KVM: Report IRQ injection status to userspace.

IRQ injection status is either -1 (if there was no CPU found
that should except the interrupt because IRQ was masked or
ioapic was misconfigured or ...) or >= 0 in that case the
number indicates to how many CPUs interrupt was injected.
If the value is 0 it means that the interrupt was coalesced
and probably should be reinjected.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

2 files changed, 8 insertions, 3 deletions

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 2163b3dd36e7..dd48225d1824 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -48,7 +48,10 @@ struct kvm_irq_level {
          * For IA-64 (APIC model) IOAPIC0: irq 0-23; IOAPIC1: irq 24-47..
          * For X86 (standard AT mode) PIC0/1: irq 0-15. IOAPIC0: 0-23..
          */
-        __u32 irq;
+        union {
+                __u32 irq;
+                __s32 status;
+        };
         __u32 level;
 };
 
@@ -402,6 +405,7 @@ struct kvm_trace_rec {
 #ifdef __KVM_HAVE_IOAPIC
 #define KVM_CAP_IRQ_ROUTING 25
 #endif
+#define KVM_CAP_IRQ_INJECT_STATUS 26
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -465,6 +469,7 @@ struct kvm_irq_routing {
 #define KVM_CREATE_PIT            _IO(KVMIO,  0x64)
 #define KVM_GET_PIT               _IOWR(KVMIO, 0x65, struct kvm_pit_state)
 #define KVM_SET_PIT               _IOR(KVMIO,  0x66, struct kvm_pit_state)
+#define KVM_IRQ_LINE_STATUS       _IOWR(KVMIO, 0x67, struct kvm_irq_level)
 #define KVM_REGISTER_COALESCED_MMIO \
                         _IOW(KVMIO,  0x67, struct kvm_coalesced_mmio_zone)
 #define KVM_UNREGISTER_COALESCED_MMIO \
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 18b4df8264cf..894a56e365e8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -110,7 +110,7 @@ struct kvm_memory_slot {
 
 struct kvm_kernel_irq_routing_entry {
         u32 gsi;
-        void (*set)(struct kvm_kernel_irq_routing_entry *e,
+        int (*set)(struct kvm_kernel_irq_routing_entry *e,
                     struct kvm *kvm, int level);
         union {
                 struct {
@@ -352,7 +352,7 @@ void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                                       struct kvm_irq_mask_notifier *kimn);
 void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask);
 
-void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
                                    struct kvm_irq_ack_notifier *kian);