| Message ID | 20191115033437.37926-3-farman@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | s390x/vfio-ccw: Channel Path Handling | expand |
On Fri, 15 Nov 2019 04:34:31 +0100 Eric Farman <farman@linux.ibm.com> wrote: > From: Farhan Ali <alifm@linux.ibm.com> > > According to PoPs, when the SCHIB.PMCW bit 8 is 0 status presented by > the device is not made available to the program. So don't inject an > interrupt in the guest if the guest OS has not enabled the > subchannel. Have you managed to trigger this state in real life? > > Signed-off-by: Farhan Ali <alifm@linux.ibm.com> > Signed-off-by: Eric Farman <farman@linux.ibm.com> > --- > > Notes: > v0->v1: [EF] > - Update commit message, as the bit in question is bit 8 not 15 > > hw/vfio/ccw.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c > index 0919ddbeb8..0590a6f512 100644 > --- a/hw/vfio/ccw.c > +++ b/hw/vfio/ccw.c > @@ -230,6 +230,11 @@ static void vfio_ccw_io_notifier_handler(void *opaque) > return; > } > > + /* Virtual subchannel is not enabled */ > + if (!(schib->pmcw.flags & PMCW_FLAGS_MASK_ENA)) { How can that happen? We should not be able to disable the subchannel while it is in active use, should we? I fear I'm missing something here... > + return; > + } > + > size = pread(vcdev->vdev.fd, region, vcdev->io_region_size, > vcdev->io_region_offset); > if (size == -1) {
On 11/18/19 1:23 PM, Cornelia Huck wrote: > On Fri, 15 Nov 2019 04:34:31 +0100 > Eric Farman <farman@linux.ibm.com> wrote: > >> From: Farhan Ali <alifm@linux.ibm.com> >> >> According to PoPs, when the SCHIB.PMCW bit 8 is 0 status presented by >> the device is not made available to the program. So don't inject an >> interrupt in the guest if the guest OS has not enabled the >> subchannel. > > Have you managed to trigger this state in real life? No, and I have no notes on how this came to be. I'll try running some of the config tests with this reverted, and see if I can find any weirdness. > >> >> Signed-off-by: Farhan Ali <alifm@linux.ibm.com> >> Signed-off-by: Eric Farman <farman@linux.ibm.com> >> --- >> >> Notes: >> v0->v1: [EF] >> - Update commit message, as the bit in question is bit 8 not 15 >> >> hw/vfio/ccw.c | 5 +++++ >> 1 file changed, 5 insertions(+) >> >> diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c >> index 0919ddbeb8..0590a6f512 100644 >> --- a/hw/vfio/ccw.c >> +++ b/hw/vfio/ccw.c >> @@ -230,6 +230,11 @@ static void vfio_ccw_io_notifier_handler(void *opaque) >> return; >> } >> >> + /* Virtual subchannel is not enabled */ >> + if (!(schib->pmcw.flags & PMCW_FLAGS_MASK_ENA)) { > > How can that happen? We should not be able to disable the subchannel > while it is in active use, should we? I fear I'm missing something > here... Me too... Hrm... > >> + return; >> + } >> + >> size = pread(vcdev->vdev.fd, region, vcdev->io_region_size, >> vcdev->io_region_offset); >> if (size == -1) { >
diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index 0919ddbeb8..0590a6f512 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -230,6 +230,11 @@ static void vfio_ccw_io_notifier_handler(void *opaque) return; } + /* Virtual subchannel is not enabled */ + if (!(schib->pmcw.flags & PMCW_FLAGS_MASK_ENA)) { + return; + } + size = pread(vcdev->vdev.fd, region, vcdev->io_region_size, vcdev->io_region_offset); if (size == -1) {