[PATCH v1 0/1] vfio-ccw: Fix interrupt handling for HALT/CLEAR

Eric Farman
2020-01-24T14:55:06Z

Conny,

As I mentioned offline, I have been encountering some problems while
testing the channel path code. By pure coincidence, I found some
really good clues that led me to this proposed fix. I moved this
commit to the head of my channel path v2 code, but think maybe it
should be sent by itself so it doesn't get lost in that noise.

Figure 16-6 in SA22-7832-12 (POPS) goes into great detail of the
contents of the irb.cpa based on the other bits in the IRB.
Both the existing code and this new patch treates the irb.cpa as
valid all the time, even though that table has many many entries
where the cpa contents are "unpredictable." Methinks that this
is partially how we got into this mess, so maybe I need to write
some smarter logic here anyway? Thoughts?

(Disclaimer1: I didn't go back and re-read the conversations
that were had for the commit I marked in the "Fixes:" tag,
but will just to make sure we didn't miss something.)

(Disclaimer2: This makes my torturing-of-the-chpids test run
quite nicely, but I didn't go back to try some of the other
cruel-and-unusual tests at my disposable to ensure this patch
doesn't cause any other regressions. That's on today's agenda.)

Eric Farman (1):
vfio-ccw: Don't free channel programs for unrelated interrupts

drivers/s390/cio/vfio_ccw_cp.c | 11 +++++++++--
drivers/s390/cio/vfio_ccw_cp.h | 2 +-
drivers/s390/cio/vfio_ccw_drv.c | 4 ++--
3 files changed, 12 insertions(+), 5 deletions(-)

--
2.17.1