[PATCH v2] drm/vkms: prime import support

[Rodrigo Siqueira]

Hi Oleg,

First of all, thank you for keeping working on this feature. You did a
great job here. I just have a comments inline.

On 08/21, Oleg Vasilev wrote:
> Bring dmabuf sharing through implementing prime_import_sg_table callback.
> This will help to validate userspace conformance in prime configurations
> without using any actual hardware (e.g. in the cloud).
> 
> This enables kms_prime on vkms.
> 
> V2:
>  - Rodrigo: styleguide + return code check
> 
> Cc: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> Cc: Haneen Mohammed <hamohammed.sa at gmail.com>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Simon Ser <simon.ser at intel.com>
> Signed-off-by: Oleg Vasilev <oleg.vasilev at intel.com>
> ---
>  drivers/gpu/drm/vkms/vkms_drv.c | 12 +++++++++
>  drivers/gpu/drm/vkms/vkms_drv.h |  9 +++++++
>  drivers/gpu/drm/vkms/vkms_gem.c | 46 +++++++++++++++++++++++++++++++++
>  3 files changed, 67 insertions(+)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> index 44ab9f8ef8be..09598f949b9b 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> @@ -11,7 +11,9 @@
>  
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
> +#include <linux/dma-mapping.h>
>  
> +#include <drm/drm_gem.h>
>  #include <drm/drm_atomic.h>
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_drv.h>
> @@ -103,6 +105,8 @@ static struct drm_driver vkms_driver = {
>  	.gem_vm_ops		= &vkms_gem_vm_ops,
>  	.gem_free_object_unlocked = vkms_gem_free_object,
>  	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
> +	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
> +	.gem_prime_import_sg_table = vkms_prime_import_sg_table,
>  
>  	.name			= DRIVER_NAME,
>  	.desc			= DRIVER_DESC,
> @@ -157,6 +161,14 @@ static int __init vkms_init(void)
>  	if (ret)
>  		goto out_unregister;
>  
> +	ret = dma_coerce_mask_and_coherent(vkms_device->drm.dev,
> +					   DMA_BIT_MASK(64));
> +
> +	if (ret) {
> +		DRM_ERROR("Could not initialize DMA support\n");
> +		goto out_fini;
> +	}
> +
>  	vkms_device->drm.irq_enabled = true;
>  
>  	ret = drm_vblank_init(&vkms_device->drm, 1);
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 5a95100fa18b..6bf195c91097 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -126,6 +126,9 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
>  				       u32 *handle,
>  				       u64 size);
>  
> +struct vkms_gem_object *vkms_gem_create_private(struct drm_device *dev,
> +						u64 size);
> +
>  vm_fault_t vkms_gem_fault(struct vm_fault *vmf);
>  
>  int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
> @@ -137,6 +140,12 @@ int vkms_gem_vmap(struct drm_gem_object *obj);
>  
>  void vkms_gem_vunmap(struct drm_gem_object *obj);
>  
> +/* Prime */
> +struct drm_gem_object *
> +vkms_prime_import_sg_table(struct drm_device *dev,
> +			   struct dma_buf_attachment *attach,
> +			   struct sg_table *sg);
> +
>  /* CRC Support */
>  const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
>  					size_t *count);
> diff --git a/drivers/gpu/drm/vkms/vkms_gem.c b/drivers/gpu/drm/vkms/vkms_gem.c
> index 6489bfe0a149..b7565f48e054 100644
> --- a/drivers/gpu/drm/vkms/vkms_gem.c
> +++ b/drivers/gpu/drm/vkms/vkms_gem.c
> @@ -1,7 +1,9 @@
>  // SPDX-License-Identifier: GPL-2.0+
>  
> +#include <linux/dma-buf.h>
>  #include <linux/shmem_fs.h>
>  #include <linux/vmalloc.h>
> +#include <drm/drm_prime.h>
>  
>  #include "vkms_drv.h"
>  
> @@ -118,6 +120,25 @@ struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
>  	return &obj->gem;
>  }
>  
> +struct vkms_gem_object *vkms_gem_create_private(struct drm_device *dev,
> +						u64 size)
> +{
> +	struct vkms_gem_object *obj;
> +
> +	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +
> +	if (!obj)
> +		return ERR_PTR(-ENOMEM);
> +
> +	size = roundup(size, PAGE_SIZE);
> +
> +	drm_gem_private_object_init(dev, &obj->gem, size);
> +
> +	mutex_init(&obj->pages_lock);
> +
> +	return obj;
> +}
> +

I suppose that any other function or helper do not invoke this function,
am I right?

If so, I recommend you to remove it from this patch. IMHO, add a
function that is not used yet may make the code hard to understand and
maintain.

Thanks

>  int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
>  		     struct drm_mode_create_dumb *args)
>  {
> @@ -218,3 +239,28 @@ int vkms_gem_vmap(struct drm_gem_object *obj)
>  	mutex_unlock(&vkms_obj->pages_lock);
>  	return ret;
>  }
> +
> +struct drm_gem_object *
> +vkms_prime_import_sg_table(struct drm_device *dev,
> +			   struct dma_buf_attachment *attach,
> +			   struct sg_table *sg)
> +{
> +	struct vkms_gem_object *obj;
> +	int npages;
> +
> +	obj = __vkms_gem_create(dev, attach->dmabuf->size);
> +	if (IS_ERR(obj))
> +		return ERR_CAST(obj);
> +
> +	npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
> +	DRM_DEBUG_PRIME("Importing %d pages\n", npages);
> +
> +	obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
> +	if (!obj->pages) {
> +		vkms_gem_free_object(&obj->gem);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	drm_prime_sg_to_page_addr_arrays(sg, obj->pages, NULL, npages);
> +	return &obj->gem;
> +}
> -- 
> 2.23.0
> 

-- 
Rodrigo Siqueira
Software Engineer, Advanced Micro Devices (AMD)
https://siqueira.tech
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <https://lists.freedesktop.org/archives/dri-devel/attachments/20190903/99bd620e/attachment.sig>