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>

1 files changed, 11 insertions, 2 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 05d7be89b5eb..e4db5be7c953 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1019,6 +1019,7 @@ int kvm_dev_ioctl_check_extension(long ext)
         case KVM_CAP_MP_STATE:
         case KVM_CAP_SYNC_MMU:
         case KVM_CAP_REINJECT_CONTROL:
+        case KVM_CAP_IRQ_INJECT_STATUS:
                 r = 1;
                 break;
         case KVM_CAP_COALESCED_MMIO:
@@ -1877,6 +1878,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
         create_pit_unlock:
                 mutex_unlock(&kvm->lock);
                 break;
+        case KVM_IRQ_LINE_STATUS:
         case KVM_IRQ_LINE: {
                 struct kvm_irq_level irq_event;
 
@@ -1884,10 +1886,17 @@ long kvm_arch_vm_ioctl(struct file *filp,
                 if (copy_from_user(&irq_event, argp, sizeof irq_event))
                         goto out;
                 if (irqchip_in_kernel(kvm)) {
+                        __s32 status;
                         mutex_lock(&kvm->lock);
-                        kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
-                                    irq_event.irq, irq_event.level);
+                        status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
+                                        irq_event.irq, irq_event.level);
                         mutex_unlock(&kvm->lock);
+                        if (ioctl == KVM_IRQ_LINE_STATUS) {
+                                irq_event.status = status;
+                                if (copy_to_user(argp, &irq_event,
+                                                        sizeof irq_event))
+                                        goto out;
+                        }
                         r = 0;
                 }
                 break;