Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c0f5c096-3cab-1df4-6cc5-7f4c42271fc0@linux.ibm.com>
Date:   Fri, 21 Oct 2022 12:46:49 -0400
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.3.1
Subject: Re: [PATCH] s390/vfio-ap: Fix memory allocation for mdev_types array
Content-Language: en-US
To:     "Jason J. Herne" <jjherne@linux.ibm.com>,
        linux-s390@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org, Christoph Hellwig <hch@infradead.org>
References: <20221021145905.15100-1-jjherne@linux.ibm.com>
From:   Matthew Rosato <mjrosato@linux.ibm.com>
In-Reply-To: <20221021145905.15100-1-jjherne@linux.ibm.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10/21/22 10:59 AM, Jason J. Herne wrote:
> The vfio-ap crypto driver fails to allocate memory for an array of
> pointers used to pass supported mdev types to mdev_register_parent().
> 
> Since we only support a single mdev type, the fix is to allocate a
> single entry in the ap_matrix_dev->mdev_types array.
> 
> Fixes: 63e685747784 ("s390: vfio-ap: base implementation of VFIO AP device driver")

I think you want

Fixes: da44c340c4fe ("vfio/mdev: simplify mdev_type handling")

Where *mdev_types[] was introduced.  The fix you propose is the same way Christoph (added to CC) handled vfio-ccw, LGTM.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

> Cc: stable@vger.kernel.org
> Cc: Tony Krowiak <akrowiak@linux.ibm.com>
> Reported-by: Christian Borntraeger <borntraeger@linux.ibm.com>
> Signed-off-by: Jason J. Herne <jjherne@linux.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_private.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
> index 2eddd5f34ed3..976a65f32e7d 100644
> --- a/drivers/s390/crypto/vfio_ap_private.h
> +++ b/drivers/s390/crypto/vfio_ap_private.h
> @@ -52,7 +52,7 @@ struct ap_matrix_dev {
>  	struct mutex guests_lock; /* serializes access to each KVM guest */
>  	struct mdev_parent parent;
>  	struct mdev_type mdev_type;
> -	struct mdev_type *mdev_types[];
> +	struct mdev_type *mdev_types[1];
>  };
>  
>  extern struct ap_matrix_dev *matrix_dev;