Re: [PATCH v4 2/3] s390/vfio-ap: set status response code to 06 on gisc registration failure

From: Christian Borntraeger <borntraeger@linux.ibm.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>
Cc: jjherne@linux.ibm.com, pasic@linux.ibm.com,
	alex.williamson@redhat.com, kwankhede@nvidia.com,
	frankja@linux.ibm.com, imbrenda@linux.ibm.com, david@redhat.com,
	Harald Freudenberger <freude@linux.ibm.com>
Subject: Re: [PATCH v4 2/3] s390/vfio-ap: set status response code to 06 on gisc registration failure
Date: Fri, 1 Dec 2023 10:57:28 +0100	[thread overview]
Message-ID: <90817094-9feb-84e6-7dc9-9b997f054242@linux.ibm.com> (raw)
In-Reply-To: <20231129145404.263764-3-akrowiak@linux.ibm.com>


Am 29.11.23 um 15:54 schrieb Tony Krowiak:
> From: Anthony Krowiak <akrowiak@linux.ibm.com>
> 
> The interception handler for the PQAP(AQIC) command calls the
> kvm_s390_gisc_register function to register the guest ISC with the channel
> subsystem. If that call fails, the status response code 08 - indicating
> Invalid ZONE/GISA designation - is returned to the guest. This response
> code is not valid because setting the ZONE/GISA values is the
> responsibility of the hypervisor controlling the guest and there is nothing
> that can be done from the guest perspective to correct that problem.
> 
> The likelihood of GISC registration failure is nil and there is no status
> response code to indicate an invalid ISC value, so let's set the response
> code to 06 indicating 'Invalid address of AP-queue notification byte'.
> While this is not entirely accurate, it is better than setting a response
> code which makes no sense for the guest.
> 
> Signed-off-by: Anthony Krowiak <akrowiak@linux.ibm.com>
> Suggested-by: Halil Pasic <pasic@linux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>

Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>

should go via the s390 tree

> ---
>   drivers/s390/crypto/vfio_ap_ops.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 9cb28978c186..25d7ce2094f8 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -393,8 +393,8 @@ static int ensure_nib_shared(unsigned long addr, struct gmap *gmap)
>    * Register the guest ISC to GIB interface and retrieve the
>    * host ISC to issue the host side PQAP/AQIC
>    *
> - * Response.status may be set to AP_RESPONSE_INVALID_ADDRESS in case the
> - * vfio_pin_pages failed.
> + * status.response_code may be set to AP_RESPONSE_INVALID_ADDRESS in case the
> + * vfio_pin_pages or kvm_s390_gisc_register failed.
>    *
>    * Otherwise return the ap_queue_status returned by the ap_aqic(),
>    * all retry handling will be done by the guest.
> @@ -458,7 +458,7 @@ static struct ap_queue_status vfio_ap_irq_enable(struct vfio_ap_queue *q,
>   				 __func__, nisc, isc, q->apqn);
>   
>   		vfio_unpin_pages(&q->matrix_mdev->vdev, nib, 1);
> -		status.response_code = AP_RESPONSE_INVALID_GISA;
> +		status.response_code = AP_RESPONSE_INVALID_ADDRESS;
>   		return status;
>   	}
>