Re: [Qemu-devel] [PATCH 0/2] s390x: reset handling for ccw devices

[Halil Pasic]

On 05/07/2018 05:51 PM, Cornelia Huck wrote:
> On Friday, Thomas noticed some problems with 3270 devices. One result
> was "s390x/css: disabled subchannels cannot be status pending", but
> a reboot did not cure the previous broken status. Turns out that 3270
> devices are missing a reset handler.
>
> This series cleans up reset handling a bit and makes sure that the base
> ccw device class provides a subchannel reset handler. I'm currently
> not sure what we should do with vfio-ccw, so the behaviour there is
> left unchanged.

Had a look, and LGTM (will tag separately) modulo what follows here. I'm
a bit concerned about vfio-ccw not being made compliant to this new
he reset of CCWDeviceClass is taking care of resetting the subchannel data
structures. This feels like introducing a common abstraction
to me, but then some things bother me.

In particular the the pim, the lpm and the pam set in css_reset_sch
seems to suit only devices that use the virtual chp. That
is it ain't suits any CCWDevice instance.

Do you plan to tackle vfio-ccw reset?

> Cornelia Huck (2):
>    virtio-ccw: common reset handler
>    s390x/ccw: make sure all ccw devices are properly reset
>
>   hw/s390x/ccw-device.c |  8 ++++++++
>   hw/s390x/virtio-ccw.c | 20 ++++++--------------
>   hw/s390x/virtio-ccw.h |  1 +
>   3 files changed, 15 insertions(+), 14 deletions(-)