KVM: Drop kvm->irq_lock lock from irq injection path
[safe/jmp/linux-2.6] / virt / kvm / irq_comm.c
index a797fa5..15a83b9 100644 (file)
  */
 
 #include <linux/kvm_host.h>
+#include <trace/events/kvm.h>
+
+#include <asm/msidef.h>
+#ifdef CONFIG_IA64
+#include <asm/iosapic.h>
+#endif
+
 #include "irq.h"
 
 #include "ioapic.h"
 
-static void kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e,
-                           struct kvm *kvm, int level)
+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 irq_source_id, int level)
 {
 #ifdef CONFIG_X86
-       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 irq_source_id, int 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)
+{
+#ifdef CONFIG_IA64
+       return irq->delivery_mode ==
+               (IOSAPIC_LOWEST_PRIORITY << IOSAPIC_DELIVERY_SHIFT);
+#else
+       return irq->delivery_mode == APIC_DM_LOWEST;
 #endif
 }
 
-static void kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
-                              struct kvm *kvm, int level)
+int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
+               struct kvm_lapic_irq *irq)
 {
-       kvm_ioapic_set_irq(kvm->arch.vioapic, e->irqchip.pin, level);
+       int i, r = -1;
+       struct kvm_vcpu *vcpu, *lowest = NULL;
+
+       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");
+
+       kvm_for_each_vcpu(i, vcpu, kvm) {
+               if (!kvm_apic_present(vcpu))
+                       continue;
+
+               if (!kvm_apic_match_dest(vcpu, src, irq->shorthand,
+                                       irq->dest_id, irq->dest_mode))
+                       continue;
+
+               if (!kvm_is_dm_lowest_prio(irq)) {
+                       if (r < 0)
+                               r = 0;
+                       r += kvm_apic_set_irq(vcpu, irq);
+               } else {
+                       if (!lowest)
+                               lowest = vcpu;
+                       else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
+                               lowest = vcpu;
+               }
+       }
+
+       if (lowest)
+               r = kvm_apic_set_irq(lowest, irq);
+
+       return r;
 }
 
-/* This should be called with the kvm->lock mutex held */
-void kvm_set_irq(struct kvm *kvm, int irq_source_id, int irq, int level)
+static int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
+                      struct kvm *kvm, int irq_source_id, int level)
 {
-       struct kvm_kernel_irq_routing_entry *e;
-       unsigned long *irq_state = (unsigned long *)&kvm->arch.irq_states[irq];
+       struct kvm_lapic_irq irq;
 
-       /* Logical OR for level trig interrupt */
-       if (level)
-               set_bit(irq_source_id, irq_state);
-       else
-               clear_bit(irq_source_id, irq_state);
+       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 &
+                       MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT;
+       irq.dest_mode = (1 << MSI_ADDR_DEST_MODE_SHIFT) & e->msi.address_lo;
+       irq.trig_mode = (1 << MSI_DATA_TRIGGER_SHIFT) & e->msi.data;
+       irq.delivery_mode = e->msi.data & 0x700;
+       irq.level = 1;
+       irq.shorthand = 0;
+
+       /* TODO Deal with RH bit of MSI message address */
+       return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
+}
+
+/*
+ * 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, u32 irq, int level)
+{
+       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;
+
+       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)
-                       e->set(e, kvm, !!(*irq_state));
+       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);
+       }
+
+       return ret;
 }
 
-void kvm_notify_acked_irq(struct kvm *kvm, unsigned gsi)
+void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
 {
        struct kvm_irq_ack_notifier *kian;
        struct hlist_node *n;
-
-       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)
 {
-       hlist_add_head(&kian->link, &kvm->arch.irq_ack_notifier_list);
+       mutex_lock(&kvm->irq_lock);
+       hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
+       mutex_unlock(&kvm->irq_lock);
 }
 
-void kvm_unregister_irq_ack_notifier(struct kvm_irq_ack_notifier *kian)
+void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
+                                   struct kvm_irq_ack_notifier *kian)
 {
-       hlist_del_init(&kian->link);
+       mutex_lock(&kvm->irq_lock);
+       hlist_del_init_rcu(&kian->link);
+       mutex_unlock(&kvm->irq_lock);
+       synchronize_rcu();
 }
 
