[[iommufd] PATCH v3 1/2] i915/gvt: Move gvt mapping cache initialization to intel_vgpu_init_dev()

[Yi Liu]

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.

Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
Cc: Zhi Wang <zhi.a.wang at intel.com>
Cc: Kevin Tian <kevin.tian at intel.com>
Cc: intel-gvt-dev at lists.freedesktop.org
Reviewed-by: Zhi Wang <zhi.a.wang at intel.com>
Signed-off-by: Yi Liu <yi.l.liu at intel.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 7a45e5360caf..aaf0d9e8da95 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/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)
-- 
2.34.1