KVM: Drop kvm->irq_lock lock from irq injection path
[safe/jmp/linux-2.6] / virt / kvm / irq_comm.c
index bb8a1b5..15a83b9 100644 (file)
@@ -20,6 +20,7 @@
  */
 
 #include <linux/kvm_host.h>
+#include <trace/events/kvm.h>
 
 #include <asm/msidef.h>
 #ifdef CONFIG_IA64
 
 #include "ioapic.h"
 
+static inline int kvm_irq_line_state(unsigned long *irq_state,
+                                    int irq_source_id, int level)
+{
+       /* Logical OR for level trig interrupt */
+       if (level)
+               set_bit(irq_source_id, irq_state);
+       else
+               clear_bit(irq_source_id, irq_state);
+
+       return !!(*irq_state);
+}
+
 static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
-                          struct kvm *kvm, int level)
+                          struct kvm *kvm, int irq_source_id, int level)
 {
 #ifdef CONFIG_X86
-       return kvm_pic_set_irq(pic_irqchip(kvm), e->irqchip.pin, level);
+       struct kvm_pic *pic = pic_irqchip(kvm);
+       level = kvm_irq_line_state(&pic->irq_states[e->irqchip.pin],
+                                  irq_source_id, level);
+       return kvm_pic_set_irq(pic, e->irqchip.pin, level);
 #else
        return -1;
 #endif
 }
 
 static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
-                             struct kvm *kvm, int level)
+                             struct kvm *kvm, int irq_source_id, int level)
 {
-       return kvm_ioapic_set_irq(kvm->arch.vioapic, e->irqchip.pin, level);
+       struct kvm_ioapic *ioapic = kvm->arch.vioapic;
+       level = kvm_irq_line_state(&ioapic->irq_states[e->irqchip.pin],
+                                  irq_source_id, level);
+
+       return kvm_ioapic_set_irq(ioapic, e->irqchip.pin, level);
 }
 
 inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
@@ -62,8 +82,6 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
        int i, r = -1;
        struct kvm_vcpu *vcpu, *lowest = NULL;
 
-       WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
        if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
                        kvm_is_dm_lowest_prio(irq))
                printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
@@ -95,10 +113,15 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 }
 
 static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
-                      struct kvm *kvm, int level)
+                      struct kvm *kvm, int irq_source_id, int level)
 {
        struct kvm_lapic_irq irq;
 
+       if (!level)
+               return -1;
+
+       trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
+
        irq.dest_id = (e->msi.address_lo &
                        MSI_ADDR_DEST_ID_MASK) >> MSI_ADDR_DEST_ID_SHIFT;
        irq.vector = (e->msi.data &
@@ -113,72 +136,67 @@ static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
        return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
 }
 
-/* This should be called with the kvm->irq_lock mutex held
+/*
  * Return value:
  *  < 0   Interrupt was ignored (masked or not delivered for other reasons)
  *  = 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;
-       unsigned long *irq_state, sig_level;
-       int ret = -1;
-
-       WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
-       if (irq < KVM_IOAPIC_NUM_PINS) {
-               irq_state = (unsigned long *)&kvm->arch.irq_states[irq];
+       struct kvm_kernel_irq_routing_entry *e, irq_set[KVM_NR_IRQCHIPS];
+       int ret = -1, i = 0;
+       struct kvm_irq_routing_table *irq_rt;
+       struct hlist_node *n;
 
-               /* Logical OR for level trig interrupt */
-               if (level)
-                       set_bit(irq_source_id, irq_state);
-               else
-                       clear_bit(irq_source_id, irq_state);
-               sig_level = !!(*irq_state);
-       } else /* Deal with MSI/MSI-X */
-               sig_level = 1;
+       trace_kvm_set_irq(irq, level, irq_source_id);
 
        /* Not possible to detect if the guest uses the PIC or the
         * 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) {
-                       int r = e->set(e, kvm, sig_level);
-                       if (r < 0)
-                               continue;
+       rcu_read_lock();
+       irq_rt = rcu_dereference(kvm->irq_routing);
+       if (irq < irq_rt->nr_rt_entries)
+               hlist_for_each_entry(e, n, &irq_rt->map[irq], link)
+                       irq_set[i++] = *e;
+       rcu_read_unlock();
+
+       while(i--) {
+               int r;
+               r = irq_set[i].set(&irq_set[i], kvm, irq_source_id, level);
+               if (r < 0)
+                       continue;
+
+               ret = r + ((ret < 0) ? 0 : ret);
+       }
 
