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

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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: Jike Song <jike.song@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
This commit is contained in:
Jike Song 2016-12-16 10:51:06 +08:00 committed by Zhenyu Wang
parent faaaa53bdc
commit 364fb6b789
2 changed files with 22 additions and 3 deletions
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1
drivers/gpu/drm/i915/gvt/gvt.h
View File

@ -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
};

24
drivers/gpu/drm/i915/gvt/kvmgt.c
View File

@ -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 @@ out:
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;
}