Re: [PATCH v2] drm/vkms: prime import support

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@gmail.com Cc: Haneen Mohammed hamohammed.sa@gmail.com Cc: Daniel Vetter daniel@ffwll.ch Cc: Simon Ser simon.ser@intel.com Signed-off-by: Oleg Vasilev oleg.vasilev@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