Re: [PATCH] drm/i915/gvt: Add missing vfio_unregister_group_dev() call

[Alex Williamson]

On Thu, 29 Sep 2022 14:48:35 -0300
Jason Gunthorpe <j...@nvidia.com> wrote:

> When converting to directly create the vfio_device the mdev driver has to
> put a vfio_register_emulated_iommu_dev() in the probe() and a pairing
> vfio_unregister_group_dev() in the remove.
> 
> This was missed for gvt, add it.
> 
> Cc: sta...@vger.kernel.org
> Fixes: 978cf586ac35 ("drm/i915/gvt: convert to use 
> vfio_register_emulated_iommu_dev")
> Reported-by: Alex Williamson <alex.william...@redhat.com>
> Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> Should go through Alex's tree.
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c 
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 41bba40feef8f4..9003145adb5a93 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1615,6 +1615,7 @@ static void intel_vgpu_remove(struct mdev_device *mdev)
>       if (WARN_ON_ONCE(vgpu->attached))
>               return;
>  
> +     vfio_unregister_group_dev(&vgpu->vfio_device);
>       vfio_put_device(&vgpu->vfio_device);
>  }
>  
> 
> base-commit: c72e0034e6d4c36322d958b997d11d2627c6056c

This is marked for stable, but I think the stable backport for
existing kernels is actually:

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index e3cd58946477..de89946c4817 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -1595,6 +1595,9 @@ static void intel_vgpu_remove(struct mdev_device *mdev)
 
        if (WARN_ON_ONCE(vgpu->attached))
                return;
+
+       vfio_unregister_group_dev(&vgpu->vfio_device);
+       vfio_uninit_group_dev(&vgpu->vfio_device);
        intel_gvt_destroy_vgpu(vgpu);
 }