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Reply-To: pmorel@linux.ibm.com
Subject: Re: [PATCH v6 13/21] s390: vfio-ap: sysfs interface to view matrix
 mdev matrix
From:   Pierre Morel <pmorel@linux.ibm.com>
To:     Tony Krowiak <akrowiak@linux.vnet.ibm.com>,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     freude@de.ibm.com, schwidefsky@de.ibm.com,
        heiko.carstens@de.ibm.com, borntraeger@de.ibm.com,
        cohuck@redhat.com, kwankhede@nvidia.com,
        bjsdjshi@linux.vnet.ibm.com, pbonzini@redhat.com,
        alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com,
        alifm@linux.vnet.ibm.com, mjrosato@linux.vnet.ibm.com,
        jjherne@linux.vnet.ibm.com, thuth@redhat.com,
        pasic@linux.vnet.ibm.com, berrange@redhat.com,
        fiuczy@linux.vnet.ibm.com, buendgen@de.ibm.com,
        Tony Krowiak <akrowiak@linux.ibm.com>
References: <1530306683-7270-1-git-send-email-akrowiak@linux.vnet.ibm.com>
 <1530306683-7270-14-git-send-email-akrowiak@linux.vnet.ibm.com>
 <ef3d480b-29b3-d184-4fb2-14f88961d97d@linux.ibm.com>
Date:   Mon, 9 Jul 2018 16:38:58 +0200
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On 09/07/2018 14:20, Pierre Morel wrote:
> On 29/06/2018 23:11, Tony Krowiak wrote:
>> Provides a sysfs interface to view the AP matrix configured for the
>> mediated matrix device.
>>
>> The relevant sysfs structures are:
>>
>> /sys/devices/vfio_ap
>> ... [matrix]
>> ...... [mdev_supported_types]
>> ......... [vfio_ap-passthrough]
>> ............ [devices]
>> ...............[$uuid]
>> .................. matrix
>>
>> To view the matrix configured for the mediated matrix device,
>> print the matrix file:
>>
>>     cat matrix
>>
>> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
>> ---
>>   drivers/s390/crypto/vfio_ap_ops.c |   31 
>> +++++++++++++++++++++++++++++++
>>   1 files changed, 31 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/s390/crypto/vfio_ap_ops.c 
>> b/drivers/s390/crypto/vfio_ap_ops.c
>> index c8f31f3..bc7398d 100644
>> --- a/drivers/s390/crypto/vfio_ap_ops.c
>> +++ b/drivers/s390/crypto/vfio_ap_ops.c
>> @@ -697,6 +697,36 @@ static ssize_t control_domains_show(struct 
>> device *dev,
>>   }
>>   DEVICE_ATTR_RO(control_domains);
>>
>> +static ssize_t matrix_show(struct device *dev, struct 
>> device_attribute *attr,
>> +               char *buf)
>> +{
>> +    struct mdev_device *mdev = mdev_from_dev(dev);
>> +    struct ap_matrix_mdev *matrix_mdev = mdev_get_drvdata(mdev);
>> +    char *bufpos = buf;
>> +    unsigned long apid;
>> +    unsigned long apqi;
>> +    unsigned long napm = matrix_mdev->matrix.apm_max + 1;
>> +    unsigned long naqm = matrix_mdev->matrix.aqm_max + 1;
>> +    int nchars = 0;
>> +    int n;
>> +
>> +    for_each_set_bit_inv(apid, matrix_mdev->matrix.apm, napm) {
>> +        n = sprintf(bufpos, "%02lx\n", apid);
>> +        bufpos += n;
>> +        nchars += n;
>> +
>> +        for_each_set_bit_inv(apqi, matrix_mdev->matrix.aqm, naqm) {
>> +            n = sprintf(bufpos, "%02lx.%04lx\n", apid, apqi);
>> +            bufpos += n;
>> +            nchars += n;
>> +        }
>> +    }
>> +
>> +    return nchars;
>> +}
>> +DEVICE_ATTR_RO(matrix);
>> +
>> +
>>   static struct attribute *vfio_ap_mdev_attrs[] = {
>>       &dev_attr_assign_adapter.attr,
>>       &dev_attr_unassign_adapter.attr,
>> @@ -705,6 +735,7 @@ static ssize_t control_domains_show(struct device 
>> *dev,
>>       &dev_attr_assign_control_domain.attr,
>>       &dev_attr_unassign_control_domain.attr,
>>       &dev_attr_control_domains.attr,
>> +    &dev_attr_matrix.attr,
>>       NULL,
>>   };
>>
>
> I have still the same remark: what you show here is not what is currently
> used by the SIE.
> It is not irrelevant but what the guest really use may be more 
> interesting
> for the admin.
>
>
OK, you implement the right view it in patch 16/21.

Still, what is the purpose of showing this view?


-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany