* [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error
@ 2021-06-10 20:20 Eric Farman
2021-06-10 20:20 ` [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact Eric Farman
` (2 more replies)
0 siblings, 3 replies; 9+ messages in thread
From: Eric Farman @ 2021-06-10 20:20 UTC (permalink / raw)
To: Cornelia Huck, qemu-devel, qemu-s390x
Cc: Thomas Huth, Matthew Rosato, David Hildenbrand,
Richard Henderson, Eric Farman, Halil Pasic,
Christian Borntraeger, Alex Williamson
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(-)
--
2.25.1
^ permalink raw reply [flat|nested] 9+ messages in thread* [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact 2021-06-10 20:20 [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Eric Farman @ 2021-06-10 20:20 ` Eric Farman 2021-06-11 7:15 ` Cornelia Huck 2021-06-10 20:25 ` [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Matthew Rosato 2021-06-11 7:12 ` Cornelia Huck 2 siblings, 1 reply; 9+ messages in thread From: Eric Farman @ 2021-06-10 20:20 UTC (permalink / raw) To: Cornelia Huck, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Eric Farman, Halil Pasic, Christian Borntraeger, Alex Williamson For virtual devices, there is space for sense data to be built and later copied into the IRB's ECW space once a TSCH is handled. For passthrough devices, the IRB is passed up from hardware. There might already be sense data in the ECW, in which case it would be unusual to overwrite the IRB ESW/ECW data with itself. In either case, if there isn't sense data, then an explicit SENSE operation might be needed from the guest driver. Regardless, fabricating sense data out of zeros seems like it would result in unexpected behavior. Let's remove the copying of the ECW/sense data in the vfio-ccw driver, and adapt the check in the TSCH handler to look for non-zero data in the local sense data before building a sense data response in the IRB. This fixes a "dasdfmt -M quick" command issued within a guest. Signed-off-by: Eric Farman <farman@linux.ibm.com> --- hw/s390x/css.c | 3 ++- hw/vfio/ccw.c | 6 ------ 2 files changed, 2 insertions(+), 7 deletions(-) diff --git a/hw/s390x/css.c b/hw/s390x/css.c index bed46f5ec3..29234daa27 100644 --- a/hw/s390x/css.c +++ b/hw/s390x/css.c @@ -1661,7 +1661,8 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len) } /* If a unit check is pending, copy sense data. */ if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { + (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) && + (sch->sense_data[0] != 0)) { int i; irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL; diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 139a3d9d1b..a4dc4acb34 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -371,12 +371,6 @@ static void vfio_ccw_io_notifier_handler(void *opaque) copy_scsw_to_guest(&s, &irb.scsw); schib->scsw = s; - /* If a uint check is pending, copy sense data. */ - if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { - memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw)); - } - read_err: css_inject_io_interrupt(sch); } -- 2.25.1 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact 2021-06-10 20:20 ` [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact Eric Farman @ 2021-06-11 7:15 ` Cornelia Huck 2021-06-11 10:21 ` Cornelia Huck 0 siblings, 1 reply; 9+ messages in thread From: Cornelia Huck @ 2021-06-11 7:15 UTC (permalink / raw) To: Eric Farman, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Eric Farman, Halil Pasic, Christian Borntraeger, Alex Williamson On Thu, Jun 10 2021, Eric Farman <farman@linux.ibm.com> wrote: > For virtual devices, there is space for sense data to be built > and later copied into the IRB's ECW space once a TSCH is handled. > > For passthrough devices, the IRB is passed up from hardware. > There might already be sense data in the ECW, in which case it > would be unusual to overwrite the IRB ESW/ECW data with itself. > > In either case, if there isn't sense data, then an explicit SENSE > operation might be needed from the guest driver. Regardless, > fabricating sense data out of zeros seems like it would result > in unexpected behavior. > > Let's remove the copying of the ECW/sense data in the vfio-ccw > driver, and adapt the check in the TSCH handler to look for > non-zero