diff options
| -rw-r--r-- | arch/x86/xen/events.c | 46 |
1 files changed, 30 insertions, 16 deletions
diff --git a/arch/x86/xen/events.c b/arch/x86/xen/events.c index f73b53bd65b7..85bac298b3cb 100644 --- a/arch/x86/xen/events.c +++ b/arch/x86/xen/events.c @@ -517,29 +517,43 @@ void xen_evtchn_do_upcall(struct pt_regs *regs) int cpu = get_cpu(); struct shared_info *s = HYPERVISOR_shared_info; struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu); - unsigned long pending_words; + static DEFINE_PER_CPU(unsigned, nesting_count); + unsigned count; - vcpu_info->evtchn_upcall_pending = 0; + do { + unsigned long pending_words; - /* NB. No need for a barrier here -- XCHG is a barrier on x86. */ - pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0); - while (pending_words != 0) { - unsigned long pending_bits; - int word_idx = __ffs(pending_words); - pending_words &= ~(1UL << word_idx); + vcpu_info->evtchn_upcall_pending = 0; - while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) { - int bit_idx = __ffs(pending_bits); - int port = (word_idx * BITS_PER_LONG) + bit_idx; - int irq = evtchn_to_irq[port]; + if (__get_cpu_var(nesting_count)++) + goto out; - if (irq != -1) { - regs->orig_ax = ~irq; - do_IRQ(regs); + /* NB. No need for a barrier here -- XCHG is a barrier on x86. */ + pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0); + while (pending_words != 0) { + unsigned long pending_bits; + int word_idx = __ffs(pending_words); + pending_words &= ~(1UL << word_idx); + + while ((pending_bits = active_evtchns(cpu, s, word_idx)) != 0) { + int bit_idx = __ffs(pending_bits); + int port = (word_idx * BITS_PER_LONG) + bit_idx; + int irq = evtchn_to_irq[port]; + + if (irq != -1) { + regs->orig_ax = ~irq; + do_IRQ(regs); + } } } - } + BUG_ON(!irqs_disabled()); + + count = __get_cpu_var(nesting_count); + __get_cpu_var(nesting_count) = 0; + } while(count != 1); + +out: put_cpu(); } |