On Fri, 2018-05-04 at 20:42 +1000, Michael Ellerman wrote:
> Cédric Le Goater <c...@kaod.org> writes:
>
> > This is not the case for the moment, but future releases of pHyp might
> > need to introduce some synchronisation routines under the hood which
> > would make the XIVE hcalls longer to complete.
> >
> > As this was done for H_INT_RESET, let's wrap the other hcalls in a
> > loop catching the H_LONG_BUSY_* codes.
>
> Are we sure it's safe to msleep() in all these paths?
Probably not. We can have the IRQ descriptor lock. We might need to
mdelay.
There's a Kconfig option (forgot which one) that will add checks for
attempts to sleep inside locks, you should run with that.
Cheers,
Ben.
>
> cheers
>
> > diff --git a/arch/powerpc/sysdev/xive/spapr.c
> > b/arch/powerpc/sysdev/xive/spapr.c
> > index 7113f5d87952..97ea0a67a173 100644
> > --- a/arch/powerpc/sysdev/xive/spapr.c
> > +++ b/arch/powerpc/sysdev/xive/spapr.c
> > @@ -165,7 +165,10 @@ static long plpar_int_get_source_info(unsigned long
> > flags,
> > unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
> > long rc;
> >
> > - rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
> > + do {
> > + rc = plpar_hcall(H_INT_GET_SOURCE_INFO, retbuf, flags, lisn);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_GET_SOURCE_INFO lisn=%ld failed %ld\n", lisn, rc);
> > return rc;
> > @@ -198,8 +201,11 @@ static long plpar_int_set_source_config(unsigned long
> > flags,
> > flags, lisn, target, prio, sw_irq);
> >
> >
> > - rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
> > - target, prio, sw_irq);
> > + do {
> > + rc = plpar_hcall_norets(H_INT_SET_SOURCE_CONFIG, flags, lisn,
> > + target, prio, sw_irq);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_SET_SOURCE_CONFIG lisn=%ld target=%lx prio=%lx
> > failed %ld\n",
> > lisn, target, prio, rc);
> > @@ -218,7 +224,11 @@ static long plpar_int_get_queue_info(unsigned long
> > flags,
> > unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
> > long rc;
> >
> > - rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target, priority);
> > + do {
> > + rc = plpar_hcall(H_INT_GET_QUEUE_INFO, retbuf, flags, target,
> > + priority);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_GET_QUEUE_INFO cpu=%ld prio=%ld failed %ld\n",
> > target, priority, rc);
> > @@ -247,8 +257,11 @@ static long plpar_int_set_queue_config(unsigned long
> > flags,
> > pr_devel("H_INT_SET_QUEUE_CONFIG flags=%lx target=%lx priority=%lx
> > qpage=%lx qsize=%lx\n",
> > flags, target, priority, qpage, qsize);
> >
> > - rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
> > - priority, qpage, qsize);
> > + do {
> > + rc = plpar_hcall_norets(H_INT_SET_QUEUE_CONFIG, flags, target,
> > + priority, qpage, qsize);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_SET_QUEUE_CONFIG cpu=%ld prio=%ld qpage=%lx
> > returned %ld\n",
> > target, priority, qpage, rc);
> > @@ -262,7 +275,10 @@ static long plpar_int_sync(unsigned long flags,
> > unsigned long lisn)
> > {
> > long rc;
> >
> > - rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
> > + do {
> > + rc = plpar_hcall_norets(H_INT_SYNC, flags, lisn);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_SYNC lisn=%ld returned %ld\n", lisn, rc);
> > return rc;
> > @@ -285,7 +301,11 @@ static long plpar_int_esb(unsigned long flags,
> > pr_devel("H_INT_ESB flags=%lx lisn=%lx offset=%lx in=%lx\n",
> > flags, lisn, offset, in_data);
> >
> > - rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset, in_data);
> > + do {
> > + rc = plpar_hcall(H_INT_ESB, retbuf, flags, lisn, offset,
> > + in_data);
> > + } while (plpar_busy_delay(rc));
> > +
> > if (rc) {
> > pr_err("H_INT_ESB lisn=%ld offset=%ld returned %ld\n",
> > lisn, offset, rc);
> > --
> > 2.13.6
