| Message ID | 20210511195631.3995081-2-farman@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vfio-ccw: Fix interrupt handling for HALT/CLEAR | expand |
On 5/11/21 3:56 PM, Eric Farman wrote: > We have a really nice flag in the channel_program struct that > indicates if it had been initialized by cp_init(), and use it > as a guard in the other cp accessor routines, but not for a > duplicate call into cp_init(). The possibility of this occurring > is low, because that flow is protected by the private->io_mutex > and FSM CP_PROCESSING state. But then why bother checking it > in (for example) cp_prefetch() then? > > Let's just be consistent and check for that in cp_init() too. > > Fixes: 71189f263f8a3 ("vfio-ccw: make it safe to access channel programs") > Signed-off-by: Eric Farman <farman@linux.ibm.com> > Reviewed-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Matthew Rosato <mjrosato@linux.ibm.com> > --- > drivers/s390/cio/vfio_ccw_cp.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > index b9febc581b1f..8d1b2771c1aa 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -638,6 +638,10 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb) > static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1); > int ret; > > + /* this is an error in the caller */ > + if (cp->initialized) > + return -EBUSY; > + > /* > * We only support prefetching the channel program. We assume all channel > * programs executed by supported guests likewise support prefetching. >
diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index b9febc581b1f..8d1b2771c1aa 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -638,6 +638,10 @@ int cp_init(struct channel_program *cp, struct device *mdev, union orb *orb) static DEFINE_RATELIMIT_STATE(ratelimit_state, 5 * HZ, 1); int ret; + /* this is an error in the caller */ + if (cp->initialized) + return -EBUSY; + /* * We only support prefetching the channel program. We assume all channel * programs executed by supported guests likewise support prefetching.
We have a really nice flag in the channel_program struct that indicates if it had been initialized by cp_init(), and use it as a guard in the other cp accessor routines, but not for a duplicate call into cp_init(). The possibility of this occurring is low, because that flow is protected by the private->io_mutex and FSM CP_PROCESSING state. But then why bother checking it in (for example) cp_prefetch() then? Let's just be consistent and check for that in cp_init() too. Fixes: 71189f263f8a3 ("vfio-ccw: make it safe to access channel programs") Signed-off-by: Eric Farman <farman@linux.ibm.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> --- drivers/s390/cio/vfio_ccw_cp.c | 4 ++++ 1 file changed, 4 insertions(+)