linux-kernel - Re: [PATCH 1/2] s390/vfio-ap: unpin pages on gisc registration failure

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Date:   Wed, 13 Sep 2023 14:10:35 -0400
From:   Matthew Rosato <mjrosato@...ux.ibm.com>
To:     Tony Krowiak <akrowiak@...ux.ibm.com>, linux-s390@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     jjherne@...ux.ibm.com, pasic@...ux.ibm.com,
        alex.williamson@...hat.com, borntraeger@...ux.ibm.com,
        kwankhede@...dia.com, frankja@...ux.ibm.com,
        imbrenda@...ux.ibm.com, david@...hat.com, stable@...r.kernel.org
Subject: Re: [PATCH 1/2] s390/vfio-ap: unpin pages on gisc registration
 failure

On 9/13/23 9:06 AM, Tony Krowiak wrote:
> From: Anthony Krowiak <akrowiak@...ux.ibm.com>
> 
> In the vfio_ap_irq_enable function, after the page containing the
> notification indicator byte (NIB) is pinned, the function attempts
> to register the guest ISC. If registration fails, the function sets the
> status response code and returns without unpinning the page containing
> the NIB. In order to avoid a memory leak, the NIB should be unpinned before
> returning from the vfio_ap_irq_enable function.
> 
> Fixes: 783f0a3ccd79 ("s390/vfio-ap: add s390dbf logging to the vfio_ap_irq_enable function")
> 
> Signed-off-by: Janosch Frank <frankja@...ux.ibm.com>
> Signed-off-by: Anthony Krowiak <akrowiak@...ux.ibm.com>
> Cc: <stable@...r.kernel.org>

Oops, good find.

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

> ---
>  drivers/s390/crypto/vfio_ap_ops.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 4db538a55192..9cb28978c186 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -457,6 +457,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
>  		VFIO_AP_DBF_WARN("%s: gisc registration failed: nisc=%d, isc=%d, apqn=%#04x\n",
>  				 __func__, nisc, isc, q->apqn);
>  
> +		vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1);
>  		status.response_code = AP_RESPONSE_INVALID_GISA;
>  		return status;
>  	}