KVM: Maintain back mapping from irqchip/pin to gsi

Maintain back mapping from irqchip/pin to gsi to speedup
interrupt acknowledgment notifications.

[avi: build fix on non-x86/ia64]

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

4 files changed, 25 insertions, 17 deletions

diff --git a/arch/ia64/include/asm/kvm.h b/arch/ia64/include/asm/kvm.h
index 18a7e49abbc5..bc90c75adf67 100644
--- a/arch/ia64/include/asm/kvm.h
+++ b/arch/ia64/include/asm/kvm.h
@@ -60,6 +60,7 @@ struct kvm_ioapic_state {
 #define KVM_IRQCHIP_PIC_MASTER   0
 #define KVM_IRQCHIP_PIC_SLAVE    1
 #define KVM_IRQCHIP_IOAPIC       2
+#define KVM_NR_IRQCHIPS          3
 
 #define KVM_CONTEXT_SIZE        8*1024
 
diff --git a/arch/x86/include/asm/kvm.h b/arch/x86/include/asm/kvm.h
index 4a5fe914dc59..f02e87a5206f 100644
--- a/arch/x86/include/asm/kvm.h
+++ b/arch/x86/include/asm/kvm.h
@@ -79,6 +79,7 @@ struct kvm_ioapic_state {
 #define KVM_IRQCHIP_PIC_MASTER   0
 #define KVM_IRQCHIP_PIC_SLAVE    1
 #define KVM_IRQCHIP_IOAPIC       2
+#define KVM_NR_IRQCHIPS          3
 
 /* for KVM_GET_REGS and KVM_SET_REGS */
 struct kvm_regs {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index f403e66557fb..cc2d7493598b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -131,7 +131,10 @@ struct kvm_kernel_irq_routing_entry {
         struct hlist_node link;
 };
 
+#ifdef __KVM_HAVE_IOAPIC
+
 struct kvm_irq_routing_table {
+        int chip[KVM_NR_IRQCHIPS][KVM_IOAPIC_NUM_PINS];
         struct kvm_kernel_irq_routing_entry *rt_entries;
         u32 nr_rt_entries;
         /*
@@ -141,6 +144,12 @@ struct kvm_irq_routing_table {
         struct hlist_head map[0];
 };
 
+#else
+
+struct kvm_irq_routing_table {};
+
+#endif
+
 struct kvm {
         spinlock_t mmu_lock;
         spinlock_t requests_lock;
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 81950f6f6fd9..59cf8dae0062 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -175,25 +175,16 @@ void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
         struct kvm_irq_ack_notifier *kian;
         struct hlist_node *n;
-        unsigned gsi = pin;
-        int i;
+        int gsi;
 
         trace_kvm_ack_irq(irqchip, pin);
 
-        for (i = 0; i < kvm->irq_routing->nr_rt_entries; i++) {
-                struct kvm_kernel_irq_routing_entry *e;
-                e = &kvm->irq_routing->rt_entries[i];
-                if (e->type == KVM_IRQ_ROUTING_IRQCHIP &&
-                    e->irqchip.irqchip == irqchip &&
-                    e->irqchip.pin == pin) {
-                        gsi = e->gsi;
-                        break;
-                }
-        }
-
-        hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list, link)
-                if (kian->gsi == gsi)
-                        kian->irq_acked(kian);
+        gsi = kvm->irq_routing->chip[irqchip][pin];
+        if (gsi != -1)
+                hlist_for_each_entry(kian, n, &kvm->arch.irq_ack_notifier_list,
+                                     link)
+                        if (kian->gsi == gsi)
+                                kian->irq_acked(kian);
 }
 
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
@@ -332,6 +323,9 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
                 }
                 e->irqchip.irqchip = ue->u.irqchip.irqchip;
                 e->irqchip.pin = ue->u.irqchip.pin + delta;
+                if (e->irqchip.pin >= KVM_IOAPIC_NUM_PINS)
+                        goto out;
+                rt->chip[ue->u.irqchip.irqchip][e->irqchip.pin] = ue->gsi;
                 break;
         case KVM_IRQ_ROUTING_MSI:
                 e->set = kvm_set_msi;
@@ -356,7 +350,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
                         unsigned flags)
 {
         struct kvm_irq_routing_table *new, *old;
-        u32 i, nr_rt_entries = 0;
+        u32 i, j, nr_rt_entries = 0;
         int r;
 
         for (i = 0; i < nr; ++i) {
@@ -377,6 +371,9 @@ int kvm_set_irq_routing(struct kvm *kvm,
         new->rt_entries = (void *)&new->map[nr_rt_entries];
 
         new->nr_rt_entries = nr_rt_entries;
+        for (i = 0; i < 3; i++)
+                for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
+                        new->chip[i][j] = -1;
 
         for (i = 0; i < nr; ++i) {
                 r = -EINVAL;