kvm-irqchip: i386: add hook for add/remove virq

Adding two hooks to be notified when adding/removing msi routes. There
are two kinds of MSI routes:

- in kvm_irqchip_add_irq_route(): before assigning IRQFD. Used by
  vhost, vfio, etc.

- in kvm_irqchip_send_msi(): when sending direct MSI message, if
  direct MSI not allowed, we will first create one MSI route entry
  in the kernel, then trigger it.

This patch only hooks the first one (irqfd case). We do not need to
take care for the 2nd one, since it's only used by QEMU userspace
(kvm-apic) and the messages will always do in-time translation when
triggered. While we need to note them down for the 1st one, so that we
can notify the kernel when cache invalidation happens.

Also, we do not hook IOAPIC msi routes (we have explicit notifier for
IOAPIC to keep its cache updated). We only need to care about irqfd
users.

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/target-s390x/kvm.c b/target-s390x/kvm.c
index 2991bff6a4..80ac6215fb 100644
--- a/target-s390x/kvm.c
+++ b/target-s390x/kvm.c
@@ -2267,6 +2267,17 @@ int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
     return 0;
 }
 
+int kvm_arch_add_msi_route_post(struct kvm_irq_routing_entry *route,
+                                int vector, PCIDevice *dev)
+{
+    return 0;
+}
+
+int kvm_arch_release_virq_post(int virq)
+{
+    return 0;
+}
+
 int kvm_arch_msi_data_to_gsi(uint32_t data)
 {
     abort();