[PATCH] drm/i915/gvt: Dereference msi eventfd_ctx when it isn't used anymore

[Zhenyu Wang]

On 2018.03.27 05:29:08 +0800, Xiong Zhang wrote:
> kvmgt get msi eventfd_ctx at qemu vfio set irq eventfd, then
> msi eventfd_ctx should be put at some point.
> The first point is kvmgt handle qemu vfio_disable_irqindex()
> call which has DATA_NONE and ACTION_TRIGGER in flags.
> If qemu doesn't call vfio_disable_irqindex(), the second point
> is vgpu release function.
> 
> Signed-off-by: Xiong Zhang <xiong.y.zhang at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index c16a492..3162820 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -583,6 +583,17 @@ static int intel_vgpu_open(struct mdev_device *mdev)
>  	return ret;
>  }
>  
> +static void intel_vgpu_release_msi_eventfd_ctx(struct intel_vgpu *vgpu)
> +{
> +	struct eventfd_ctx *trigger;
> +
> +	trigger = vgpu->vdev.msi_trigger;
> +	if (trigger) {
> +		eventfd_ctx_put(trigger);
> +		vgpu->vdev.msi_trigger = NULL;
> +	}
> +}
> +
>  static void __intel_vgpu_release(struct intel_vgpu *vgpu)
>  {
>  	struct kvmgt_guest_info *info;
> @@ -607,6 +618,8 @@ static void __intel_vgpu_release(struct intel_vgpu *vgpu)
>  	info = (struct kvmgt_guest_info *)vgpu->handle;
>  	kvmgt_guest_exit(info);
>  
> +	intel_vgpu_release_msi_eventfd_ctx(vgpu);
> +
>  	vgpu->vdev.kvm = NULL;
>  	vgpu->handle = 0;
>  }
> @@ -987,7 +1000,8 @@ static int intel_vgpu_set_msi_trigger(struct intel_vgpu *vgpu,
>  			return PTR_ERR(trigger);
>  		}
>  		vgpu->vdev.msi_trigger = trigger;
> -	}
> +	} else if ((flags & VFIO_IRQ_SET_DATA_NONE) && !count)
> +		intel_vgpu_release_msi_eventfd_ctx(vgpu);
>  
>  	return 0;
>  }
> -- 

Looks good to me, applied, thanks!

-- 
Open Source Technology Center, Intel ltd.

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