[PATCH v2 2/3] virtio-gpu: batch display update commands.

From: Gerd Hoffmann
Date: Thu Dec 12 2019 - 07:54:04 EST


When the driver submits multiple commands in a row it makes sense to
notify the host only after submitting the last one, so the host can
process them all at once, with a single vmexit.

Add functions to enable/disable notifications to allow that. Use the
new functions for primary plane updates.

Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 6 ++++++
drivers/gpu/drm/virtio/virtgpu_plane.c | 4 ++++
drivers/gpu/drm/virtio/virtgpu_vq.c | 23 +++++++++++++++++++++--
3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index eedae2a7b532..29cf005ed6b9 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -183,6 +183,9 @@ struct virtio_gpu_device {
struct kmem_cache *vbufs;
bool vqs_ready;

+ bool disable_notify;
+ bool pending_notify;
+
struct ida resource_ida;

wait_queue_head_t resp_wq;
@@ -335,6 +338,9 @@ void virtio_gpu_dequeue_ctrl_func(struct work_struct *work);
void virtio_gpu_dequeue_cursor_func(struct work_struct *work);
void virtio_gpu_dequeue_fence_func(struct work_struct *work);

+void virtio_gpu_disable_notify(struct virtio_gpu_device *vgdev);
+void virtio_gpu_enable_notify(struct virtio_gpu_device *vgdev);
+
/* virtio_gpu_display.c */
int virtio_gpu_framebuffer_init(struct drm_device *dev,
struct virtio_gpu_framebuffer *vgfb,
diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 59bf76d4a333..2fb068cd680e 100644
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -146,6 +146,8 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane,
return;
}

+ virtio_gpu_disable_notify(vgdev);
+
vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
bo = gem_to_virtio_gpu_obj(vgfb->base.obj[0]);
if (bo->dumb)
@@ -177,6 +179,8 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane,
plane->state->src_y >> 16,
plane->state->src_w >> 16,
plane->state->src_h >> 16);
+
+ virtio_gpu_enable_notify(vgdev);
}

static int virtio_gpu_cursor_prepare_fb(struct drm_plane *plane,
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 9274c4063c70..5914e79d3429 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -404,8 +404,12 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
}
notify = virtio_gpu_queue_ctrl_buffer_locked(vgdev, vbuf, vout);
spin_unlock(&vgdev->ctrlq.qlock);
- if (notify)
- virtqueue_notify(vgdev->ctrlq.vq);
+ if (notify) {
+ if (vgdev->disable_notify)
+ vgdev->pending_notify = true;
+ else
+ virtqueue_notify(vgdev->ctrlq.vq);
+ }

if (sgt) {
sg_free_table(sgt);
@@ -413,6 +417,21 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
}
}

+void virtio_gpu_disable_notify(struct virtio_gpu_device *vgdev)
+{
+ vgdev->disable_notify = true;
+}
+
+void virtio_gpu_enable_notify(struct virtio_gpu_device *vgdev)
+{
+ vgdev->disable_notify = false;
+
+ if (!vgdev->pending_notify)
+ return;
+ vgdev->pending_notify = false;
+ virtqueue_notify(vgdev->ctrlq.vq);
+}
+
static void virtio_gpu_queue_ctrl_buffer(struct virtio_gpu_device *vgdev,
struct virtio_gpu_vbuffer *vbuf)
{
--
2.18.1