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, 16 insertions, 7 deletions

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 1c986ac59ad6..c3b99def9cbc 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -83,19 +83,22 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
         return result;
 }
 
-static void ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
+static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 {
         union ioapic_redir_entry *pent;
+        int injected = -1;
 
         pent = &ioapic->redirtbl[idx];
 
         if (!pent->fields.mask) {
-                int injected = ioapic_deliver(ioapic, idx);
+                injected = ioapic_deliver(ioapic, idx);
                 if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
                         pent->fields.remote_irr = 1;
         }
         if (!pent->fields.trig_mode)
                 ioapic->irr &= ~(1 << idx);
+
+        return injected;
 }
 
 static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
@@ -207,7 +210,7 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
         u8 trig_mode = ioapic->redirtbl[irq].fields.trig_mode;
         u32 deliver_bitmask;
         struct kvm_vcpu *vcpu;
-        int vcpu_id, r = 0;
+        int vcpu_id, r = -1;
 
         ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
                      "vector=%x trig_mode=%x\n",
@@ -247,7 +250,9 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
                         deliver_bitmask &= ~(1 << vcpu_id);
                         vcpu = ioapic->kvm->vcpus[vcpu_id];
                         if (vcpu) {
-                                r = ioapic_inj_irq(ioapic, vcpu, vector,
+                                if (r < 0)
+                                        r = 0;
+                                r += ioapic_inj_irq(ioapic, vcpu, vector,
                                                trig_mode, delivery_mode);
                         }
                 }
@@ -258,8 +263,10 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
                                 continue;
                         deliver_bitmask &= ~(1 << vcpu_id);
                         vcpu = ioapic->kvm->vcpus[vcpu_id];
-                        if (vcpu)
+                        if (vcpu) {
                                 ioapic_inj_nmi(vcpu);
+                                r = 1;
+                        }
                         else
                                 ioapic_debug("NMI to vcpu %d failed\n",
                                                 vcpu->vcpu_id);
@@ -273,11 +280,12 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
         return r;
 }
 
-void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
+int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
 {
         u32 old_irr = ioapic->irr;
         u32 mask = 1 << irq;
         union ioapic_redir_entry entry;
+        int ret = 1;
 
         if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
                 entry = ioapic->redirtbl[irq];
@@ -288,9 +296,10 @@ void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
                         ioapic->irr |= mask;
                         if ((!entry.fields.trig_mode && old_irr != ioapic->irr)
                             || !entry.fields.remote_irr)
-                                ioapic_service(ioapic, irq);
+                                ret = ioapic_service(ioapic, irq);
                 }
         }
+        return ret;
 }
 
 static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int pin,