data in the local sense data before building a sense > data response in the IRB. > > This fixes a "dasdfmt -M quick" command issued within a guest. > > Signed-off-by: Eric Farman <farman@linux.ibm.com> > --- > hw/s390x/css.c | 3 ++- > hw/vfio/ccw.c | 6 ------ > 2 files changed, 2 insertions(+), 7 deletions(-) > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > index bed46f5ec3..29234daa27 100644 > --- a/hw/s390x/css.c > +++ b/hw/s390x/css.c > @@ -1661,7 +1661,8 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len) > } > /* If a unit check is pending, copy sense data. */ > if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { > + (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) && > + (sch->sense_data[0] != 0)) { > int i; > > irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | SCSW_FLAGS_MASK_ECTL; > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c > index 139a3d9d1b..a4dc4acb34 100644 > --- a/hw/vfio/ccw.c > +++ b/hw/vfio/ccw.c > @@ -371,12 +371,6 @@ static void vfio_ccw_io_notifier_handler(void *opaque) > copy_scsw_to_guest(&s, &irb.scsw); > schib->scsw = s; > > - /* If a uint check is pending, copy sense data. */ > - if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { If I'm reading the PoP correctly, turning on concurrent sense only means that we may have sense data already available, but not that it's guaranteed. Would it be enough to look at the relevant bit in the erw and only copy sense data if it is actually set (here and/or above)? > - memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw)); > - } > - > read_err: > css_inject_io_interrupt(sch); > } ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact 2021-06-11 7:15 ` Cornelia Huck @ 2021-06-11 10:21 ` Cornelia Huck 2021-06-11 12:51 ` Eric Farman 0 siblings, 1 reply; 9+ messages in thread From: Cornelia Huck @ 2021-06-11 10:21 UTC (permalink / raw) To: Eric Farman, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Eric Farman, Halil Pasic, Christian Borntraeger, Alex Williamson On Fri, Jun 11 2021, Cornelia Huck <cohuck@redhat.com> wrote: > On Thu, Jun 10 2021, Eric Farman <farman@linux.ibm.com> wrote: >> diff --git a/hw/s390x/css.c b/hw/s390x/css.c >> index bed46f5ec3..29234daa27 100644 >> --- a/hw/s390x/css.c >> +++ b/hw/s390x/css.c >> @@ -1661,7 +1661,8 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB *target_irb, int *irb_len) >> } >> /* If a unit check is pending, copy sense data. */ >> if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && >> - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { >> + (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) && >> + (sch->sense_data[0] != 0)) { >> int i; >> >> irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | >> SCSW_FLAGS_MASK_ECTL; This function is where we build the esw/ecw... >> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c >> index 139a3d9d1b..a4dc4acb34 100644 >> --- a/hw/vfio/ccw.c >> +++ b/hw/vfio/ccw.c >> @@ -371,12 +371,6 @@ static void vfio_ccw_io_notifier_handler(void *opaque) >> copy_scsw_to_guest(&s, &irb.scsw); >> schib->scsw = s; >> >> - /* If a uint check is pending, copy sense data. */ >> - if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && >> - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { ...and here we actually do have the esw/ecw provided by the hardware. > > If I'm reading the PoP correctly, turning on concurrent sense only means > that we may have sense data already available, but not that it's > guaranteed. Would it be enough to look at the relevant bit in the erw > and only copy sense data if it is actually set (here and/or above)? Maybe the root of the problem is that we actually try to build the esw ourselves? If we copy it from the irb received by the hardware, we should already have the correct data, I think. > >> - memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw)); >> - } >> - >> read_err: >> css_inject_io_interrupt(sch); >> } ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact 2021-06-11 10:21 ` Cornelia Huck @ 2021-06-11 12:51 ` Eric Farman 2021-06-11 14:37 ` Cornelia Huck 0 siblings, 1 reply; 9+ messages in thread From: Eric Farman @ 2021-06-11 12:51 UTC (permalink / raw) To: Cornelia Huck, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Halil Pasic, Christian