static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq, int irq_level, bool line_status) { union kvm_ioapic_redirect_entry entry; u32 mask = 1 << irq; u32 old_irr; int edge, ret; entry = ioapic->redirtbl[irq]; edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG); if (!irq_level) { ioapic->irr &= ~mask; ret = 1; goto out; } /* * Return 0 for coalesced interrupts; for edge-triggered interrupts, * this only happens if a previous edge has not been delivered due * do masking. For level interrupts, the remote_irr field tells * us if the interrupt is waiting for an EOI. * * RTC is special: it is edge-triggered, but userspace likes to know * if it has been already ack-ed via EOI because coalesced RTC * interrupts lead to time drift in Windows guests. So we track * EOI manually for the RTC interrupt. */ if (irq == RTC_GSI && line_status && rtc_irq_check_coalesced(ioapic)) { ret = 0; goto out; } old_irr = ioapic->irr; ioapic->irr |= mask; if (edge) ioapic->irr_delivered &= ~mask; if ((edge && old_irr == ioapic->irr) || (!edge && entry.fields.remote_irr)) { ret = 0; goto out; } ret = ioapic_service(ioapic, irq, line_status); out: trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0); return ret; }
int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id, int level, bool line_status) { u32 old_irr; u32 mask = 1 << irq; union kvm_ioapic_redirect_entry entry; int ret, irq_level; BUG_ON(irq < 0 || irq >= IOAPIC_NUM_PINS); spin_lock(&ioapic->lock); old_irr = ioapic->irr; irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq], irq_source_id, level); entry = ioapic->redirtbl[irq]; irq_level ^= entry.fields.polarity; if (!irq_level) { ioapic->irr &= ~mask; ret = 1; } else { int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG); if (irq == RTC_GSI && line_status && rtc_irq_check_coalesced(ioapic)) { ret = 0; /* coalesced */ goto out; } ioapic->irr |= mask; if ((edge && old_irr != ioapic->irr) || (!edge && !entry.fields.remote_irr)) ret = ioapic_service(ioapic, irq, line_status); else ret = 0; /* report coalesced interrupt */ } out: trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0); spin_unlock(&ioapic->lock); return ret; }