| Message ID | 20170626163930.29697-1-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 26, 2017 at 06:39:30PM +0200, Vitaly Kuznetsov wrote: > CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests > BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a > leftover from ancient times when CPU0 hotplug was impossible, it works > just fine for HVM. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Perhaps: BUG_ON(cpu == 0 && xen_pv_domain()); ? > --- > - CPU0 hotplug is currently broken on x86, see > https://lkml.org/lkml/2017/6/26/529 > --- > arch/x86/xen/time.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c > index a1895a8..1ecb05d 100644 > --- a/arch/x86/xen/time.c > +++ b/arch/x86/xen/time.c > @@ -309,7 +309,6 @@ static irqreturn_t xen_timer_interrupt(int irq, void *dev_id) > void xen_teardown_timer(int cpu) > { > struct clock_event_device *evt; > - BUG_ON(cpu == 0); > evt = &per_cpu(xen_clock_events, cpu).evt; > > if (evt->irq >= 0) { > -- > 2.9.4 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > https://lists.xen.org/xen-devel
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> writes: > On Mon, Jun 26, 2017 at 06:39:30PM +0200, Vitaly Kuznetsov wrote: >> CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests >> BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a >> leftover from ancient times when CPU0 hotplug was impossible, it works >> just fine for HVM. >> >> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > > Perhaps: > > BUG_ON(cpu == 0 && xen_pv_domain()); > Linus says no BUG_ONs :-) xen_pv_cpu_disable() has the following: if (cpu == 0) return -EBUSY; as a protection so we won't get to xen_teardown_timer() but if you think additional BUG_ON() protection is justified I'm definitely not against adding it.
On 06/28/2017 06:31 PM, Vitaly Kuznetsov wrote: > Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> writes: > >> On Mon, Jun 26, 2017 at 06:39:30PM +0200, Vitaly Kuznetsov wrote: >>> CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests >>> BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a >>> leftover from ancient times when CPU0 hotplug was impossible, it works >>> just fine for HVM. >>> >>> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> >> >> Perhaps: >> >> BUG_ON(cpu == 0 && xen_pv_domain()); >> > > Linus says no BUG_ONs :-) > > xen_pv_cpu_disable() has the following: > > if (cpu == 0) > return -EBUSY; > > as a protection so we won't get to xen_teardown_timer() but if you think > additional BUG_ON() protection is justified I'm definitely not against > adding it. No, I don't think its needed. This should be handled at the appropriate level, not down in the timer handling. So: Acked-by: Juergen Gross <jgross@suse.com> Juergen
On 26/06/17 18:39, Vitaly Kuznetsov wrote: > CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests > BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a > leftover from ancient times when CPU0 hotplug was impossible, it works > just fine for HVM. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Committed to xen/tip for-linus-4.13 Thanks, Juergen
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index a1895a8..1ecb05d 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -309,7 +309,6 @@ static irqreturn_t xen_timer_interrupt(int irq, void *dev_id) void xen_teardown_timer(int cpu) { struct clock_event_device *evt; - BUG_ON(cpu == 0); evt = &per_cpu(xen_clock_events, cpu).evt; if (evt->irq >= 0) {
CONFIG_BOOTPARAM_HOTPLUG_CPU0 allows to offline CPU0 but Xen HVM guests BUG() in xen_teardown_timer(). Remove the BUG_ON(), this is probably a leftover from ancient times when CPU0 hotplug was impossible, it works just fine for HVM. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- - CPU0 hotplug is currently broken on x86, see https://lkml.org/lkml/2017/6/26/529 --- arch/x86/xen/time.c | 1 - 1 file changed, 1 deletion(-)