把虚拟机的通知写直接转成 eventfd 信号

766/* MMIO/PIO writes trigger an event if the addr/val match */767static int768ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,769		int len, const void *val)770{771	struct _ioeventfd *p = to_ioeventfd(this);772773	if (!ioeventfd_in_range(p, addr, len, val))774		return -EOPNOTSUPP;775776	eventfd_signal(p->eventfd);777	return 0;778}

721static bool722ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)723{724	u64 _val;725726	if (addr != p->addr)727		/* address must be precise for a hit */728		return false;729730	if (!p->length)731		/* length = 0 means only look at the address, so always a hit */732		return true;733734	if (len != p->length)735		/* address-range must be precise for a hit */736		return false;737738	if (p->wildcard)739		/* all else equal, wildcard is always a hit */740		return true;

335    bool modern_pio = proxy->flags & VIRTIO_PCI_FLAG_MODERN_PIO_NOTIFY;336    MemoryRegion *modern_mr = &proxy->notify.mr;337    MemoryRegion *modern_notify_mr = &proxy->notify_pio.mr;338    MemoryRegion *legacy_mr = &proxy->bar;339    hwaddr modern_addr = virtio_pci_queue_mem_mult(proxy) *340                         virtio_get_queue_index(vq);341    hwaddr legacy_addr = VIRTIO_PCI_QUEUE_NOTIFY;342343    if (assign) {344        if (modern) {345            memory_region_add_eventfd(modern_mr, modern_addr, 0,346                                      false, n, notifier);347            if (modern_pio) {348                memory_region_add_eventfd(modern_notify_mr, 0, 2,349                                              true, n, notifier);350            }351        }352        if (legacy) {353            memory_region_add_eventfd(legacy_mr, legacy_addr, 2,354                                      true, n, notifier);355        }