KVM: x86: Remove support for reporting coalesced APIC IRQs

Since the arrival of posted interrupt support we can no longer guarantee
that coalesced IRQs are always reported to the IRQ source. Moreover,
accumulated APIC timer events could cause a busy loop when a VCPU should
rather be halted. The consensus is to remove coalesced tracking from the
LAPIC.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index e2e6b4473a96..ef1817b61cf4 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -91,7 +91,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
                 if (!kvm_is_dm_lowest_prio(irq)) {
                         if (r < 0)
                                 r = 0;
-                        r += kvm_apic_set_irq(vcpu, irq, dest_map);
+                        kvm_apic_set_irq(vcpu, irq, dest_map);
+                        r++;
                 } else if (kvm_lapic_enabled(vcpu)) {
                         if (!lowest)
                                 lowest = vcpu;
@@ -100,8 +101,10 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
                 }
         }
 
-        if (lowest)
-                r = kvm_apic_set_irq(lowest, irq, dest_map);
+        if (lowest) {
+                kvm_apic_set_irq(lowest, irq, dest_map);
+                r = 1;
+        }
 
         return r;
 }