UIE being set can cause maintenance interrupts to occur when Xen writes to one or more LR registers. The effect is a busy loop around the interrupt handler in Xen (http://marc.info/?l=xen-devel&m=141597517132682): everything gets stuck.
Konrad, this fixes an actual bug, at least on OMAP5. It should have no bad side effects on any other platforms as far as I can tell. It should go in 4.5. Signed-off-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com> Tested-by: Andrii Tseglytskyi <andrii.tseglyts...@globallogic.com> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c index 70d10d6..df140b9 100644 --- a/xen/arch/arm/gic.c +++ b/xen/arch/arm/gic.c @@ -403,6 +403,8 @@ void gic_clear_lrs(struct vcpu *v) if ( is_idle_vcpu(v) ) return; + gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); + spin_lock_irqsave(&v->arch.vgic.lock, flags); while ((i = find_next_bit((const unsigned long *) &this_cpu(lr_mask), @@ -527,8 +529,6 @@ void gic_inject(void) if ( !list_empty(¤t->arch.vgic.lr_pending) && lr_all_full() ) gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 1); - else - gic_hw_ops->update_hcr_status(GICH_HCR_UIE, 0); } static void do_sgi(struct cpu_user_regs *regs, enum gic_sgi sgi) _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel