From e1d0b37261e6b7db18ebef6f1815489309312906 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Fri, 29 Mar 2019 11:11:01 +0000 Subject: [PATCH] hw/vfio/ccw: avoid taking address members in packed structs MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Message-Id: <20190329111104.17223-12-berrange@redhat.com> Reviewed-by: Eric Farman Reviewed-by: Halil Pasic Reviewed-by: Farhan Ali Signed-off-by: Cornelia Huck --- hw/vfio/ccw.c | 42 ++++++++++++++++++++++-------------------- 1 file changed, 22 insertions(+), 20 deletions(-) diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 9246729a75..c44d13cc50 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -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)); } -- 2.11.4.GIT