| Message ID | 20210610202011.391029-1-farman@linux.ibm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | vfio-ccw: Fix garbage sense data on I/O error | expand |
On 6/10/21 4:20 PM, Eric Farman wrote: > Hi Conny, > > Per our offline discussion, here's a fix for the error when a guest > issues "dasdfmt -M quick". It basically reverts commit 334e76850bbb > ("vfio/ccw: update sense data if a unit check is pending") > and modifies the check that builds sense data in the TSCH handler. Should it includes a Fixes: tag then? > > I opted to NOT disable PMCW.CSENSE, because doing so prevents > vfio-ccw devices from coming online at all (didn't pursue deep > enough to explain why). Turning it off in reaction to a unit > check (in this now-reverted codepath) works, but only because of > the corresponding PMCW.CSENSE check in the TSCH code. > > I don't know if anything is needed for the (unaltered) ECW data > that commit b498484ed49a ("s390x/css: sense data endianness") > addressed for the copied sense_data bytes, but figure we can > use this as a starting point. Thoughts? > > Eric Farman (1): > vfio-ccw: Keep passthrough sense data intact > > hw/s390x/css.c | 3 ++- > hw/vfio/ccw.c | 6 ------ > 2 files changed, 2 insertions(+), 7 deletions(-) >
On Thu, 2021-06-10 at 16:25 -0400, Matthew Rosato wrote: > On 6/10/21 4:20 PM, Eric Farman wrote: > > Hi Conny, > > > > Per our offline discussion, here's a fix for the error when a guest > > issues "dasdfmt -M quick". It basically reverts commit 334e76850bbb > > ("vfio/ccw: update sense data if a unit check is pending") > > and modifies the check that builds sense data in the TSCH handler. > > Should it includes a Fixes: tag then? Yeah, probably. I'll fix it locally so it's prepped for a v2. > > > I opted to NOT disable PMCW.CSENSE, because doing so prevents > > vfio-ccw devices from coming online at all (didn't pursue deep > > enough to explain why). Turning it off in reaction to a unit > > check (in this now-reverted codepath) works, but only because of > > the corresponding PMCW.CSENSE check in the TSCH code. > > > > I don't know if anything is needed for the (unaltered) ECW data > > that commit b498484ed49a ("s390x/css: sense data endianness") > > addressed for the copied sense_data bytes, but figure we can > > use this as a starting point. Thoughts? > > > > Eric Farman (1): > > vfio-ccw: Keep passthrough sense data intact > > > > hw/s390x/css.c | 3 ++- > > hw/vfio/ccw.c | 6 ------ > > 2 files changed, 2 insertions(+), 7 deletions(-) > >
On Thu, Jun 10 2021, Eric Farman <farman@linux.ibm.com> wrote: > Hi Conny, > > Per our offline discussion, here's a fix for the error when a guest > issues "dasdfmt -M quick". It basically reverts commit 334e76850bbb > ("vfio/ccw: update sense data if a unit check is pending") > and modifies the check that builds sense data in the TSCH handler. > > I opted to NOT disable PMCW.CSENSE, because doing so prevents > vfio-ccw devices from coming online at all (didn't pursue deep > enough to explain why). Turning it off in reaction to a unit > check (in this now-reverted codepath) works, but only because of > the corresponding PMCW.CSENSE check in the TSCH code. It's a bit puzzling why fencing it off in msch doesn't work; but maybe it would not be the right thing to do anyway, if we can support some concurrent sense operations. I'm still reading the PoP. > > I don't know if anything is needed for the (unaltered) ECW data > that commit b498484ed49a ("s390x/css: sense data endianness") > addressed for the copied sense_data bytes, but figure we can > use this as a starting point. Thoughts? > > Eric Farman (1): > vfio-ccw: Keep passthrough sense data intact > > hw/s390x/css.c | 3 ++- > hw/vfio/ccw.c | 6 ------ > 2 files changed, 2 insertions(+), 7 deletions(-) >
Hi Conny, Per our offline discussion, here's a fix for the error when a guest issues "dasdfmt -M quick". It basically reverts commit 334e76850bbb ("vfio/ccw: update sense data if a unit check is pending") and modifies the check that builds sense data in the TSCH handler. I opted to NOT disable PMCW.CSENSE, because doing so prevents vfio-ccw devices from coming online at all (didn't pursue deep enough to explain why). Turning it off in reaction to a unit check (in this now-reverted codepath) works, but only because of the corresponding PMCW.CSENSE check in the TSCH code. I don't know if anything is needed for the (unaltered) ECW data that commit b498484ed49a ("s390x/css: sense data endianness") addressed for the copied sense_data bytes, but figure we can use this as a starting point. Thoughts? Eric Farman (1): vfio-ccw: Keep passthrough sense data intact hw/s390x/css.c | 3 ++- hw/vfio/ccw.c | 6 ------ 2 files changed, 2 insertions(+), 7 deletions(-)