[PATCH v4 4/7] drm/i915/gvt: hold reference of VFIO group during opening of vgpu

Yan Zhao
2020-03-13T03:20:02Z

hold reference count of the VFIO group for each vgpu at vgpu opening and
release the reference at vgpu releasing.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
drivers/gpu/drm/i915/gvt/kvmgt.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 074c4efb58eb..811cee28ae06 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -131,6 +131,7 @@ struct kvmgt_vdev {
struct work_struct release_work;
atomic_t released;
struct vfio_device *vfio_device;
+ struct vfio_group *vfio_group;
};

static inline struct kvmgt_vdev *kvmgt_vdev(struct intel_vgpu *vgpu)
@@ -792,6 +793,7 @@ static int intel_vgpu_open(struct mdev_device *mdev)
struct kvmgt_vdev *vdev = kvmgt_vdev(vgpu);
unsigned long events;
int ret;
+ struct vfio_group *vfio_group;

vdev->iommu_notifier.notifier_call = intel_vgpu_iommu_notifier;
vdev->group_notifier.notifier_call = intel_vgpu_group_notifier;
@@ -814,6 +816,14 @@ static int intel_vgpu_open(struct mdev_device *mdev)
goto undo_iommu;
}

+ vfio_group = vfio_group_get_external_user_from_dev(mdev_dev(mdev));
+ if (IS_ERR_OR_NULL(vfio_group)) {
+ ret = !vfio_group ? -EFAULT : PTR_ERR(vfio_group);
+ gvt_vgpu_err("vfio_group_get_external_user_from_dev failed\n");
+ goto undo_register;
+ }
+ vdev->vfio_group = vfio_group;
+
/* Take a module reference as mdev core doesn't take
* a reference for vendor driver.
*/
@@ -830,6 +840,10 @@ static int intel_vgpu_open(struct mdev_device *mdev)
return ret;

undo_group:
+ vfio_group_put_external_user(vdev->vfio_group);
+ vdev->vfio_group = NULL;
+
+undo_register:
vfio_unregister_notifier(mdev_dev(mdev), VFIO_GROUP_NOTIFY,
&vdev->group_notifier);

@@ -884,6 +898,7 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
kvmgt_guest_exit(info);

intel_vgpu_release_msi_eventfd_ctx(vgpu);
+ vfio_group_put_external_user(vdev->vfio_group);

vdev->kvm = NULL;
vgpu->handle = 0;
--
2.17.1