[PATCH] s390/vfio-ap: Fix memory allocation for mdev_types array

[PATCH] s390/vfio-ap: Fix memory allocation for mdev_types array

[Jason J. Herne]

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")
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;
-- 
2.37.3

Re: [PATCH] s390/vfio-ap: Fix memory allocation for mdev_types array

[Matthew Rosato]

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;

Re: [PATCH] s390/vfio-ap: Fix memory allocation for mdev_types array

[Christian Borntraeger]

Am 21.10.22 um 16:59 schrieb Jason J. Herne:
> 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")
> 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;


Thanks, will go via s390-fixes.

Alex, FYI.