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Commit b79c52ae authored by Zhi Wang's avatar Zhi Wang Committed by Zhenyu Wang
Browse files

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: 659643f7 ("drm/i915/gvt/kvmgt: add vfio/mdev support to KVMGT")
Signed-off-by: default avatarZhi Wang <zhi.a.wang@intel.com>
Signed-off-by: default avatarZhenyu Wang <zhenyuw@linux.intel.com>
parent bc2d4b62

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

+2 −0
Original line number Diff line number Diff line
@@ -52,6 +52,8 @@ static const struct intel_gvt_ops intel_gvt_ops = { 
	.vgpu_create = intel_gvt_create_vgpu,

	.vgpu_destroy = intel_gvt_destroy_vgpu,

	.vgpu_reset = intel_gvt_reset_vgpu,

	.vgpu_activate = intel_gvt_activate_vgpu,

	.vgpu_deactivate = intel_gvt_deactivate_vgpu,

};



/**

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

+4 −1
Original line number Diff line number Diff line
@@ -382,7 +382,8 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu); 
void intel_gvt_reset_vgpu_locked(struct intel_vgpu *vgpu, bool dmlr,

				 unsigned int engine_mask);

void intel_gvt_reset_vgpu(struct intel_vgpu *vgpu);



void intel_gvt_activate_vgpu(struct intel_vgpu *vgpu);

void intel_gvt_deactivate_vgpu(struct intel_vgpu *vgpu);



/* validating GM functions */

#define vgpu_gmadr_is_aperture(vgpu, gmadr) \
@@ -449,6 +450,8 @@ struct intel_gvt_ops { 
				struct intel_vgpu_type *);

	void (*vgpu_destroy)(struct intel_vgpu *);

	void (*vgpu_reset)(struct intel_vgpu *);

	void (*vgpu_activate)(struct intel_vgpu *);

	void (*vgpu_deactivate)(struct intel_vgpu *);

};

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

+4 −0
Original line number Diff line number Diff line
@@ -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);

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

+38 −5
Original line number Diff line number Diff line
@@ -179,20 +179,34 @@ static void intel_gvt_update_vgpu_types(struct intel_gvt *gvt) 
}



/**

 * intel_gvt_destroy_vgpu - destroy a virtual GPU

 * intel_gvt_active_vgpu - activate a virtual GPU

 * @vgpu: virtual GPU

 *

 * This function is called when user wants to destroy a virtual GPU.

 * This function is called when user wants to activate a virtual GPU.

 *

 */

void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)

void intel_gvt_activate_vgpu(struct intel_vgpu *vgpu)

{

	mutex_lock(&vgpu->gvt->lock);

	vgpu->active = true;

	mutex_unlock(&vgpu->gvt->lock);

}



/**

 * intel_gvt_deactive_vgpu - deactivate a virtual GPU

 * @vgpu: virtual GPU

 *

 * This function is called when user wants to deactivate a virtual GPU.

 * All virtual GPU runtime information will be destroyed.

 *

 */

void intel_gvt_deactivate_vgpu(struct intel_vgpu *vgpu)

{

	struct intel_gvt *gvt = vgpu->gvt;



	mutex_lock(&gvt->lock);



	vgpu->active = false;

	idr_remove(&gvt->vgpu_idr, vgpu->id);



	if (atomic_read(&vgpu->running_workload_num)) {

		mutex_unlock(&gvt->lock);
@@ -201,6 +215,26 @@ void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu) 
	}



	intel_vgpu_stop_schedule(vgpu);



	mutex_unlock(&gvt->lock);

}



/**

 * intel_gvt_destroy_vgpu - destroy a virtual GPU

 * @vgpu: virtual GPU

 *

 * This function is called when user wants to destroy a virtual GPU.

 *

 */

void intel_gvt_destroy_vgpu(struct intel_vgpu *vgpu)

{

	struct intel_gvt *gvt = vgpu->gvt;



	mutex_lock(&gvt->lock);



	WARN(vgpu->active, "vGPU is still active!\n");



	idr_remove(&gvt->vgpu_idr, vgpu->id);

	intel_vgpu_clean_sched_policy(vgpu);

	intel_vgpu_clean_gvt_context(vgpu);

	intel_vgpu_clean_execlist(vgpu);
@@ -277,7 +311,6 @@ static struct intel_vgpu *__intel_gvt_create_vgpu(struct intel_gvt *gvt, 
	if (ret)

		goto out_clean_shadow_ctx;



	vgpu->active = true;

	mutex_unlock(&gvt->lock);



	return vgpu;