drm/i915/gvt: Dmabuf support for GVT-g

This patch introduces a guest's framebuffer sharing mechanism based on
dma-buf subsystem. With this sharing mechanism, guest's framebuffer can
be shared between guest VM and host.

v17:
- modify VFIO_DEVICE_GET_GFX_DMABUF interface. (Alex)

v16:
- add x_hot and y_hot. (Gerd)
- add flag validation for VFIO_DEVICE_GET_GFX_DMABUF. (Alex)
- rebase 4.14.0-rc6.

v15:
- add VFIO_DEVICE_GET_GFX_DMABUF ABI. (Gerd)
- add intel_vgpu_dmabuf_cleanup() to clean up the vGPU's dmabuf. (Gerd)

v14:
- add PROBE, DMABUF and REGION flags. (Alex)

v12:
- refine the lifecycle of dmabuf.

v9:
- remove dma-buf management. (Alex)
- track the dma-buf create and release in kernel mode. (Gerd) (Daniel)

v8:
- refine the dma-buf ioctl definition.(Alex)
- add a lock to protect the dmabuf list. (Alex)

v7:
- release dma-buf related allocations in dma-buf's associated release
  function. (Alex)
- refine ioctl interface for querying plane info or create dma-buf.
  (Alex)

v6:
- align the dma-buf life cycle with the vfio device. (Alex)
- add the dma-buf related operations in a separate patch. (Gerd)
- i915 related changes. (Chris)

v5:
- fix bug while checking whether the gem obj is gvt's dma-buf when user
  change caching mode or domains. Add a helper function to do it.
  (Xiaoguang)
- add definition for the query plane and create dma-buf. (Xiaoguang)

v4:
- fix bug while checking whether the gem obj is gvt's dma-buf when set
  caching mode or doamins. (Xiaoguang)

v3:
- declare a new flag I915_GEM_OBJECT_IS_GVT_DMABUF in drm_i915_gem_object
  to represent the gem obj for gvt's dma-buf. The tiling mode, caching
  mode and domains can not be changed for this kind of gem object. (Alex)
- change dma-buf related information to be more generic. So other vendor
  can use the same interface. (Alex)

v2:
- create a management fd for dma-buf operations. (Alex)
- alloc gem object's backing storage in gem obj's get_pages() callback.
  (Chris)

Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index e0cda45ac6c2..b8a85e08091a 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -377,10 +377,23 @@ static int intel_vgpu_register_reg(struct intel_vgpu *vgpu,
 	vgpu->vdev.region[vgpu->vdev.num_regions].flags = flags;
 	vgpu->vdev.region[vgpu->vdev.num_regions].data = data;
 	vgpu->vdev.num_regions++;
+	return 0;
+}
+
+static int kvmgt_get_vfio_device(void *p_vgpu)
+{
+	struct intel_vgpu *vgpu = (struct intel_vgpu *)p_vgpu;
 
+	vgpu->vdev.vfio_device = vfio_device_get_from_dev(
+		mdev_dev(vgpu->vdev.mdev));
+	if (!vgpu->vdev.vfio_device) {
+		gvt_vgpu_err("failed to get vfio device\n");
+		return -ENODEV;
+	}
 	return 0;
 }
 
+
 static int kvmgt_set_opregion(void *p_vgpu)
 {
 	struct intel_vgpu *vgpu = (struct intel_vgpu *)p_vgpu;
@@ -409,6 +422,14 @@ static int kvmgt_set_opregion(void *p_vgpu)
 	return ret;
 }
 
+static void kvmgt_put_vfio_device(void *vgpu)
+{
+	if (WARN_ON(!((struct intel_vgpu *)vgpu)->vdev.vfio_device))
+		return;
+
+	vfio_device_put(((struct intel_vgpu *)vgpu)->vdev.vfio_device);
+}
+
 static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
 {
 	struct intel_vgpu *vgpu = NULL;
@@ -1146,6 +1167,33 @@ static long intel_vgpu_ioctl(struct mdev_device *mdev, unsigned int cmd,
 	} else if (cmd == VFIO_DEVICE_RESET) {
 		intel_gvt_ops->vgpu_reset(vgpu);
 		return 0;
+	} else if (cmd == VFIO_DEVICE_QUERY_GFX_PLANE) {
+		struct vfio_device_gfx_plane_info dmabuf;
+		int ret = 0;
+
+		minsz = offsetofend(struct vfio_device_gfx_plane_info,
+				    dmabuf_id);
+		if (copy_from_user(&dmabuf, (void __user *)arg, minsz))
+			return -EFAULT;
+		if (dmabuf.argsz < minsz)
+			return -EINVAL;
+
+		ret = intel_gvt_ops->vgpu_query_plane(vgpu, &dmabuf);
+		if (ret != 0)
+			return ret;
+
+		return copy_to_user((void __user *)arg, &dmabuf, minsz) ?
+								-EFAULT : 0;
+	} else if (cmd == VFIO_DEVICE_GET_GFX_DMABUF) {
+		__u32 dmabuf_id;
+		__s32 dmabuf_fd;
+
+		if (get_user(dmabuf_id, (__u32 __user *)arg))
+			return -EFAULT;
+
+		dmabuf_fd = intel_gvt_ops->vgpu_get_dmabuf(vgpu, dmabuf_id);
+		return dmabuf_fd;
+
 	}
 
 	return 0;
@@ -1387,6 +1435,9 @@ static int kvmgt_guest_init(struct mdev_device *mdev)
 	kvmgt_protect_table_init(info);
 	gvt_cache_init(vgpu);
 
+	mutex_init(&vgpu->dmabuf_lock);
+	init_completion(&vgpu->vblank_done);
+
 	info->track_node.track_write = kvmgt_page_track_write;
 	info->track_node.track_flush_slot = kvmgt_page_track_flush_slot;
 	kvm_page_track_register_notifier(kvm, &info->track_node);
@@ -1528,6 +1579,8 @@ struct intel_gvt_mpt kvmgt_mpt = {
 	.write_gpa = kvmgt_write_gpa,
 	.gfn_to_mfn = kvmgt_gfn_to_pfn,
 	.set_opregion = kvmgt_set_opregion,
+	.get_vfio_device = kvmgt_get_vfio_device,
+	.put_vfio_device = kvmgt_put_vfio_device,
 };
 EXPORT_SYMBOL_GPL(kvmgt_mpt);