,7 @@ int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> {
> struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
>
> - return ttm_bo_vmap(bo, map);
> + return ttm_bo_vmap(bo, 0, gem->size, map);
> }
> EXPORT_SYMBOL(drm_gem_ttm_vmap);
>
> diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
> index 6027584406af6..1670f9a459a9d 100644
> --- a/drivers/gpu/drm/drm_gem_vram_helper.c
> +++ b/drivers/gpu/drm/drm_gem_vram_helper.c
> @@ -398,7 +398,7 @@ int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map)
> * no mapping present.
> */
> if (iosys_map_is_null(&gbo->map)) {
> - ret = ttm_bo_vmap(&gbo->bo, &gbo->map);
> + ret = ttm_bo_vmap(&gbo->bo, 0, gbo->bo.base.size, &gbo->map);
> if (ret)
> return ret;
> }
> diff --git a/drivers/gpu/drm/loongson/lsdc_gem.c b/drivers/gpu/drm/loongson/lsdc_gem.c
> index a720d8f532093..f709960c781b9 100644
> --- a/drivers/gpu/drm/loongson/lsdc_gem.c
> +++ b/drivers/gpu/drm/loongson/lsdc_gem.c
> @@ -77,7 +77,7 @@ static int lsdc_gem_object_vmap(struct drm_gem_object *obj, struct iosys_map *ma
> return ret;
> }
>
> - ret = ttm_bo_vmap(tbo, &lbo->map);
> + ret = ttm_bo_vmap(tbo, 0, tbo->base.size, &lbo->map);
> if (ret) {
> drm_err(obj->dev, "ttm bo vmap failed\n");
> lsdc_bo_unpin(lbo);
> diff --git a/drivers/gpu/drm/qxl/qxl_object.c b/drivers/gpu/drm/qxl/qxl_object.c
> index 5893e27a7ae50..9f06d5e26a32c 100644
> --- a/drivers/gpu/drm/qxl/qxl_object.c
> +++ b/drivers/gpu/drm/qxl/qxl_object.c
> @@ -164,7 +164,7 @@ int qxl_bo_vmap_locked(struct qxl_bo *bo, struct iosys_map *map)
> goto out;
> }
>
> - r = ttm_bo_vmap(&bo->tbo, &bo->map);
> + r = ttm_bo_vmap(&bo->tbo, 0, bo->tbo.base.size, &bo->map);
> if (r) {
> qxl_bo_unpin_locked(bo);
> return r;
> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> index a9df0deff2deb..31f9772f05dac 100644
> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> @@ -457,17 +457,23 @@ EXPORT_SYMBOL(ttm_bo_kunmap);
> * ttm_bo_vmap
> *
> * @bo: The buffer object.
> + * @offset: Byte offset into the buffer.
> + * @size: Number of bytes to map.
> * @map: pointer to a struct iosys_map representing the map.
> *
> * Sets up a kernel virtual mapping, using ioremap or vmap to the
> * data in the buffer object. The parameter @map returns the virtual
> * address as struct iosys_map. Unmap the buffer with ttm_bo_vunmap().
> + * The address stored in @map will be aligned to the next lower page
> + * boundaries.
> *
> * Returns
> * -ENOMEM: Out of memory.
> * -EINVAL: Invalid range.
> */
> -int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
> +int ttm_bo_vmap(struct ttm_buffer_object *bo,
> + unsigned long offset, unsigned long size,
> + struct iosys_map *map)
> {
> struct ttm_resource *mem = bo->resource;
> int ret;
> @@ -483,18 +489,18 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
> u16 alloc_flags;
>
> if (mem->bus.addr) {
> - vaddr_iomem = (void __iomem *)mem->bus.addr;
> + vaddr_iomem = (u8 __iomem *)mem->bus.addr + offset;
> alloc_flags = ttm_bo_map_premapped;
> } else if (mem->bus.caching == ttm_write_combined) {
> - vaddr_iomem = ioremap_wc(mem->bus.offset, bo->base.size);
> + vaddr_iomem = ioremap_wc(mem->bus.offset + offset, size);
> alloc_flags = ttm_bo_map_iomap;
> #ifdef CONFIG_X86
> } else if (mem->bus.caching == ttm_cached) {
> - vaddr_iomem = ioremap_cache(mem->bus.offset, bo->base.size);
> + vaddr_iomem = ioremap_cache(mem->bus.offset + offset, size);
> alloc_flags = ttm_bo_map_iomap;
> #endif
> } else {
> - vaddr_iomem = ioremap(mem->bus.offset, bo->base.size);
> + vaddr_iomem = ioremap(mem->bus.offset + offset, size);
> alloc_flags = ttm_bo_map_iomap;
> }
>
> @@ -510,6 +516,9 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
> .no_wait_gpu = false
> };
> struct ttm_tt *ttm = bo->ttm;
> + unsigned long start_page = offset >> PAGE_SHIFT;
> + unsigned long aligned_size = size + (offset - (start_page << PAGE_SHIFT));
> + unsigned long num_pages = DIV_ROUND_UP(aligned_size, PAGE_SIZE);
> pgprot_t prot;
> void *vaddr;
> u16 alloc_flags;
> @@ -523,7 +532,7 @@ int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map)
> * or to make the buffer object look contiguous.
> */
> prot = ttm_io_prot(bo, mem, PAGE_KERNEL);
> - vaddr = vmap(ttm->pages, ttm->num_pages, 0, prot);
> + vaddr = vmap(ttm->pages + start_page, num_pages, 0, prot);
> if (!vaddr)
> return -ENOMEM;
> alloc_flags = ttm_bo_map_vmap;
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index c1bb85d2e243f..3a68fe6d592ed 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1595,7 +1595,7 @@ void xe_lrc_snapshot_capture_delayed(struct xe_lrc_snapshot *snapshot)
> goto put_bo;
>
> xe_bo_lock(bo, false);
> - if (!ttm_bo_vmap(&bo->ttm, &src)) {
> + if (!ttm_bo_vmap(&bo->ttm, 0, bo->ttm.base.size, &src)) {
> xe_map_memcpy_from(xe_bo_device(bo),
> snapshot->lrc_snapshot, &src, snapshot->lrc_offset,
> snapshot->lrc_size);
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index 99bf7412475c0..81306c32f5d09 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -3485,7 +3485,7 @@ void xe_vm_snapshot_capture_delayed(struct xe_vm_snapshot *snap)
>
> if (bo) {
> xe_bo_lock(bo, false);
> - err = ttm_bo_vmap(&bo->ttm, &src);
> + err = ttm_bo_vmap(&bo->ttm, 0, bo->ttm.base.size, &src);
> if (!err) {
> xe_map_memcpy_from(xe_bo_device(bo),
> snap->snap[i].data,
> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
> index 6ccf96c91f3ae..c421ffe3563b1 100644
> --- a/include/drm/ttm/ttm_bo.h
> +++ b/include/drm/ttm/ttm_bo.h
> @@ -375,7 +375,9 @@ int ttm_bo_init_validate(struct ttm_device *bdev, struct ttm_buffer_object *bo,
> int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
> unsigned long num_pages, struct ttm_bo_kmap_obj *map);
> void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> -int ttm_bo_vmap(struct ttm_buffer_object *bo, struct iosys_map *map);
> +int ttm_bo_vmap(struct ttm_buffer_object *bo,
> + unsigned long offset, unsigned long size,
> + struct iosys_map *map);
> void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct iosys_map *map);
> int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo);
> int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
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