KVM: x86: Use vector-hashing to deliver lowest-priority interrupts

[cascardo/linux.git] / arch / x86 / kvm / irq_comm.c

diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 8fc89ef..3721736 100644 (file)
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -34,6 +34,7 @@
 #include "lapic.h"
 
 #include "hyperv.h"
+#include "x86.h"
 
 static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
                           struct kvm *kvm, int irq_source_id, int level,
@@ -57,6 +58,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 {
        int i, r = -1;
        struct kvm_vcpu *vcpu, *lowest = NULL;
+       unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
+       unsigned int dest_vcpus = 0;
 
        if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
                        kvm_lowest_prio_delivery(irq)) {
@@ -67,6 +70,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
        if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map))
                return r;
 
+       memset(dest_vcpu_bitmap, 0, sizeof(dest_vcpu_bitmap));
+
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (!kvm_apic_present(vcpu))
                        continue;
@@ -80,13 +85,25 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
                                r = 0;
                        r += kvm_apic_set_irq(vcpu, irq, dest_map);
                } else if (kvm_lapic_enabled(vcpu)) {
-                       if (!lowest)
-                               lowest = vcpu;
-                       else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
-                               lowest = vcpu;
+                       if (!kvm_vector_hashing_enabled()) {
+                               if (!lowest)
+                                       lowest = vcpu;
+                               else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
+                                       lowest = vcpu;
+                       } else {
+                               __set_bit(i, dest_vcpu_bitmap);
+                               dest_vcpus++;
+                       }
                }
        }
 
+       if (dest_vcpus != 0) {
+               int idx = kvm_vector_to_index(irq->vector, dest_vcpus,
+                                       dest_vcpu_bitmap, KVM_MAX_VCPUS);
+
+               lowest = kvm_get_vcpu(kvm, idx);
+       }
+
        if (lowest)
                r = kvm_apic_set_irq(lowest, irq, dest_map);