[PATCH v2 1/1] drm/amdgpu: Add gem_prime_mmap support
Samuel Li
samuel.li at amd.com
Tue Sep 19 21:22:02 UTC 2017
>> + vma->vm_pgoff = amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;
> Maybe better use "vma->vm_pgoff += amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;", but I'm not sure.
> How other drivers handle this?
This is a good catch. Looks like pgoff is honored during prime mmap, not a fake offset here.
>> + dma_buf->ops = &amdgpu_dmabuf_ops;
> This isn't race free and needs to be fixed.
> Better add callbacks to drm_prime.c similar to drm_gem_dmabuf_mmap().
What do you mean "This isn't race free"?
Regards,
Sam
On 2017-09-15 11:05 AM, Christian König wrote:
> Am 14.09.2017 um 00:39 schrieb Samuel Li:
>> v2: drop hdp invalidate/flush.
>>
>> Signed-off-by: Samuel Li <Samuel.Li at amd.com>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 ++
>> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 3 +-
>> drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c | 77 ++++++++++++++++++++++++++++++-
>> 3 files changed, 81 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index d2aaad7..188b705 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -395,11 +395,14 @@ amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
>> struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>> struct drm_gem_object *gobj,
>> int flags);
>> +struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
>> + struct dma_buf *dma_buf);
>> int amdgpu_gem_prime_pin(struct drm_gem_object *obj);
>> void amdgpu_gem_prime_unpin(struct drm_gem_object *obj);
>> struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *);
>> void *amdgpu_gem_prime_vmap(struct drm_gem_object *obj);
>> void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr);
>> +int amdgpu_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
>> int amdgpu_gem_debugfs_init(struct amdgpu_device *adev);
>> /* sub-allocation manager, it has to be protected by another lock.
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> index 2cdf844..9b63ac5 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
>> @@ -835,7 +835,7 @@ static struct drm_driver kms_driver = {
>> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
>> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
>> .gem_prime_export = amdgpu_gem_prime_export,
>> - .gem_prime_import = drm_gem_prime_import,
>> + .gem_prime_import = amdgpu_gem_prime_import,
>> .gem_prime_pin = amdgpu_gem_prime_pin,
>> .gem_prime_unpin = amdgpu_gem_prime_unpin,
>> .gem_prime_res_obj = amdgpu_gem_prime_res_obj,
>> @@ -843,6 +843,7 @@ static struct drm_driver kms_driver = {
>> .gem_prime_import_sg_table = amdgpu_gem_prime_import_sg_table,
>> .gem_prime_vmap = amdgpu_gem_prime_vmap,
>> .gem_prime_vunmap = amdgpu_gem_prime_vunmap,
>> + .gem_prime_mmap = amdgpu_gem_prime_mmap,
>> .name = DRIVER_NAME,
>> .desc = DRIVER_DESC,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> index 5b3f928..13c977a 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> @@ -57,6 +57,40 @@ void amdgpu_gem_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
>> ttm_bo_kunmap(&bo->dma_buf_vmap);
>> }
>> +int amdgpu_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
>> +{
>> + struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
>> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
>> + unsigned asize = amdgpu_bo_size(bo);
>> + int ret;
>> +
>> + if (!vma->vm_file)
>> + return -ENODEV;
>> +
>> + if (adev == NULL)
>> + return -ENODEV;
>> +
>> + /* Check for valid size. */
>> + if (asize < vma->vm_end - vma->vm_start)
>> + return -EINVAL;
>> +
>> + if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
>> + (bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)) {
>> + return -EPERM;
>> + }
>> + vma->vm_pgoff = amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;
>
> Maybe better use "vma->vm_pgoff += amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;", but I'm not sure.
>
> How other drivers handle this?
>
>> +
>> + /* prime mmap does not need to check access, so allow here */
>> + ret = drm_vma_node_allow(&obj->vma_node, vma->vm_file->private_data);
>> + if (ret)
>> + return ret;
>> +
>> + ret = ttm_bo_mmap(vma->vm_file, vma, &adev->mman.bdev);
>> + drm_vma_node_revoke(&obj->vma_node, vma->vm_file->private_data);
>> +
>> + return ret;
>> +}
>> +
>> struct drm_gem_object *
>> amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
>> struct dma_buf_attachment *attach,
>> @@ -130,14 +164,55 @@ struct reservation_object *amdgpu_gem_prime_res_obj(struct drm_gem_object *obj)
>> return bo->tbo.resv;
>> }
>> +static int amdgpu_gem_begin_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
>> +{
>> + return amdgpu_gem_prime_pin(dma_buf->priv);
>> +}
>> +
>> +static int amdgpu_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direction direction)
>> +{
>> + amdgpu_gem_prime_unpin(dma_buf->priv);
>> +
>> + return 0;
>> +}
>> +
>> +static struct dma_buf_ops amdgpu_dmabuf_ops;
>> +
>> struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>> struct drm_gem_object *gobj,
>> int flags)
>> {
>> struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
>> + struct dma_buf *dma_buf;
>> if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm))
>> return ERR_PTR(-EPERM);
>> - return drm_gem_prime_export(dev, gobj, flags);
>> + dma_buf = drm_gem_prime_export(dev, gobj, flags);
>> + amdgpu_dmabuf_ops = *(dma_buf->ops);
>> + amdgpu_dmabuf_ops.begin_cpu_access = amdgpu_gem_begin_cpu_access;
>> + amdgpu_dmabuf_ops.end_cpu_access = amdgpu_gem_end_cpu_access;
>> + dma_buf->ops = &amdgpu_dmabuf_ops;
>
> This isn't race free and needs to be fixed.
>
> Better add callbacks to drm_prime.c similar to drm_gem_dmabuf_mmap().
>
> Alternative you could just completely drop amdgpu_gem_begin_cpu_access() and amdgpu_gem_end_cpu_access() as well.
>
> When the buffer is shared between device it is pinned anyway and when it isn't shared ttm_bo_mmap() is able to handle VRAM mappings as well.
>
> Regards,
> Christian.
>
>> +
>> + return dma_buf;
>> +}
>> +
>> +struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
>> + struct dma_buf *dma_buf)
>> +{
>> + struct drm_gem_object *obj;
>> +
>> + if (dma_buf->ops == &amdgpu_dmabuf_ops) {
>> + obj = dma_buf->priv;
>> + if (obj->dev == dev) {
>> + /*
>> + * Importing dmabuf exported from out own gem increases
>> + * refcount on gem itself instead of f_count of dmabuf.
>> + */
>> + drm_gem_object_get(obj);
>> + return obj;
>> + }
>> + }
>> +
>> + return drm_gem_prime_import(dev, dma_buf);
>> }
>
>
More information about the amd-gfx
mailing list