Re: [RFC PATCH v1 1/8] vfio-ccw: Return IOINST_CC_NOT_OPERATIONAL for EIO

[Halil Pasic]

On Mon, 18 Nov 2019 19:13:34 +0100
Cornelia Huck <address@hidden> wrote:

> > EIO is returned by vfio-ccw mediated device when the backing
> > host subchannel is not operational anymore. So return cc=3
> > back to the guest, rather than returning a unit check.
> > This way the guest can take appropriate action such as
> > issue an 'stsch'.  
> 
> Hnm, I'm trying to recall whether that was actually a conscious choice,
> but I can't quite remember... the change does make sense at a glance,
> however.

Is EIO returned if and only if the host subchannel/device is not
operational any more, or are there cases as well? Is the mapping
(cc to condition) documented? By the QEMU code I would think that
we already have ENODEV and EACCESS for 'not operational' -- no idea
why we need two codes though.

Regards,
Halil