Borntraeger, Alex Williamson On Fri, 2021-06-11 at 12:21 +0200, Cornelia Huck wrote: > On Fri, Jun 11 2021, Cornelia Huck <cohuck@redhat.com> wrote: > > > On Thu, Jun 10 2021, Eric Farman <farman@linux.ibm.com> wrote: > > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c > > > index bed46f5ec3..29234daa27 100644 > > > --- a/hw/s390x/css.c > > > +++ b/hw/s390x/css.c > > > @@ -1661,7 +1661,8 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB > > > *target_irb, int *irb_len) > > > } > > > /* If a unit check is pending, copy sense data. */ > > > if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && > > > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { > > > + (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) && > > > + (sch->sense_data[0] != 0)) { > > > int i; > > > > > > irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | > > > SCSW_FLAGS_MASK_ECTL; > > This function is where we build the esw/ecw... > > > > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c > > > index 139a3d9d1b..a4dc4acb34 100644 > > > --- a/hw/vfio/ccw.c > > > +++ b/hw/vfio/ccw.c > > > @@ -371,12 +371,6 @@ static void > > > vfio_ccw_io_notifier_handler(void *opaque) > > > copy_scsw_to_guest(&s, &irb.scsw); > > > schib->scsw = s; > > > > > > - /* If a uint check is pending, copy sense data. */ > > > - if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && > > > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { > > ...and here we actually do have the esw/ecw provided by the hardware. > > > If I'm reading the PoP correctly, turning on concurrent sense only > > means > > that we may have sense data already available, but not that it's > > guaranteed. Agreed. > > Would it be enough to look at the relevant bit in the erw > > and only copy sense data if it is actually set (here and/or above)? Do we have the hardware ERW in the css_do_tsch routine? Oh, but we have SCSW, and POPS says if ERW.S is set, SCSW.E is set. So that would make this a pretty simple change then. > > Maybe the root of the problem is that we actually try to build the > esw > ourselves? If we copy it from the irb received by the hardware, we > should already have the correct data, I think. Yeah, that's part of the problem. As you note above, the PMCW.CSENSE bit only says if concurrent sense is possible, not that it was actually stored in the IRB. I (mistakenly) thought that removing this hunk would get the whole IRB copied over, but I see now that css_do_tsch_get_irb() only copies the SCSW, and builds the ESW/ECW based off sch->sense_data. > > > > - memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw)); > > > - } > > > - > > > read_err: > > > css_inject_io_interrupt(sch); > > > } ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact 2021-06-11 12:51 ` Eric Farman @ 2021-06-11 14:37 ` Cornelia Huck 0 siblings, 0 replies; 9+ messages in thread From: Cornelia Huck @ 2021-06-11 14:37 UTC (permalink / raw) To: Eric Farman, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Halil Pasic, Christian Borntraeger, Alex Williamson On Fri, Jun 11 2021, Eric Farman <farman@linux.ibm.com> wrote: > On Fri, 2021-06-11 at 12:21 +0200, Cornelia Huck wrote: >> On Fri, Jun 11 2021, Cornelia Huck <cohuck@redhat.com> wrote: >> >> > On Thu, Jun 10 2021, Eric Farman <farman@linux.ibm.com> wrote: >> > > diff --git a/hw/s390x/css.c b/hw/s390x/css.c >> > > index bed46f5ec3..29234daa27 100644 >> > > --- a/hw/s390x/css.c >> > > +++ b/hw/s390x/css.c >> > > @@ -1661,7 +1661,8 @@ int css_do_tsch_get_irb(SubchDev *sch, IRB >> > > *target_irb, int *irb_len) >> > > } >> > > /* If a unit check is pending, copy sense data. */ >> > > if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && >> > > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { >> > > + (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE) && >> > > + (sch->sense_data[0] != 0)) { >> > > int i; >> > > >> > > irb.scsw.flags |= SCSW_FLAGS_MASK_ESWF | >> > > SCSW_FLAGS_MASK_ECTL; >> >> This function is where we build the esw/ecw... >> >> > > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c >> > > index 139a3d9d1b..a4dc4acb34 100644 >> > > --- a/hw/vfio/ccw.c >> > > +++ b/hw/vfio/ccw.c >> > > @@ -371,12 +371,6 @@ static void >> > > vfio_ccw_io_notifier_handler(void *opaque) >> > > copy_scsw_to_guest(&s, &irb.scsw); >> > > schib->scsw = s; >> > > >> > > - /* If a uint check is pending, copy sense data. */ >> > > - if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) && >> > > - (schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) { >> >> ...and here we actually do have the esw/ecw provided by the hardware. >> >> > If I'm reading the PoP correctly, turning on concurrent sense only >> > means >> > that we may have sense data already available, but not that it's >> > guaranteed. > > Agreed. > >> > Would it be enough to look at the relevant bit in the erw >> > and only copy sense data if it is actually set (here and/or above)? > > Do we have the hardware ERW in the css_do_tsch routine? > > Oh, but we have SCSW, and POPS says if ERW.S is set, SCSW.E is set. So > that would make this a pretty simple change then. Nod, that looks good. > >> >> Maybe the root of the problem is that we actually try to build the >> esw >> ourselves? If we copy it from the irb received by the hardware, we >> should already have the correct data, I think. > > Yeah, that's part of the problem. As you note above, the PMCW.CSENSE > bit only says if concurrent sense is possible, not that it was actually > stored in the IRB. > > I (mistakenly) thought that removing this hunk would get the whole IRB > copied over, but I see now that css_do_tsch_get_irb() only copies the > SCSW, and builds the ESW/ECW based off sch->sense_data. Might be a good idea to go over what we pass through vs. what we emulate for vfio-ccw devices, in case we have more conditions like this. We probably should not overwrite information that we can just move guestward. > >> >> > > - memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw)); >> > > - } >> > > - >> > > read_err: >> > > css_inject_io_interrupt(sch); >> > > } ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error 2021-06-10 20:20 [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Eric Farman 2021-06-10 20:20 ` [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact Eric Farman @ 2021-06-10 20:25 ` Matthew Rosato 2021-06-10 20:38 ` Eric Farman 2021-06-11 7:12 ` Cornelia Huck 2 siblings, 1 reply; 9+ messages in thread From: Matthew Rosato @ 2021-06-10 20:25 UTC (permalink / raw) To: Eric Farman, Cornelia Huck, qemu-devel, qemu-s390x Cc: Thomas Huth, David Hildenbrand, Richard Henderson, Halil Pasic, Christian Borntraeger, Alex Williamson 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(-) > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error 2021-06-10 20:25 ` [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Matthew Rosato @ 2021-06-10 20:38 ` Eric Farman 0 siblings, 0 replies; 9+ messages in thread From: Eric Farman @ 2021-06-10 20:38 UTC (permalink / raw) To: Matthew Rosato, Cornelia Huck, qemu-devel, qemu-s390x Cc: Thomas Huth, David Hildenbrand, Richard Henderson, Halil Pasic, Christian Borntraeger, Alex Williamson 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(-) > > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error 2021-06-10 20:20 [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Eric Farman 2021-06-10 20:20 ` [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact Eric Farman 2021-06-10 20:25 ` [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Matthew Rosato @ 2021-06-11 7:12 ` Cornelia Huck 2 siblings, 0 replies; 9+ messages in thread From: Cornelia Huck @ 2021-06-11 7:12 UTC (permalink / raw) To: Eric Farman, qemu-devel, qemu-s390x Cc: Thomas Huth, Matthew Rosato, David Hildenbrand, Richard Henderson, Eric Farman, Halil Pasic, Christian Borntraeger, Alex Williamson 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(-) > ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-06-11 14:38 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-06-10 20:20 [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Eric Farman 2021-06-10 20:20 ` [PATCH 1/1] vfio-ccw: Keep passthrough sense data intact Eric Farman 2021-06-11 7:15 ` Cornelia Huck 2021-06-11 10:21 ` Cornelia Huck 2021-06-11 12:51 ` Eric Farman 2021-06-11 14:37 ` Cornelia Huck 2021-06-10 20:25 ` [PATCH 0/1] vfio-ccw: Fix garbage sense data on I/O error Matthew Rosato 2021-06-10 20:38 ` Eric Farman 2021-06-11 7:12 ` Cornelia Huck
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