On Tue, Aug 05, 2014 at 10:24:11AM +0100, Anup Patel wrote: > A hypervisor will typically mask the overflow interrupt before > forwarding it to Guest Linux hence we need to re-enable the overflow > interrupt after clearing it in Guest Linux. Also, this re-enabling > of overflow interrupt does not harm in non-virtualized scenarios. > > Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx> > Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx> > --- > arch/arm64/kernel/perf_event.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index 47dfb8b..19fb140 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -1076,6 +1076,14 @@ static irqreturn_t armv8pmu_handle_irq(int irq_num, void *dev) > if (!armv8pmu_counter_has_overflowed(pmovsr, idx)) > continue; > > + /* > + * If we are running under a hypervisor such as KVM then > + * hypervisor will mask the interrupt before forwarding > + * it to Guest Linux hence re-enable interrupt for the > + * overflowed counter. > + */ > + armv8pmu_enable_intens(idx); > + Really? This is a giant bodge in the guest to work around short-comings in the hypervisor. Why can't we fix this properly using something like Marc's irq forwarding code? Will -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
