kvm: add KVM_IRQFD_FLAG_RESAMPLE support

Added an EventNotifier* parameter to
kvm-all.c:kvm_irqchip_add_irqfd_notifier(), in order to give KVM
another eventfd to be used as "resamplefd". See the documentation
in the linux kernel sources in Documentation/virtual/kvm/api.txt
(section 4.75) for more details.
When the added parameter is passed NULL, the behaviour of the
function is unchanged with respect to the previous versions.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Vincenzo Maffione <v.maffione@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 13 insertions, 4 deletions

diff --git a/kvm-all.c b/kvm-all.c
index 4fb4ccbeca..bfa4aac48e 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1230,7 +1230,8 @@ int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg)
     return kvm_update_routing_entry(s, &kroute);
 }
 
-static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int virq, bool assign)
+static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int rfd, int virq,
+                                    bool assign)
 {
     struct kvm_irqfd irqfd = {
         .fd = fd,
@@ -1238,6 +1239,11 @@ static int kvm_irqchip_assign_irqfd(KVMState *s, int fd, int virq, bool assign)
         .flags = assign ? 0 : KVM_IRQFD_FLAG_DEASSIGN,
     };
 
+    if (rfd != -1) {
+        irqfd.flags |= KVM_IRQFD_FLAG_RESAMPLE;
+        irqfd.resamplefd = rfd;
+    }
+
     if (!kvm_irqfds_enabled()) {
         return -ENOSYS;
     }
@@ -1276,14 +1282,17 @@ int kvm_irqchip_update_msi_route(KVMState *s, int virq, MSIMessage msg)
 }
 #endif /* !KVM_CAP_IRQ_ROUTING */
 
-int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n, int virq)
+int kvm_irqchip_add_irqfd_notifier(KVMState *s, EventNotifier *n,
+                                   EventNotifier *rn, int virq)
 {
-    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), virq, true);
+    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n),
+           rn ? event_notifier_get_fd(rn) : -1, virq, true);
 }
 
 int kvm_irqchip_remove_irqfd_notifier(KVMState *s, EventNotifier *n, int virq)
 {
-    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), virq, false);
+    return kvm_irqchip_assign_irqfd(s, event_notifier_get_fd(n), -1, virq,
+           false);
 }
 
 static int kvm_irqchip_create(KVMState *s)