Re: [PATCH v10 08/26] s390: vfio-ap: sysfs interfaces to configure control domains

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 12 Sep 2018 15:42:58 -0400
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> From: Tony Krowiak <akrowiak@linux.ibm.com>
> 
> Provides the sysfs interfaces for:
> 
> 1. Assigning AP control domains to the mediated matrix device
> 
> 2. Unassigning AP control domains from a mediated matrix device
> 
> 3. Displaying the control domains assigned to a mediated matrix
>    device
> 
> The IDs of the AP control domains assigned to the mediated matrix
> device are stored in an AP domain mask (ADM). The bits in the ADM,
> from most significant to least significant bit, correspond to
> AP domain numbers 0 to 255. On some systems, the maximum allowable
> domain number may be less than 255 - depending upon the host's
> AP configuration - and assignment may be rejected if the input
> domain ID exceeds the limit.
> 
> When a control domain is assigned, the bit corresponding its domain
> ID will be set in the ADM. Likewise, when a domain is unassigned,
> the bit corresponding to its domain ID will be cleared in the ADM.
> 
> The relevant sysfs structures are:
> 
> /sys/devices/vfio_ap/matrix/
> ...... [mdev_supported_types]
> ......... [vfio_ap-passthrough]
> ............ [devices]
> ...............[$uuid]
> .................. assign_control_domain
> .................. unassign_control_domain
> 
> To assign a control domain to the $uuid mediated matrix device's
> ADM, write its domain number to the assign_control_domain file.
> To unassign a domain, write its domain number to the
> unassign_control_domain file. The domain number is specified
> using conventional semantics: If it begins with 0x the number
> will be parsed as a hexadecimal (case insensitive) number;
> if it begins with 0, it is parsed as an octal number;
> otherwise, it will be parsed as a decimal number.
> 
> For example, to assign control domain 173 (0xad) to the mediated
> matrix device $uuid:
> 
> 	echo 173 > assign_control_domain
> 
> 	or
> 
> 	echo 0255 > assign_control_domain
> 
> 	or
> 
> 	echo 0xad > assign_control_domain
> 
> To unassign control domain 173 (0xad):
> 
> 	echo 173 > unassign_control_domain
> 
> 	or
> 
> 	echo 0255 > unassign_control_domain
> 
> 	or
> 
> 	echo 0xad > unassign_control_domain
> 
> The assignment will be rejected if the APQI exceeds the maximum
> value for an AP domain:
>   * If the AP Extended Addressing (APXA) facility is installed,
>     the max value is 255
>   * Else the max value is 15
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
> Tested-by: Michael Mueller <mimu@linux.ibm.com>
> Tested-by: Farhan Ali <alifm@linux.ibm.com>
> Tested-by: Pierre Morel <pmorel@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c |  112 +++++++++++++++++++++++++++++++++++++
>  1 files changed, 112 insertions(+), 0 deletions(-)
> 

Reviewed-by: Cornelia Huck <cohuck@redhat.com>