-                       ret = r + ((ret < 0) ? 0 : ret);
-               }
        return ret;
 }
 
 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;
-
-       list_for_each_entry(e, &kvm->irq_routing, link)
-               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);
+       int gsi;
+
+       trace_kvm_ack_irq(irqchip, pin);
+
+       rcu_read_lock();
+       gsi = rcu_dereference(kvm->irq_routing)->chip[irqchip][pin];
+       if (gsi != -1)
+               hlist_for_each_entry_rcu(kian, n, &kvm->irq_ack_notifier_list,
+                                        link)
+                       if (kian->gsi == gsi)
+                               kian->irq_acked(kian);
+       rcu_read_unlock();
 }
 
 void kvm_register_irq_ack_notifier(struct kvm *kvm,
                                   struct kvm_irq_ack_notifier *kian)
 {
        mutex_lock(&kvm->irq_lock);
-       hlist_add_head(&kian->link, &kvm->arch.irq_ack_notifier_list);
+       hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
        mutex_unlock(&kvm->irq_lock);
 }
 
@@ -186,8 +204,9 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
                                    struct kvm_irq_ack_notifier *kian)
 {
        mutex_lock(&kvm->irq_lock);
-       hlist_del_init(&kian->link);
+       hlist_del_init_rcu(&kian->link);
        mutex_unlock(&kvm->irq_lock);
+       synchronize_rcu();
 }
 
 int kvm_request_irq_source_id(struct kvm *kvm)
@@ -223,8 +242,14 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
                printk(KERN_ERR "kvm: IRQ source ID out of range!\n");
                return;
        }
-       for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++)
-               clear_bit(irq_source_id, &kvm->arch.irq_states[i]);
+       for (i = 0; i < KVM_IOAPIC_NUM_PINS; i++) {
+               clear_bit(irq_source_id, &kvm->arch.vioapic->irq_states[i]);
+               if (i >= 16)
+                       continue;
+#ifdef CONFIG_X86
+               clear_bit(irq_source_id, &pic_irqchip(kvm)->irq_states[i]);
+#endif
+       }
        clear_bit(irq_source_id, &kvm->arch.irq_sources_bitmap);
        mutex_unlock(&kvm->irq_lock);
 }
@@ -234,7 +259,7 @@ void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
 {
        mutex_lock(&kvm->irq_lock);
        kimn->irq = irq;
-       hlist_add_head(&kimn->link, &kvm->mask_notifier_list);
+       hlist_add_head_rcu(&kimn->link, &kvm->mask_notifier_list);
        mutex_unlock(&kvm->irq_lock);
 }
 
@@ -242,8 +267,9 @@ void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                                      struct kvm_irq_mask_notifier *kimn)
 {
        mutex_lock(&kvm->irq_lock);
-       hlist_del(&kimn->link);
+       hlist_del_rcu(&kimn->link);
        mutex_unlock(&kvm->irq_lock);
+       synchronize_rcu();
 }
 
 void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
@@ -251,33 +277,37 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
        struct kvm_irq_mask_notifier *kimn;
        struct hlist_node *n;
 
-       WARN_ON(!mutex_is_locked(&kvm->irq_lock));
-
-       hlist_for_each_entry(kimn, n, &kvm->mask_notifier_list, link)
+       rcu_read_lock();
+       hlist_for_each_entry_rcu(kimn, n, &kvm->mask_notifier_list, link)
                if (kimn->irq == irq)
                        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);
+       rcu_read_unlock();
 }
 
 void kvm_free_irq_routing(struct kvm *kvm)
 {
-       mutex_lock(&kvm->irq_lock);
-       __kvm_free_irq_routing(&kvm->irq_routing);
-       mutex_unlock(&kvm->irq_lock);
+       /* Called only during vm destruction. Nobody can use the pointer
+          at this stage */
+       kfree(kvm->irq_routing);
 }
 
-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;
@@ -300,6 +330,9 @@ static int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
                }
                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;
@@ -310,6 +343,8 @@ 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;
@@ -321,43 +356,53 @@ 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, j, 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 < 3; i++)
+               for (j = 0; j < KVM_IOAPIC_NUM_PINS; j++)
+                       new->chip[i][j] = -1;
+
+       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;
+       rcu_assign_pointer(kvm->irq_routing, new);
        mutex_unlock(&kvm->irq_lock);
+       synchronize_rcu();
 
+       new = old;
        r = 0;
 
 out:
-       kfree(e);
-       __kvm_free_irq_routing(&irq_list);
+       kfree(new);
        return r;
 }