KVM: Change irq routing table to use gsi indexed array
Gleb Natapov [Mon, 24 Aug 2009 08:54:20 +0000 (11:54 +0300)]
Use gsi indexed array instead of scanning all entries on each interrupt
injection.

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

include/linux/kvm_host.h
virt/kvm/irq_comm.c
virt/kvm/kvm_main.c

index 1c7f8c4..f403e66 100644 (file)
@@ -128,7 +128,17 @@ struct kvm_kernel_irq_routing_entry {
                } irqchip;
                struct msi_msg msi;
        };
-       struct list_head link;
+       struct hlist_node link;
+};
+
+struct kvm_irq_routing_table {
+       struct kvm_kernel_irq_routing_entry *rt_entries;
+       u32 nr_rt_entries;
+       /*
+        * Array indexed by gsi. Each entry contains list of irq chips
+        * the gsi is connected to.
+        */
+       struct hlist_head map[0];
 };
 
 struct kvm {
@@ -166,7 +176,7 @@ struct kvm {
 
        struct mutex irq_lock;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
-       struct list_head irq_routing; /* of kvm_kernel_irq_routing_entry */
+       struct kvm_irq_routing_table *irq_routing;
        struct hlist_head mask_notifier_list;
 #endif
 
@@ -390,7 +400,12 @@ void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                                      struct kvm_irq_mask_notifier *kimn);
 void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask);
 
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level);
+#ifdef __KVM_HAVE_IOAPIC
+void kvm_get_intr_delivery_bitmask(struct kvm_ioapic *ioapic,
+                                  union kvm_ioapic_redirect_entry *entry,
+                                  unsigned long *deliver_bitmask);
+#endif
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level);
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin);
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
                                   struct kvm_irq_ack_notifier *kian);
index 9783f5c..81950f6 100644 (file)
@@ -144,10 +144,12 @@ static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
  *  = 0   Interrupt was coalesced (previous irq is still pending)
  *  > 0   Number of CPUs interrupt was delivered to
  */
-int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level)
 {
        struct kvm_kernel_irq_routing_entry *e;
        int ret = -1;
+       struct kvm_irq_routing_table *irq_rt;
+       struct hlist_node *n;
 
        trace_kvm_set_irq(irq, level, irq_source_id);
 
@@ -157,8 +159,9 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
         * IOAPIC.  So set the bit in both. The guest will ignore
         * writes to the unused one.
         */
-       list_for_each_entry(e, &kvm->irq_routing, link)
-               if (e->gsi == irq) {
+       irq_rt = kvm->irq_routing;
+       if (irq < irq_rt->nr_rt_entries)
+               hlist_for_each_entry(e, n, &irq_rt->map[irq], link) {
                        int r = e->set(e, kvm, irq_source_id, level);
                        if (r < 0)
                                continue;
@@ -170,20 +173,23 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
 
 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
-       struct kvm_kernel_irq_routing_entry *e;
        struct kvm_irq_ack_notifier *kian;
        struct hlist_node *n;
        unsigned gsi = pin;
+       int i;
 
        trace_kvm_ack_irq(irqchip, pin);
 
-       list_for_each_entry(e, &kvm->irq_routing, link)
+       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)
@@ -280,26 +286,30 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
                        kimn->func(kimn, mask);
 }
 
-static void __kvm_free_irq_routing(struct list_head *irq_routing)
-{
-       struct kvm_kernel_irq_routing_entry *e, *n;
-
-       list_for_each_entry_safe(e, n, irq_routing, link)
-               kfree(e);
-}
-
 void kvm_free_irq_routing(struct kvm *kvm)
 {
        mutex_lock(&kvm->irq_lock);
-       __kvm_free_irq_routing(&kvm->irq_routing);
+       kfree(kvm->irq_routing);
        mutex_unlock(&kvm->irq_lock);
 }
 
-static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
+static int setup_routing_entry(struct kvm_irq_routing_table *rt,
+                              struct kvm_kernel_irq_routing_entry *e,
                               const struct kvm_irq_routing_entry *ue)
 {
        int r = -EINVAL;
        int delta;
+       struct kvm_kernel_irq_routing_entry *ei;
+       struct hlist_node *n;
+
+       /*
+        * Do not allow GSI to be mapped to the same irqchip more than once.
+        * Allow only one to one mapping between GSI and MSI.
+        */
+       hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
+               if (ei->type == KVM_IRQ_ROUTING_MSI ||
+                   ue->u.irqchip.irqchip == ei->irqchip.irqchip)
+                       return r;
 
        e->gsi = ue->gsi;
        e->type = ue->type;
@@ -332,6 +342,8 @@ static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
        default:
                goto out;
        }
+
+       hlist_add_head(&e->link, &rt->map[e->gsi]);
        r = 0;
 out:
        return r;
@@ -343,43 +355,49 @@ int kvm_set_irq_routing(struct kvm *kvm,
                        unsigned nr,
                        unsigned flags)
 {
-       struct list_head irq_list = LIST_HEAD_INIT(irq_list);
-       struct list_head tmp = LIST_HEAD_INIT(tmp);
-       struct kvm_kernel_irq_routing_entry *e = NULL;
-       unsigned i;
+       struct kvm_irq_routing_table *new, *old;
+       u32 i, nr_rt_entries = 0;
        int r;
 
        for (i = 0; i < nr; ++i) {
+               if (ue[i].gsi >= KVM_MAX_IRQ_ROUTES)
+                       return -EINVAL;
+               nr_rt_entries = max(nr_rt_entries, ue[i].gsi);
+       }
+
+       nr_rt_entries += 1;
+
+       new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head))
+                     + (nr * sizeof(struct kvm_kernel_irq_routing_entry)),
+                     GFP_KERNEL);
+
+       if (!new)
+               return -ENOMEM;
+
+       new->rt_entries = (void *)&new->map[nr_rt_entries];
+
+       new->nr_rt_entries = nr_rt_entries;
+
+       for (i = 0; i < nr; ++i) {
                r = -EINVAL;
-               if (ue->gsi >= KVM_MAX_IRQ_ROUTES)
-                       goto out;
                if (ue->flags)
                        goto out;
-               r = -ENOMEM;
-               e = kzalloc(sizeof(*e), GFP_KERNEL);
-               if (!e)
-                       goto out;
-               r = setup_routing_entry(e, ue);
+               r = setup_routing_entry(new, &new->rt_entries[i], ue);
                if (r)
                        goto out;
                ++ue;
-               list_add(&e->link, &irq_list);
-               e = NULL;
        }
 
        mutex_lock(&kvm->irq_lock);
-       list_splice(&kvm->irq_routing, &tmp);
-       INIT_LIST_HEAD(&kvm->irq_routing);
-       list_splice(&irq_list, &kvm->irq_routing);
-       INIT_LIST_HEAD(&irq_list);
-       list_splice(&tmp, &irq_list);
+       old = kvm->irq_routing;
+       kvm->irq_routing = new;
        mutex_unlock(&kvm->irq_lock);
 
+       new = old;
        r = 0;
 
 out:
-       kfree(e);
-       __kvm_free_irq_routing(&irq_list);
+       kfree(new);
        return r;
 }
 
index 22b520b..3bee948 100644 (file)
@@ -957,7 +957,6 @@ static struct kvm *kvm_create_vm(void)
        if (IS_ERR(kvm))
                goto out;
 #ifdef CONFIG_HAVE_KVM_IRQCHIP
-       INIT_LIST_HEAD(&kvm->irq_routing);
        INIT_HLIST_HEAD(&kvm->mask_notifier_list);
 #endif