From 210b318521a1a2b40767ec365e90c156ee15edb8 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Fri, 7 Feb 2020 07:46:53 +0100
Subject: drm/virtio: fix ring free check
Git-commit: 5edbb56082567d754a096286368e99a3377d8c95
Patch-mainline: v5.7-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

If the virtio device supports indirect ring descriptors we need only one
ring entry for the whole command.  Take that into account when checking
whenever the virtqueue has enough free entries for our command.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200207064653.14403-1-kraxel@redhat.com
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/virtio/virtgpu_debugfs.c | 1 +
 drivers/gpu/drm/virtio/virtgpu_drv.h     | 1 +
 drivers/gpu/drm/virtio/virtgpu_kms.c     | 3 +++
 drivers/gpu/drm/virtio/virtgpu_vq.c      | 3 +++
 4 files changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_debugfs.c b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
index 5156e6b279db..e27120d512b0 100644
--- a/drivers/gpu/drm/virtio/virtgpu_debugfs.c
+++ b/drivers/gpu/drm/virtio/virtgpu_debugfs.c
@@ -47,6 +47,7 @@ static int virtio_gpu_features(struct seq_file *m, void *data)
 
 	virtio_add_bool(m, "virgl", vgdev->has_virgl_3d);
 	virtio_add_bool(m, "edid", vgdev->has_edid);
+	virtio_add_bool(m, "indirect", vgdev->has_indirect);
 	virtio_add_int(m, "cap sets", vgdev->num_capsets);
 	virtio_add_int(m, "scanouts", vgdev->num_scanouts);
 	return 0;
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 7e69c06e168e..d278c8c50f39 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -193,6 +193,7 @@ struct virtio_gpu_device {
 
 	bool has_virgl_3d;
 	bool has_edid;
+	bool has_indirect;
 
 	struct work_struct config_changed_work;
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 2f5773e43557..c1086df49816 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
@@ -159,6 +159,9 @@ int virtio_gpu_init(struct drm_device *dev)
 	if (virtio_has_feature(vgdev->vdev, VIRTIO_GPU_F_EDID)) {
 		vgdev->has_edid = true;
 	}
+	if (virtio_has_feature(vgdev->vdev, VIRTIO_RING_F_INDIRECT_DESC)) {
+		vgdev->has_indirect = true;
+	}
 
 	DRM_INFO("features: %cvirgl %cedid\n",
 		 vgdev->has_virgl_3d ? '+' : '-',
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 41e475fbd67b..cc02fc4bab2a 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -330,6 +330,9 @@ static void virtio_gpu_queue_ctrl_sgs(struct virtio_gpu_device *vgdev,
 	bool notify = false;
 	int ret;
 
+	if (vgdev->has_indirect)
+		elemcnt = 1;
+
 again:
 	spin_lock(&vgdev->ctrlq.qlock);
 
-- 
2.28.0