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

From: Sasha Finkelstein <redacted>

This allows running different page sizes between host and guest on
platforms that support mixed page sizes.

Signed-off-by: Sasha Finkelstein <redacted>
---
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@gmail.com (local)
---
  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

+
  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