On Tue, 24 Mar 2020 18:04:30 +0100 Cornelia Huck <coh...@redhat.com> wrote:
> On Thu, 6 Feb 2020 22:45:03 +0100 > Eric Farman <far...@linux.ibm.com> wrote: > > > From: Farhan Ali <al...@linux.ibm.com> > > > > 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'. I believe this is not the only situation when vfio-ccw returns EIO, or? > > > > Signed-off-by: Farhan Ali <al...@linux.ibm.com> > > Signed-off-by: Eric Farman <far...@linux.ibm.com> > > --- > > > > Notes: > > v1->v2: [EF] > > - Add s-o-b > > - [Seems the discussion on v1 centered on the return code > > set in the kernel, rather than anything that needs to > > change here, unless I've missed something.] Does this need to change here? If the kernel is supposed to return ENODEV then this does not need to change. > > I've stared at this and at the kernel code for some time again; and I'm > not sure if "return -EIO == not operational" is even true. That said, > I'm not sure a unit check is the right response, either. The only thing > I'm sure about is that the kernel code needs some review of return > codes and some documentation... I could not agree more, this is semantically uapi and needs to be properly documented. With regards to "linux error codes: vs "ionist cc's" an where the mapping is different example: """ /** * cio_cancel_halt_clear - Cancel running I/O by performing cancel, halt * and clear ordinally if subchannel is valid. * @sch: subchannel on which to perform the cancel_halt_clear operation * @iretry: the number of the times remained to retry the next operation * * This should be called repeatedly since halt/clear are asynchronous * operations. We do one try with cio_cancel, three tries with cio_halt, * 255 tries with cio_clear. The caller should initialize @iretry with * the value 255 for its first call to this, and keep using the same * @iretry in the subsequent calls until it gets a non -EBUSY return. * * Returns 0 if device now idle, -ENODEV for device not operational, * -EBUSY if an interrupt is expected (either from halt/clear or from a * status pending), and -EIO if out of retries. */ int cio_cancel_halt_clear(struct subchannel *sch, int *iretry) """ Here -ENODEV is not operational. Regards, Halil > > > > > hw/vfio/ccw.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c > > index 50cc2ec75c..19144ecfc7 100644 > > --- a/hw/vfio/ccw.c > > +++ b/hw/vfio/ccw.c > > @@ -114,6 +114,7 @@ again: > > return IOINST_CC_BUSY; > > case -ENODEV: > > case -EACCES: > > + case -EIO: > > return IOINST_CC_NOT_OPERATIONAL; > > case -EFAULT: > > default: > >