-/* The caller must hold kvm->lock mutex */
 int kvm_request_irq_source_id(struct kvm *kvm)
 {
        unsigned long *bitmap = &kvm->arch.irq_sources_bitmap;
-       int irq_source_id = find_first_zero_bit(bitmap,
+       int irq_source_id;
+
+       mutex_lock(&kvm->irq_lock);
+       irq_source_id = find_first_zero_bit(bitmap,
                                sizeof(kvm->arch.irq_sources_bitmap));
 
        if (irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
@@ -94,6 +225,7 @@ int kvm_request_irq_source_id(struct kvm *kvm)
 
        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
        set_bit(irq_source_id, bitmap);
+       mutex_unlock(&kvm->irq_lock);
 
        return irq_source_id;
 }
@@ -104,27 +236,40 @@ void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id)
 
        ASSERT(irq_source_id != KVM_USERSPACE_IRQ_SOURCE_ID);
 
+       mutex_lock(&kvm->irq_lock);
        if (irq_source_id < 0 ||
            irq_source_id >= sizeof(kvm->arch.irq_sources_bitmap)) {
                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);
 }
 
 void kvm_register_irq_mask_notifier(struct kvm *kvm, int irq,
                                    struct kvm_irq_mask_notifier *kimn)
 {
+       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);
 }
 
 void kvm_unregister_irq_mask_notifier(struct kvm *kvm, int irq,
                                      struct kvm_irq_mask_notifier *kimn)
 {
-       hlist_del(&kimn->link);
+       mutex_lock(&kvm->irq_lock);
+       hlist_del_rcu(&kimn->link);
+       mutex_unlock(&kvm->irq_lock);
+       synchronize_rcu();
 }
 
 void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
@@ -132,31 +277,40 @@ void kvm_fire_mask_notifiers(struct kvm *kvm, int irq, bool mask)
        struct kvm_irq_mask_notifier *kimn;
        struct hlist_node *n;
 
-       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)
 {
-       __kvm_free_irq_routing(&kvm->irq_routing);
+       /* Called only during vm destruction. Nobody can use the pointer
+          at this stage */
+       kfree(kvm->irq_routing);
 }
 
-int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
-                       const struct kvm_irq_routing_entry *ue)
+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;
        switch (ue->type) {
        case KVM_IRQ_ROUTING_IRQCHIP:
                delta = 0;
@@ -165,21 +319,32 @@ int setup_routing_entry(struct kvm_kernel_irq_routing_entry *e,
                        e->set = kvm_set_pic_irq;
                        break;
                case KVM_IRQCHIP_PIC_SLAVE:
-                               e->set = kvm_set_pic_irq;
+                       e->set = kvm_set_pic_irq;
                        delta = 8;
                        break;
                case KVM_IRQCHIP_IOAPIC:
-                               e->set = kvm_set_ioapic_irq;
+                       e->set = kvm_set_ioapic_irq;
                        break;
                default:
                        goto out;
                }
                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;
+               e->msi.address_lo = ue->u.msi.address_lo;
+               e->msi.address_hi = ue->u.msi.address_hi;
+               e->msi.data = ue->u.msi.data;
                break;
        default:
                goto out;
        }
+
+       hlist_add_head(&e->link, &rt->map[e->gsi]);
        r = 0;
 out:
        return r;
@@ -191,43 +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->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);
-       mutex_unlock(&kvm->lock);
+       mutex_lock(&kvm->irq_lock);
+       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;
 }
 
@@ -237,8 +412,6 @@ out:
 #define ROUTING_ENTRY1(irq) IOAPIC_ROUTING_ENTRY(irq)
 
 #ifdef CONFIG_X86
-#define SELECT_PIC(irq) \
-       ((irq) < 8 ? KVM_IRQCHIP_PIC_MASTER : KVM_IRQCHIP_PIC_SLAVE)
 #  define PIC_ROUTING_ENTRY(irq) \
        { .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP,  \
          .u.irqchip.irqchip = SELECT_PIC(irq), .u.irqchip.pin = (irq) % 8 }