Re: [PATCH v7 06/15] s390/vfio-ap: sysfs attribute to display the guest CRYCB

From: Cornelia Huck <cohuck@redhat.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, freude@linux.ibm.com,
	borntraeger@de.ibm.com, mjrosato@linux.ibm.com,
	pmorel@linux.ibm.com, pasic@linux.ibm.com,
	alex.williamson@redhat.com, kwankhede@nvidia.com,
	jjherne@linux.ibm.com, fiuczy@linux.ibm.com
Subject: Re: [PATCH v7 06/15] s390/vfio-ap: sysfs attribute to display the guest CRYCB
Date: Wed, 8 Apr 2020 12:33:44 +0200	[thread overview]
Message-ID: <20200408123344.1a9032e1.cohuck@redhat.com> (raw)
In-Reply-To: <20200407192015.19887-7-akrowiak@linux.ibm.com>

On Tue,  7 Apr 2020 15:20:06 -0400
Tony Krowiak <akrowiak@linux.ibm.com> wrote:

> The matrix of adapters and domains configured in a guest's CRYCB may
> differ from the matrix of adapters and domains assigned to the matrix mdev,
> so this patch introduces a sysfs attribute to display the CRYCB of a guest
> using the matrix mdev. For a matrix mdev denoted by $uuid, the crycb for a
> guest using the matrix mdev can be displayed as follows:
> 
>    cat /sys/devices/vfio_ap/matrix/$uuid/guest_matrix
> 
> If a guest is not using the matrix mdev at the time the crycb is displayed,
> an error (ENODEV) will be returned.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>
> ---
>  drivers/s390/crypto/vfio_ap_ops.c | 58 +++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)

> +static DEVICE_ATTR_RO(guest_matrix);

Hm... should information like the guest configuration be readable by
everyone? Or should it be restricted a bit more?

> +
>  static struct attribute *vfio_ap_mdev_attrs[] = {
>  	&dev_attr_assign_adapter.attr,
>  	&dev_attr_unassign_adapter.attr,
> @@ -1050,6 +1107,7 @@ static struct attribute *vfio_ap_mdev_attrs[] = {
>  	&dev_attr_unassign_control_domain.attr,
>  	&dev_attr_control_domains.attr,
>  	&dev_attr_matrix.attr,
> +	&dev_attr_guest_matrix.attr,
>  	NULL,
>  };
>  