[PATCH v2 09/12] drm/virtio: implement context init: allocate an array of fence contexts

[Gurchetan Singh]

We don't want fences from different 3D contexts (virgl, gfxstream,
venus) to be on the same timeline.  With explicit context creation,
we can specify the number of ring each context wants.

Execbuffer can specify which ring to use.

Note: virgl + Xserver + virtgpu KMS may need implicit sync
support in case a buffer object comes from a different context
type.  This can be added later when the revelant context types
support multiple rings, by waiting on the reservation object
associated with the foreign context's buffer object.

Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
Acked-by: Lingfeng Yang <lfy at google.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h   |  3 +++
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 34 ++++++++++++++++++++++++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index a5142d60c2fa..cca9ab505deb 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -56,6 +56,7 @@
 #define STATE_ERR 2
 
 #define MAX_CAPSET_ID 63
+#define MAX_RINGS 64
 
 struct virtio_gpu_object_params {
 	unsigned long size;
@@ -263,6 +264,8 @@ struct virtio_gpu_fpriv {
 	uint32_t ctx_id;
 	uint32_t context_init;
 	bool context_created;
+	uint32_t num_rings;
+	uint64_t base_fence_ctx;
 	struct mutex context_lock;
 };
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index f51f3393a194..262f79210283 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -99,6 +99,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 	int in_fence_fd = exbuf->fence_fd;
 	int out_fence_fd = -1;
 	void *buf;
+	uint64_t fence_ctx;
+	uint32_t ring_idx;
+
+	fence_ctx = vgdev->fence_drv.context;
+	ring_idx = 0;
 
 	if (vgdev->has_virgl_3d == false)
 		return -ENOSYS;
@@ -106,6 +111,17 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 	if ((exbuf->flags & ~VIRTGPU_EXECBUF_FLAGS))
 		return -EINVAL;
 
+	if ((exbuf->flags & VIRTGPU_EXECBUF_RING_IDX)) {
+		if (exbuf->ring_idx >= vfpriv->num_rings)
+			return -EINVAL;
+
+		if (!vfpriv->base_fence_ctx)
+			return -EINVAL;
+
+		fence_ctx = vfpriv->base_fence_ctx;
+		ring_idx = exbuf->ring_idx;
+	}
+
 	exbuf->fence_fd = -1;
 
 	virtio_gpu_create_context(dev, file);
@@ -173,7 +189,7 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
 			goto out_memdup;
 	}
 
-	out_fence = virtio_gpu_fence_alloc(vgdev, vgdev->fence_drv.context, 0);
+	out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
 	if(!out_fence) {
 		ret = -ENOMEM;
 		goto out_unresv;
@@ -691,7 +707,7 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 		return -EINVAL;
 
 	/* Number of unique parameters supported at this time. */
-	if (num_params > 1)
+	if (num_params > 2)
 		return -EINVAL;
 
 	ctx_set_params = memdup_user(u64_to_user_ptr(args->ctx_set_params),
@@ -731,6 +747,20 @@ static int virtio_gpu_context_init_ioctl(struct drm_device *dev,
 
 			vfpriv->context_init |= value;
 			break;
+		case VIRTGPU_CONTEXT_PARAM_NUM_RINGS:
+			if (vfpriv->base_fence_ctx) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+
+			if (value > MAX_RINGS) {
+				ret = -EINVAL;
+				goto out_unlock;
+			}
+
+			vfpriv->base_fence_ctx = dma_fence_context_alloc(value);
+			vfpriv->num_rings = value;
+			break;
 		default:
 			ret = -EINVAL;
 			goto out_unlock;
-- 
2.33.0.464.g1972c5931b-goog