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Date:   Thu, 9 Jul 2020 11:58:00 +0200
From:   Halil Pasic <pasic@linux.ibm.com>
To:     Pierre Morel <pmorel@linux.ibm.com>
Cc:     linux-kernel@vger.kernel.org, borntraeger@de.ibm.com,
        frankja@linux.ibm.com, mst@redhat.com, jasowang@redhat.com,
        cohuck@redhat.com, kvm@vger.kernel.org, linux-s390@vger.kernel.org,
        virtualization@lists.linux-foundation.org, thomas.lendacky@amd.com,
        david@gibson.dropbear.id.au, linuxram@us.ibm.com,
        heiko.carstens@de.ibm.com, gor@linux.ibm.com
Subject: Re: [PATCH v5 1/2] virtio: let arch validate VIRTIO features
Message-ID: <20200709115800.7a6e93c8.pasic@linux.ibm.com>
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        <1594283959-13742-2-git-send-email-pmorel@linux.ibm.com>
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On Thu,  9 Jul 2020 10:39:18 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:

> An architecture may need to validate the VIRTIO devices features
> based on architecture specifics.
> 
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> Reviewed-by: Cornelia Huck <cohuck@redhat.com>
> Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>

Acked-by: Halil Pasic <pasic@linux.ibm.com>

> ---
>  drivers/virtio/virtio.c       | 19 +++++++++++++++++++
>  include/linux/virtio_config.h |  1 +
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> index a977e32a88f2..c4e14d46a5b6 100644
> --- a/drivers/virtio/virtio.c
> +++ b/drivers/virtio/virtio.c
> @@ -167,6 +167,21 @@ void virtio_add_status(struct virtio_device *dev, unsigned int status)
>  }
>  EXPORT_SYMBOL_GPL(virtio_add_status);
>  
> +/*
> + * arch_validate_virtio_features - provide arch specific hook when finalizing
> + *				   features for VIRTIO device dev
> + * @dev: the VIRTIO device being added
> + *
> + * Permits the platform to handle architecture-specific requirements when
> + * device features are finalized. This is the default implementation.
> + * Architecture implementations can override this.
> + */
> +
> +int __weak arch_validate_virtio_features(struct virtio_device *dev)
> +{
> +	return 0;
> +}
> +
>  int virtio_finalize_features(struct virtio_device *dev)
>  {
>  	int ret = dev->config->finalize_features(dev);
> @@ -176,6 +191,10 @@ int virtio_finalize_features(struct virtio_device *dev)
>  	if (ret)
>  		return ret;
>  
> +	ret = arch_validate_virtio_features(dev);
> +	if (ret)
> +		return ret;
> +
>  	if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1))
>  		return 0;
>  
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index bb4cc4910750..3f4117adf311 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -459,4 +459,5 @@ static inline void virtio_cwrite64(struct virtio_device *vdev,
>  		_r;							\
>  	})
>  
> +int arch_validate_virtio_features(struct virtio_device *dev);
>  #endif /* _LINUX_VIRTIO_CONFIG_H */