[PATCH v6 2/8] drm/ttm: Add ttm_bo_access
Christian König
ckoenig.leichtzumerken at gmail.com
Mon Nov 4 19:28:34 UTC 2024
Am 04.11.24 um 18:34 schrieb Rodrigo Vivi:
> On Thu, Oct 31, 2024 at 04:43:19PM -0700, Matthew Brost wrote:
>> On Thu, Oct 31, 2024 at 11:10:42AM -0700, Matthew Brost wrote:
>>> Non-contiguous VRAM cannot easily be mapped in TTM nor can non-visible
>>> VRAM easily be accessed. Add ttm_bo_access, which is similar to
>>> ttm_bo_vm_access, to access such memory.
>>>
>>> v4:
>>> - Fix checkpatch warnings (CI)
>>> v5:
>>> - Fix checkpatch warnings (CI)
>>> v6:
>>> - Fix kernel doc (Auld)
>>>
>> Christian - Do you mind if I merge patch along with the rest of the
>> series to drm-xe-next?
> Ray, Christian,
>
> ack on getting this patch to drm-xe-next?
No, we actually spend quite some time removing the single page mapping
functionality for BOs.
You need a really good justification to bring that back.
Regards,
Christian.
>
>> Matt
>>
>>> Reported-by: Christoph Manszewski <christoph.manszewski at intel.com>
>>> Suggested-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>
>>> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>>> Tested-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>>> Reviewed-by: Matthew Auld <matthew.auld at intel.com>
>>> ---
>>> drivers/gpu/drm/ttm/ttm_bo_util.c | 86 +++++++++++++++++++++++++++++++
>>> drivers/gpu/drm/ttm/ttm_bo_vm.c | 65 +----------------------
>>> include/drm/ttm/ttm_bo.h | 2 +
>>> 3 files changed, 89 insertions(+), 64 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> index d939925efa81..77e760ea7193 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> @@ -919,3 +919,89 @@ s64 ttm_lru_walk_for_evict(struct ttm_lru_walk *walk, struct ttm_device *bdev,
>>>
>>> return progress;
>>> }
>>> +
>>> +static int ttm_bo_access_kmap(struct ttm_buffer_object *bo,
>>> + unsigned long offset,
>>> + void *buf, int len, int write)
>>> +{
>>> + unsigned long page = offset >> PAGE_SHIFT;
>>> + unsigned long bytes_left = len;
>>> + int ret;
>>> +
>>> + /* Copy a page at a time, that way no extra virtual address
>>> + * mapping is needed
>>> + */
>>> + offset -= page << PAGE_SHIFT;
>>> + do {
>>> + unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
>>> + struct ttm_bo_kmap_obj map;
>>> + void *ptr;
>>> + bool is_iomem;
>>> +
>>> + ret = ttm_bo_kmap(bo, page, 1, &map);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + ptr = (void *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
>>> + WARN_ON_ONCE(is_iomem);
>>> + if (write)
>>> + memcpy(ptr, buf, bytes);
>>> + else
>>> + memcpy(buf, ptr, bytes);
>>> + ttm_bo_kunmap(&map);
>>> +
>>> + page++;
>>> + buf += bytes;
>>> + bytes_left -= bytes;
>>> + offset = 0;
>>> + } while (bytes_left);
>>> +
>>> + return len;
>>> +}
>>> +
>>> +/**
>>> + * ttm_bo_access - Helper to access a buffer object
>>> + *
>>> + * @bo: ttm buffer object
>>> + * @offset: access offset into buffer object
>>> + * @buf: pointer to caller memory to read into or write from
>>> + * @len: length of access
>>> + * @write: write access
>>> + *
>>> + * Utility function to access a buffer object. Useful when buffer object cannot
>>> + * be easily mapped (non-contiguous, non-visible, etc...).
>>> + *
>>> + * Returns:
>>> + * @len if successful, negative error code on failure.
