[v2,1/2] drm/virtio: introduce the HOST_PAGE_SIZE feature

Commit Message

Sergio Lopez April 2, 2025, 5:46 p.m. UTC

Introduce a new feature, HOST_PAGE_SIZE, that indicates the host
provides its page size as a value in virtio_gpu_config.

Signed-off-by: Sergio Lopez <[e-mail]>
---
 drivers/gpu/drm/virtio/virtgpu_drv.c |  1 +
 drivers/gpu/drm/virtio/virtgpu_drv.h |  2 ++
 drivers/gpu/drm/virtio/virtgpu_kms.c | 13 ++++++++++---
 include/uapi/linux/virtio_gpu.h      |  5 +++++
 4 files changed, 18 insertions(+), 3 deletions(-)

Comments

Dmitry Osipenko April 2, 2025, 5:55 p.m. UTC | #1

On 4/2/25 20:46, Sergio Lopez wrote:
> diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
> index bf2c9cabd20793e3851e749baadf210341445501..adc264df4e458e9c754936c3015c069e5ee6b899 100644
> --- a/include/uapi/linux/virtio_gpu.h
> +++ b/include/uapi/linux/virtio_gpu.h
> @@ -64,6 +64,10 @@
>   * context_init and multiple timelines
>   */
>  #define VIRTIO_GPU_F_CONTEXT_INIT        4
> +/*
> + * Config struct contains host page size
> + */
> +#define VIRTIO_GPU_F_HOST_PAGE_SIZE      5
>  
>  enum virtio_gpu_ctrl_type {
>  	VIRTIO_GPU_UNDEFINED = 0,
> @@ -364,6 +368,7 @@ struct virtio_gpu_config {
>  	__le32 events_clear;
>  	__le32 num_scanouts;
>  	__le32 num_capsets;
> +	__le32 host_page_size;
>  };

Hi, this is still a spec change and the virtio-gpu spec update is need.
Please send the spec patch, I'd want to see that it won't have new
objections before merging the kernel patches.

Patch

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.c b/drivers/gpu/drm/virtio/virtgpu_drv.c
index 2d88e390feb468bf8783f13d90d0c4759dff0dcf..2e81aeaffdc6924dd88fb0778edef22084526866 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.c
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.c
@@ -154,6 +154,7 @@  static unsigned int features[] = {
 	VIRTIO_GPU_F_RESOURCE_UUID,
 	VIRTIO_GPU_F_RESOURCE_BLOB,
 	VIRTIO_GPU_F_CONTEXT_INIT,
+	VIRTIO_GPU_F_HOST_PAGE_SIZE,
 };
 static struct virtio_driver virtio_gpu_driver = {
 	.feature_table = features,
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index f17660a71a3e7a22b5d4fefa6b754c227a294037..439223b5f7cf8c9a120a28b7b7d57516928112e7 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -257,6 +257,7 @@  struct virtio_gpu_device {
 	bool has_resource_blob;
 	bool has_host_visible;
 	bool has_context_init;
+	bool has_host_page_size;
 	struct virtio_shm_region host_visible_region;
 	struct drm_mm host_visible_mm;
 
@@ -270,6 +271,7 @@  struct virtio_gpu_device {
 	uint32_t num_capsets;
 	uint64_t capset_id_mask;
 	struct list_head cap_cache;
+	uint32_t host_page_size;
 
 	/* protects uuid state when exporting */
 	spinlock_t resource_export_lock;
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 7dfb2006c561ca13b15d979ddb8bf2d753e35dad..4ab95712434615c2cc35f2ff80d33b40c4212cfb 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -123,7 +123,7 @@  int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 	struct virtio_gpu_device *vgdev;
 	/* this will expand later */
 	struct virtqueue *vqs[2];
-	u32 num_scanouts, num_capsets;
+	u32 num_scanouts, num_capsets, host_page_size;
 	int ret = 0;
 
 	if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
@@ -196,6 +196,12 @@  int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_CONTEXT_INIT)) {
 		vgdev->has_context_init = true;
 	}
+	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_HOST_PAGE_SIZE)) {
+		vgdev->has_host_page_size = true;
+		virtio_cread_le(vgdev->vdev, struct virtio_gpu_config,
+				host_page_size, &host_page_size);
+		vgdev->host_page_size = host_page_size;
+	}
 
 	DRM_INFO("features: %cvirgl %cedid %cresource_blob %chost_visible",
 		 vgdev->has_virgl_3d    ? '+' : '-',
@@ -203,8 +209,9 @@  int virtio_gpu_init(struct virtio_device *vdev, struct drm_device *dev)
 		 vgdev->has_resource_blob ? '+' : '-',
 		 vgdev->has_host_visible ? '+' : '-');
 
-	DRM_INFO("features: %ccontext_init\n",
-		 vgdev->has_context_init ? '+' : '-');
+	DRM_INFO("features: %ccontext_init %chost_page_size\n",
+		 vgdev->has_context_init ? '+' : '-',
+		 vgdev->has_host_page_size ? '+' : '-');
 
 	ret = virtio_find_vqs(vgdev->vdev, 2, vqs, vqs_info, NULL);
 	if (ret) {
diff --git a/include/uapi/linux/virtio_gpu.h b/include/uapi/linux/virtio_gpu.h
index bf2c9cabd20793e3851e749baadf210341445501..adc264df4e458e9c754936c3015c069e5ee6b899 100644
--- a/include/uapi/linux/virtio_gpu.h
+++ b/include/uapi/linux/virtio_gpu.h
@@ -64,6 +64,10 @@ 
  * context_init and multiple timelines
  */
 #define VIRTIO_GPU_F_CONTEXT_INIT        4
+/*
+ * Config struct contains host page size
+ */
+#define VIRTIO_GPU_F_HOST_PAGE_SIZE      5
 
 enum virtio_gpu_ctrl_type {
 	VIRTIO_GPU_UNDEFINED = 0,
@@ -364,6 +368,7 @@  struct virtio_gpu_config {
 	__le32 events_clear;
 	__le32 num_scanouts;
 	__le32 num_capsets;
+	__le32 host_page_size;
 };
 
 /* simple formats for fbcon/X use */