Re: [PATCH v2] drm/virtio: Align host mapping request to maximum platform page size

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi


Am 25.01.25 um 22:08 schrieb Sasha Finkelstein via B4 Relay:
> From: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
>
> This allows running different page sizes between host and guest on
> platforms that support mixed page sizes.
>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@xxxxxxxxx>
> ---
> Changes in v2:
> - Aligned all object sizes to MAX_PAGE_SIZE too.
> - Link to v1: https://lore.kernel.org/r/20250109-virtgpu-mixed-page-size-v1-1-c8fe1e1859f3@xxxxxxxxx
> ---
>   drivers/gpu/drm/virtio/virtgpu_drv.h    | 6 ++++++
>   drivers/gpu/drm/virtio/virtgpu_gem.c    | 2 +-
>   drivers/gpu/drm/virtio/virtgpu_ioctl.c  | 2 +-
>   drivers/gpu/drm/virtio/virtgpu_object.c | 2 +-
>   drivers/gpu/drm/virtio/virtgpu_vram.c   | 4 ++--
>   5 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
> index 64c236169db88acd6ba9afd20a1ab16c667490c4..b73844d6535e45402dc46898035eaa7492de935d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_drv.h
> +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
> @@ -61,6 +61,12 @@
>   /* See virtio_gpu_ctx_create. One additional character for NULL terminator. */
>   #define DEBUG_NAME_MAX_LEN 65
>   
> +#if defined(__powerpc64__) || defined(__aarch64__) || defined(__mips__) || defined(__loongarch__)
> +#define MAX_PAGE_SIZE SZ_64K
> +#else
> +#define MAX_PAGE_SIZE PAGE_SIZE
> +#endif

This is per-architecture code and does not belong in a DRM driver.

Best regards
Thomas

> +
>   struct virtio_gpu_object_params {
>   	unsigned long size;
>   	bool dumb;
> diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
> index 7db48d17ee3a8a9c638a8c6f9e58f35bd004b453..8e625ccae308f46b11a390a0987fd5ea55ccbf8d 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_gem.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
> @@ -73,7 +73,7 @@ int virtio_gpu_mode_dumb_create(struct drm_file *file_priv,
>   
>   	pitch = args->width * 4;
>   	args->size = pitch * args->height;
> -	args->size = ALIGN(args->size, PAGE_SIZE);
> +	args->size = ALIGN(args->size, MAX_PAGE_SIZE);
>   
>   	params.format = virtio_gpu_translate_format(DRM_FORMAT_HOST_XRGB8888);
>   	params.width = args->width;
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index e4f76f31555049369000a50c0cb1d5edab68536b..e39ae008ac5f734ec52e9703413958b4ea4be7d6 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -167,7 +167,7 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
>   	params.size = rc->size;
>   	/* allocate a single page size object */
>   	if (params.size == 0)
> -		params.size = PAGE_SIZE;
> +		params.size = MAX_PAGE_SIZE;
>   
>   	fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
>   	if (!fence)
> diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
> index c7e74cf130221bbed3aa447e416065b03bf3e2b4..5aab82028293b7d73bcc4e686e7e2ecba6108b7b 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_object.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_object.c
> @@ -190,7 +190,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
>   
>   	*bo_ptr = NULL;
>   
> -	params->size = roundup(params->size, PAGE_SIZE);
> +	params->size = roundup(params->size, MAX_PAGE_SIZE);
>   	shmem_obj = drm_gem_shmem_create(vgdev->ddev, params->size);
>   	if (IS_ERR(shmem_obj))
>   		return PTR_ERR(shmem_obj);
> diff --git a/drivers/gpu/drm/virtio/virtgpu_vram.c b/drivers/gpu/drm/virtio/virtgpu_vram.c
> index 25df81c027837c248a746e41856b5aa7e216b8d5..18e773b036f7c8190d4e20ad3f2c85c36e7e295c 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_vram.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_vram.c
> @@ -150,8 +150,8 @@ static int virtio_gpu_vram_map(struct virtio_gpu_object *bo)
>   		return -EINVAL;
>   
>   	spin_lock(&vgdev->host_visible_lock);
> -	ret = drm_mm_insert_node(&vgdev->host_visible_mm, &vram->vram_node,
> -				 bo->base.base.size);
> +	ret = drm_mm_insert_node_generic(&vgdev->host_visible_mm, &vram->vram_node,
> +					 bo->base.base.size, MAX_PAGE_SIZE, 0, 0);
>   	spin_unlock(&vgdev->host_visible_lock);
>   
>   	if (ret)
>
> ---
> base-commit: 643e2e259c2b25a2af0ae4c23c6e16586d9fd19c
> change-id: 20250109-virtgpu-mixed-page-size-282b8f4a02fc

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)