virtio-ccw: fix build breakage on windows

event_notifier_get_fd() is not available on windows hosts. Fix this by
moving the calls to event_notifier_get_fd() to the kvm code.
Reported-by: NStefan Weil <sw@weilnetz.de>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NCornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/virtio-ccw.c

@@ -79,8 +79,7 @@ static int virtio_ccw_set_guest2host_notifier(VirtioCcwDevice *dev, int n,
             return r;
         }
         virtio_queue_set_host_notifier_fd_handler(vq, true, set_handler);
-        r = s390_assign_subch_ioeventfd(event_notifier_get_fd(notifier), sch_id,
-                                        n, assign);
+        r = s390_assign_subch_ioeventfd(notifier, sch_id, n, assign);
         if (r < 0) {
             error_report("%s: unable to assign ioeventfd: %d", __func__, r);
             virtio_queue_set_host_notifier_fd_handler(vq, false, false);
@@ -89,8 +88,7 @@ static int virtio_ccw_set_guest2host_notifier(VirtioCcwDevice *dev, int n,
         }
     } else {
         virtio_queue_set_host_notifier_fd_handler(vq, false, false);
-        s390_assign_subch_ioeventfd(event_notifier_get_fd(notifier), sch_id,
-                                    n, assign);
+        s390_assign_subch_ioeventfd(notifier, sch_id, n, assign);
         event_notifier_cleanup(notifier);
     }
     return r;

target-s390x/cpu.h

@@ -1081,7 +1081,8 @@ void kvm_s390_io_interrupt(S390CPU *cpu, uint16_t subchannel_id,
 void kvm_s390_crw_mchk(S390CPU *cpu);
 void kvm_s390_enable_css_support(S390CPU *cpu);
 int kvm_s390_get_registers_partial(CPUState *cpu);
-int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq, bool assign);
+int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
+                                    int vq, bool assign);
 #else
 static inline void kvm_s390_io_interrupt(S390CPU *cpu,
                                         uint16_t subchannel_id,
@@ -1100,7 +1101,8 @@ static inline int kvm_s390_get_registers_partial(CPUState *cpu)
 {
     return -ENOSYS;
 }
-static inline int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq,
+static inline int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier,
+                                                  uint32_t sch, int vq,
                                                   bool assign)
 {
     return -ENOSYS;
@@ -1131,11 +1133,12 @@ static inline void s390_crw_mchk(S390CPU *cpu)
     }
 }
 
-static inline int s390_assign_subch_ioeventfd(int fd, uint32_t sch_id, int vq,
+static inline int s390_assign_subch_ioeventfd(EventNotifier *notifier,
+                                              uint32_t sch_id, int vq,
                                               bool assign)
 {
     if (kvm_enabled()) {
-        return kvm_s390_assign_subch_ioeventfd(fd, sch_id, vq, assign);
+        return kvm_s390_assign_subch_ioeventfd(notifier, sch_id, vq, assign);
     } else {
         return -ENOSYS;
     }

target-s390x/kvm.c

@@ -934,12 +934,13 @@ void kvm_arch_init_irq_routing(KVMState *s)
 {
 }
 
-int kvm_s390_assign_subch_ioeventfd(int fd, uint32_t sch, int vq, bool assign)
+int kvm_s390_assign_subch_ioeventfd(EventNotifier *notifier, uint32_t sch,
+                                    int vq, bool assign)
 {
     struct kvm_ioeventfd kick = {
         .flags = KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY |
         KVM_IOEVENTFD_FLAG_DATAMATCH,
-        .fd = fd,
+        .fd = event_notifier_get_fd(notifier),
         .datamatch = vq,
         .addr = sch,
         .len = 8,