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Commit 364fb6b7 authored by Jike Song's avatar Jike Song Committed by Zhenyu Wang
Browse files

drm/i915/gvt/kvmgt: prevent double-release of vgpu 



The release action might be triggered from either user's closing
mdev or the detaching event of kvm and vfio_group, so this patch
introduces an atomic to prevent double-release.

Signed-off-by: default avatarJike Song <jike.song@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
parent faaaa53b

drivers/gpu/drm/i915/gvt/gvt.h

+1 −0
Original line number Diff line number Diff line
@@ -175,6 +175,7 @@ struct intel_vgpu { 
		struct notifier_block group_notifier;

		struct kvm *kvm;

		struct work_struct release_work;

		atomic_t released;

	} vdev;

#endif

};

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

+21 −3
Original line number Diff line number Diff line
@@ -500,7 +500,16 @@ static int intel_vgpu_open(struct mdev_device *mdev) 
		goto undo_iommu;

	}



	return kvmgt_guest_init(mdev);

	ret = kvmgt_guest_init(mdev);

	if (ret)

		goto undo_group;



	atomic_set(&vgpu->vdev.released, 0);

	return ret;



undo_group:

	vfio_unregister_notifier(&mdev->dev, VFIO_GROUP_NOTIFY,

					&vgpu->vdev.group_notifier);



undo_iommu:

	vfio_unregister_notifier(&mdev->dev, VFIO_IOMMU_NOTIFY,
@@ -512,17 +521,26 @@ static int intel_vgpu_open(struct mdev_device *mdev) 
static void __intel_vgpu_release(struct intel_vgpu *vgpu)

{

	struct kvmgt_guest_info *info;

	int ret;



	if (!handle_valid(vgpu->handle))

		return;



	vfio_unregister_notifier(&vgpu->vdev.mdev->dev, VFIO_IOMMU_NOTIFY,

	if (atomic_cmpxchg(&vgpu->vdev.released, 0, 1))

		return;



	ret = vfio_unregister_notifier(&vgpu->vdev.mdev->dev, VFIO_IOMMU_NOTIFY,

					&vgpu->vdev.iommu_notifier);

	vfio_unregister_notifier(&vgpu->vdev.mdev->dev, VFIO_GROUP_NOTIFY,

	WARN(ret, "vfio_unregister_notifier for iommu failed: %d\n", ret);



	ret = vfio_unregister_notifier(&vgpu->vdev.mdev->dev, VFIO_GROUP_NOTIFY,

					&vgpu->vdev.group_notifier);

	WARN(ret, "vfio_unregister_notifier for group failed: %d\n", ret);



	info = (struct kvmgt_guest_info *)vgpu->handle;

	kvmgt_guest_exit(info);



	vgpu->vdev.kvm = NULL;

	vgpu->handle = 0;

}