i915/gvt: Move gvt mapping cache initialization to intel_vgpu_init_dev()

vfio container registers .dma_unmap() callback after the device is opened.
So it's fine for mdev drivers to initialize internal mapping cache in
.open_device(). See vfio_device_container_register().

Now with iommufd an access ops with an unmap callback is registered when
the device is bound to iommufd which is before .open_device() is
called. This implies gvt's .dma_unmap() could be called before its
internal mapping cache is initialized.

The fix is moving gvt mapping cache initialization to vGPU init. While at
it also move ptable initialization together.

Link: https://lore.kernel.org/r/20221202135402.756470-2-yi.l.liu@intel.comReviewed-by: NZhi Wang <zhi.a.wang@intel.com>
Reviewed-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: NYi Liu <yi.l.liu@intel.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -671,9 +671,6 @@ static int intel_vgpu_open_device(struct vfio_device *vfio_dev)
 
 	vgpu->attached = true;
 
-	kvmgt_protect_table_init(vgpu);
-	gvt_cache_init(vgpu);
-
 	vgpu->track_node.track_write = kvmgt_page_track_write;
 	vgpu->track_node.track_flush_slot = kvmgt_page_track_flush_slot;
 	kvm_page_track_register_notifier(vgpu->vfio_device.kvm,
@@ -718,6 +715,11 @@ static void intel_vgpu_close_device(struct vfio_device *vfio_dev)
 	kvmgt_protect_table_destroy(vgpu);
 	gvt_cache_destroy(vgpu);
 
+	WARN_ON(vgpu->nr_cache_entries);
+
+	vgpu->gfn_cache = RB_ROOT;
+	vgpu->dma_addr_cache = RB_ROOT;
+
 	intel_vgpu_release_msi_eventfd_ctx(vgpu);
 
 	vgpu->attached = false;
@@ -1451,9 +1453,17 @@ static int intel_vgpu_init_dev(struct vfio_device *vfio_dev)
 	struct intel_vgpu *vgpu = vfio_dev_to_vgpu(vfio_dev);
 	struct intel_vgpu_type *type =
 		container_of(mdev->type, struct intel_vgpu_type, type);
+	int ret;
 
 	vgpu->gvt = kdev_to_i915(mdev->type->parent->dev)->gvt;
-	return intel_gvt_create_vgpu(vgpu, type->conf);
+	ret = intel_gvt_create_vgpu(vgpu, type->conf);
+	if (ret)
+		return ret;
+
+	kvmgt_protect_table_init(vgpu);
+	gvt_cache_init(vgpu);
+
+	return 0;
 }
 
 static void intel_vgpu_release_dev(struct vfio_device *vfio_dev)