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hw/vfio/ccw: avoid taking address members in packed structs 

The GCC 9 compiler complains about many places in s390 code
that take the address of members of the 'struct SCHIB' which
is marked packed:

hw/vfio/ccw.c: In function ‘vfio_ccw_io_notifier_handler’:
hw/vfio/ccw.c:133:15: warning: taking address of packed member of ‘struct SCHIB’ may result in an unaligned pointer value \
[-Waddress-of-packed-member]
  133 |     SCSW *s = &sch->curr_status.scsw;
      |               ^~~~~~~~~~~~~~~~~~~~~~
hw/vfio/ccw.c:134:15: warning: taking address of packed member of ‘struct SCHIB’ may result in an unaligned pointer value \
[-Waddress-of-packed-member]
  134 |     PMCW *p = &sch->curr_status.pmcw;
      |               ^~~~~~~~~~~~~~~~~~~~~~

...snip many more...

Almost all of these are just done for convenience to avoid
typing out long variable/field names when referencing struct
members. We can get most of this convenience by taking the
address of the 'struct SCHIB' instead, avoiding triggering
the compiler warnings.

In a couple of places we copy via a local variable which is
a technique already applied elsewhere in s390 code for this
problem.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20190329111104.17223-12-berrange@redhat.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Farhan Ali <alifm@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2019-03-29 11:11:01 +00:00 committed by Cornelia Huck
parent 061b51e919
commit e1d0b37261
1 changed files with 22 additions and 20 deletions
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42
hw/vfio/ccw.c
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@ -130,8 +130,8 @@ static void vfio_ccw_io_notifier_handler(void *opaque)
S390CCWDevice *cdev = S390_CCW_DEVICE(vcdev);
CcwDevice *ccw_dev = CCW_DEVICE(cdev);
SubchDev *sch = ccw_dev->sch;
SCSW *s = &sch->curr_status.scsw;
PMCW *p = &sch->curr_status.pmcw;
SCHIB *schib = &sch->curr_status;
SCSW s;
IRB irb;
int size;
@ -145,33 +145,33 @@ static void vfio_ccw_io_notifier_handler(void *opaque)
switch (errno) {
case ENODEV:
/* Generate a deferred cc 3 condition. */
s->flags |= SCSW_FLAGS_MASK_CC;
s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
s->ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);
schib->scsw.flags |= SCSW_FLAGS_MASK_CC;
schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
schib->scsw.ctrl |= (SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND);
goto read_err;
case EFAULT:
/* Memory problem, generate channel data check. */
s->ctrl &= ~SCSW_ACTL_START_PEND;
s->cstat = SCSW_CSTAT_DATA_CHECK;
s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
schib->scsw.cstat = SCSW_CSTAT_DATA_CHECK;
schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
goto read_err;
default:
/* Error, generate channel program check. */
s->ctrl &= ~SCSW_ACTL_START_PEND;
s->cstat = SCSW_CSTAT_PROG_CHECK;
s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
schib->scsw.cstat = SCSW_CSTAT_PROG_CHECK;
schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
goto read_err;
}
} else if (size != vcdev->io_region_size) {
/* Information transfer error, generate channel-control check. */
s->ctrl &= ~SCSW_ACTL_START_PEND;
s->cstat = SCSW_CSTAT_CHN_CTRL_CHK;
s->ctrl &= ~SCSW_CTRL_MASK_STCTL;
s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
schib->scsw.ctrl &= ~SCSW_ACTL_START_PEND;
schib->scsw.cstat = SCSW_CSTAT_CHN_CTRL_CHK;
schib->scsw.ctrl &= ~SCSW_CTRL_MASK_STCTL;
schib->scsw.ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY |
SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND;
goto read_err;
}
@ -179,11 +179,13 @@ static void vfio_ccw_io_notifier_handler(void *opaque)
memcpy(&irb, region->irb_area, sizeof(IRB));
/* Update control block via irb. */
copy_scsw_to_guest(s, &irb.scsw);
s = schib->scsw;
copy_scsw_to_guest(&s, &irb.scsw);
schib->scsw = s;
/* If a uint check is pending, copy sense data. */
if ((s->dstat & SCSW_DSTAT_UNIT_CHECK) &&
(p->chars & PMCW_CHARS_MASK_CSENSE)) {
if ((schib->scsw.dstat & SCSW_DSTAT_UNIT_CHECK) &&
(schib->pmcw.chars & PMCW_CHARS_MASK_CSENSE)) {
memcpy(sch->sense_data, irb.ecw, sizeof(irb.ecw));
}