KVM: Introduce direct MSI message injection for in-kernel irqchips

Currently, MSI messages can only be injected to in-kernel irqchips by
defining a corresponding IRQ route for each message. This is not only
unhandy if the MSI messages are generated "on the fly" by user space,
IRQ routes are a limited resource that user space has to manage
carefully.

By providing a direct injection path, we can both avoid using up limited
resources and simplify the necessary steps for user land.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 186ffab0b9f0..6f343307d72b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -802,6 +802,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
                         unsigned flags);
 void kvm_free_irq_routing(struct kvm *kvm);
 
+int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi);
+
 #else
 
 static inline void kvm_free_irq_routing(struct kvm *kvm) {}