drm/i915/gvt: Activate/de-activate vGPU in mdev ops.
This patch introduces two functions for activating/de-activating vGPU in
mdev ops.
A racing condition was found between virtual vblank emulation and KVGMT
mdev release path. V-blank emulation will emulate and inject V-blank
interrupt for every active vGPU with holding gvt->lock, while in mdev
release path, it will directly release hypervisor handle without changing
vGPU status or taking gvt->lock, so a kernel oops is encountered when
vblank emulation is injecting a interrupt with a invalid hypervisor
handle. (Reported by Terrence)
To solve this problem, we factor out vGPU activation/de-activation from
vGPU creation/destruction path and let KVMGT mdev release ops de-activate
the vGPU before release hypervisor handle. Once a vGPU is de-activated,
GVT-g will not emulate v-blank for it or touch the hypervisor handle.
Fixes: 659643f ("drm/i915/gvt/kvmgt: add vfio/mdev support to KVMGT")
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index d641214..9843d74 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -544,6 +544,8 @@ static int intel_vgpu_open(struct mdev_device *mdev)
if (ret)
goto undo_group;
+ intel_gvt_ops->vgpu_activate(vgpu);
+
atomic_set(&vgpu->vdev.released, 0);
return ret;
@@ -569,6 +571,8 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
if (atomic_cmpxchg(&vgpu->vdev.released, 0, 1))
return;
+ intel_gvt_ops->vgpu_deactivate(vgpu);
+
ret = vfio_unregister_notifier(mdev_dev(vgpu->vdev.mdev), VFIO_IOMMU_NOTIFY,
&vgpu->vdev.iommu_notifier);
WARN(ret, "vfio_unregister_notifier for iommu failed: %d\n", ret);