>>> + */
>>> +int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
>>> + void *buf, int len, int write)
>>> +{
>>> + int ret;
>>> +
>>> + if (len < 1 || (offset + len) > bo->base.size)
>>> + return -EIO;
>>> +
>>> + ret = ttm_bo_reserve(bo, true, false, NULL);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + switch (bo->resource->mem_type) {
>>> + case TTM_PL_SYSTEM:
>>> + fallthrough;
>>> + case TTM_PL_TT:
>>> + ret = ttm_bo_access_kmap(bo, offset, buf, len, write);
>>> + break;
>>> + default:
>>> + if (bo->bdev->funcs->access_memory)
>>> + ret = bo->bdev->funcs->access_memory
>>> + (bo, offset, buf, len, write);
>>> + else
>>> + ret = -EIO;
>>> + }
>>> +
>>> + ttm_bo_unreserve(bo);
>>> +
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL(ttm_bo_access);
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> index 2c699ed1963a..20b1e5f78684 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
>>> @@ -366,45 +366,6 @@ void ttm_bo_vm_close(struct vm_area_struct *vma)
>>> }
>>> EXPORT_SYMBOL(ttm_bo_vm_close);
>>>
>>> -static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo,
>>> - unsigned long offset,
>>> - uint8_t *buf, int len, int write)
>>> -{
>>> - unsigned long page = offset >> PAGE_SHIFT;
>>> - unsigned long bytes_left = len;
>>> - int ret;
>>> -
>>> - /* Copy a page at a time, that way no extra virtual address
>>> - * mapping is needed
>>> - */
>>> - offset -= page << PAGE_SHIFT;
>>> - do {
>>> - unsigned long bytes = min(bytes_left, PAGE_SIZE - offset);
>>> - struct ttm_bo_kmap_obj map;
>>> - void *ptr;
>>> - bool is_iomem;
>>> -
>>> - ret = ttm_bo_kmap(bo, page, 1, &map);
>>> - if (ret)
>>> - return ret;
>>> -
>>> - ptr = (uint8_t *)ttm_kmap_obj_virtual(&map, &is_iomem) + offset;
>>> - WARN_ON_ONCE(is_iomem);
>>> - if (write)
>>> - memcpy(ptr, buf, bytes);
>>> - else
>>> - memcpy(buf, ptr, bytes);
>>> - ttm_bo_kunmap(&map);
>>> -
>>> - page++;
>>> - buf += bytes;
>>> - bytes_left -= bytes;
>>> - offset = 0;
>>> - } while (bytes_left);
>>> -
>>> - return len;
>>> -}
>>> -
>>> int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>> void *buf, int len, int write)
>>> {
>>> @@ -412,32 +373,8 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
>>> unsigned long offset = (addr) - vma->vm_start +
>>> ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
>>> << PAGE_SHIFT);
>>> - int ret;
>>> -
>>> - if (len < 1 || (offset + len) > bo->base.size)
>>> - return -EIO;
>>>
>>> - ret = ttm_bo_reserve(bo, true, false, NULL);
>>> - if (ret)
>>> - return ret;
>>> -
>>> - switch (bo->resource->mem_type) {
>>> - case TTM_PL_SYSTEM:
>>> - fallthrough;
>>> - case TTM_PL_TT:
>>> - ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
>>> - break;
>>> - default:
>>> - if (bo->bdev->funcs->access_memory)
>>> - ret = bo->bdev->funcs->access_memory(
>>> - bo, offset, buf, len, write);
>>> - else
>>> - ret = -EIO;
>>> - }
>>> -
>>> - ttm_bo_unreserve(bo);
>>> -
>>> - return ret;
>>> + return ttm_bo_access(bo, offset, buf, len, write);
>>> }
>>> EXPORT_SYMBOL(ttm_bo_vm_access);
>>>
>>> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h
>>> index 5804408815be..8ea11cd8df39 100644
>>> --- a/include/drm/ttm/ttm_bo.h
>>> +++ b/include/drm/ttm/ttm_bo.h
>>> @@ -421,6 +421,8 @@ void ttm_bo_unpin(struct ttm_buffer_object *bo);
>>> int ttm_bo_evict_first(struct ttm_device *bdev,
>>> struct ttm_resource_manager *man,
>>> struct ttm_operation_ctx *ctx);
>>> +int ttm_bo_access(struct ttm_buffer_object *bo, unsigned long offset,
>>> + void *buf, int len, int write);
>>> vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
>>> struct vm_fault *vmf);
>>> vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
>>> --
>>> 2.34.1
>>>
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