Re: [Qemu-devel] [PATCH v6 4/5] s390x/vfio: ap: Introduce VFIO AP device

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 29 Jun 2018 18:48:02 -0400
Tony Krowiak <akrowiak@linux.vnet.ibm.com> wrote:

> Introduces a VFIO based AP device. The device is defined via
> the QEMU command line by specifying:
> 
>     -device vfio-ap,sysfsdev=<path-to-mediated-matrix-device>
> 
> There may be only one vfio-ap device configured for a guest.
> 
> The mediated matrix device is created by the VFIO AP device
> driver by writing a UUID to a sysfs attribute file (see
> docs/vfio-ap.txt). The mediated matrix device will be named
> after the UUID. Symbolic links to the $uuid are created in
> many places, so the path to the mediated matrix device $uuid
> can be specified in any of the following ways:
> 
> /sys/devices/vfio_ap/matrix/$uuid
> /sys/devices/vfio_ap/matrix/mdev_supported_types/vfio_ap-passthrough/devices/$uuid
> /sys/bus/mdev/devices/$uuid
> /sys/bus/mdev/drivers/vfio_mdev/$uuid
> 
> When the vfio-ap device is realized, it acquires and opens the
> VFIO iommu group to which the mediated matrix device is
> bound. This causes a VFIO group notification event to be
> signaled. The vfio_ap device driver's group notification
> handler will get called at which time the device driver
> will configure the the AP devices to which the guest will
> be granted access.
> 
> Signed-off-by: Tony Krowiak <akrowiak@linux.vnet.ibm.com>
> Signed-off-by: Tony Krowiak <akrowiak@linux.ibm.com>

Nit: You may want to decide one address or the other :)

> ---
>  MAINTAINERS                       |    1 +
>  default-configs/s390x-softmmu.mak |    1 +
>  hw/vfio/Makefile.objs             |    1 +
>  hw/vfio/ap.c                      |  183 +++++++++++++++++++++++++++++++++++++
>  include/hw/vfio/vfio-common.h     |    1 +
>  5 files changed, 187 insertions(+), 0 deletions(-)
>  create mode 100644 hw/vfio/ap.c

No complaints about the code from me.