[PATCH] drm/i915/gvt: Activate/de-activate vGPU in mdev ops.
Zhenyu Wang
zhenyuw at linux.intel.com
Thu Mar 30 05:58:43 UTC 2017
On 2017.03.30 01:48:39 +0800, Zhi Wang wrote:
> 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 at intel.com>
> ---
applied to -fixes, thanks!
> drivers/gpu/drm/i915/gvt/gvt.c | 2 ++
> drivers/gpu/drm/i915/gvt/gvt.h | 5 ++++-
> drivers/gpu/drm/i915/gvt/kvmgt.c | 4 ++++
> drivers/gpu/drm/i915/gvt/vgpu.c | 43 +++++++++++++++++++++++++++++++++++-----
> 4 files changed, 48 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.c b/drivers/gpu/drm/i915/gvt/gvt.c
> index 3b9d59e..ef3baa0 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.c
> +++ b/drivers/gpu/drm/i915/gvt/gvt.c
> @@ -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,
> };
>
> /**
> diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
> index 2379192..2387eac 100644
> --- a/drivers/gpu/drm/i915/gvt/gvt.h
> +++ b/drivers/gpu/drm/i915/gvt/gvt.h
> @@ -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 *);
> };
>
>
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 3c5682a..59c59e4 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);
> diff --git a/drivers/gpu/drm/i915/gvt/vgpu.c b/drivers/gpu/drm/i915/gvt/vgpu.c
> index dfd2eff..fcd3c27 100644
> --- a/drivers/gpu/drm/i915/gvt/vgpu.c
> +++ b/drivers/gpu/drm/i915/gvt/vgpu.c
> @@ -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;
> --
> 2.7.4
>
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