9 files changed, 101 insertions, 75 deletions

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index b2e4d16dd39..d0ad538f008 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -241,10 +241,10 @@ static int handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         return 0;
 mmio:
         if (p->dir)
-                r = kvm_io_bus_read(&vcpu->kvm->mmio_bus, p->addr,
+                r = kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, p->addr,
                                     p->size, &p->data);
         else
-                r = kvm_io_bus_write(&vcpu->kvm->mmio_bus, p->addr,
+                r = kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, p->addr,
                                      p->size, &p->data);
         if (r)
                 printk(KERN_ERR"kvm: No iodevice found! addr:%lx\n", p->addr);
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 15578f180e5..4b433de02e5 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -645,13 +645,13 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
         kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
 
         kvm_iodevice_init(&pit->dev, &pit_dev_ops);
-        ret = __kvm_io_bus_register_dev(&kvm->pio_bus, &pit->dev);
+        ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, &pit->dev);
         if (ret < 0)
                 goto fail;
 
         if (flags & KVM_PIT_SPEAKER_DUMMY) {
                 kvm_iodevice_init(&pit->speaker_dev, &speaker_dev_ops);
-                ret = __kvm_io_bus_register_dev(&kvm->pio_bus,
+                ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS,
                                                 &pit->speaker_dev);
                 if (ret < 0)
                         goto fail_unregister;
@@ -660,7 +660,7 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm, u32 flags)
         return pit;
 
 fail_unregister:
-        __kvm_io_bus_unregister_dev(&kvm->pio_bus, &pit->dev);
+        kvm_io_bus_unregister_dev(kvm, KVM_PIO_BUS, &pit->dev);
 
 fail:
         if (pit->irq_source_id >= 0)
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index d057c0cbd24..b7d145b2095 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -533,7 +533,9 @@ struct kvm_pic *kvm_create_pic(struct kvm *kvm)
          * Initialize PIO device
          */
         kvm_iodevice_init(&s->dev, &picdev_ops);
-        ret = kvm_io_bus_register_dev(kvm, &kvm->pio_bus, &s->dev);
+        down_write(&kvm->slots_lock);
+        ret = kvm_io_bus_register_dev(kvm, KVM_PIO_BUS, &s->dev);
+        up_write(&kvm->slots_lock);
         if (ret < 0) {
                 kfree(s);
                 return NULL;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 28127c936c3..9b42673df4a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2851,7 +2851,7 @@ static int vcpu_mmio_write(struct kvm_vcpu *vcpu, gpa_t addr, int len,
             !kvm_iodevice_write(&vcpu->arch.apic->dev, addr, len, v))
                 return 0;
 
-        return kvm_io_bus_write(&vcpu->kvm->mmio_bus, addr, len, v);
+        return kvm_io_bus_write(vcpu->kvm, KVM_MMIO_BUS, addr, len, v);
 }
 
 static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
@@ -2860,7 +2860,7 @@ static int vcpu_mmio_read(struct kvm_vcpu *vcpu, gpa_t addr, int len, void *v)
             !kvm_iodevice_read(&vcpu->arch.apic->dev, addr, len, v))
                 return 0;
 
-        return kvm_io_bus_read(&vcpu->kvm->mmio_bus, addr, len, v);
+        return kvm_io_bus_read(vcpu->kvm, KVM_MMIO_BUS, addr, len, v);
 }
 
 static int kvm_read_guest_virt(gva_t addr, void *val, unsigned int bytes,
@@ -3345,11 +3345,12 @@ static int kernel_pio(struct kvm_vcpu *vcpu, void *pd)
         int r;
 
         if (vcpu->arch.pio.in)
-                r = kvm_io_bus_read(&vcpu->kvm->pio_bus, vcpu->arch.pio.port,
+                r = kvm_io_bus_read(vcpu->kvm, KVM_PIO_BUS, vcpu->arch.pio.port,
                                     vcpu->arch.pio.size, pd);
         else
-                r = kvm_io_bus_write(&vcpu->kvm->pio_bus, vcpu->arch.pio.port,
-                                     vcpu->arch.pio.size, pd);
+                r = kvm_io_bus_write(vcpu->kvm, KVM_PIO_BUS,
+                                     vcpu->arch.pio.port, vcpu->arch.pio.size,
+                                     pd);
         return r;
 }
 
@@ -3360,7 +3361,7 @@ static int pio_string_write(struct kvm_vcpu *vcpu)
         int i, r = 0;
 
         for (i = 0; i < io->cur_count; i++) {
-                if (kvm_io_bus_write(&vcpu->kvm->pio_bus,
+                if (kvm_io_bus_write(vcpu->kvm, KVM_PIO_BUS,
                                      io->port, io->size, pd)) {
                         r = -EOPNOTSUPP;
                         break;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 20941c0f404..5e9cb902550 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -57,20 +57,20 @@ struct kvm_io_bus {
         struct kvm_io_device *devs[NR_IOBUS_DEVS];
 };
 
-void kvm_io_bus_init(struct kvm_io_bus *bus);
-void kvm_io_bus_destroy(struct kvm_io_bus *bus);
-int kvm_io_bus_write(struct kvm_io_bus *bus, gpa_t addr, int len,
-                     const void *val);
-int kvm_io_bus_read(struct kvm_io_bus *bus, gpa_t addr, int len,
+enum kvm_bus {
+        KVM_MMIO_BUS,
+        KVM_PIO_BUS,
+        KVM_NR_BUSES
+};
+
+int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
+                     int len, const void *val);
+int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr, int len,
                     void *val);
-int __kvm_io_bus_register_dev(struct kvm_io_bus *bus,
-                               struct kvm_io_device *dev);
-int kvm_io_bus_register_dev(struct kvm *kvm, struct kvm_io_bus *bus,
+int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx,
                             struct kvm_io_device *dev);
-void __kvm_io_bus_unregister_dev(struct kvm_io_bus *bus,
-                                 struct kvm_io_device *dev);
-void kvm_io_bus_unregister_dev(struct kvm *kvm, struct kvm_io_bus *bus,
-                               struct kvm_io_device *dev);
+int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+                              struct kvm_io_device *dev);
 
 struct kvm_vcpu {
         struct kvm *kvm;
@@ -171,8 +171,7 @@ struct kvm {
         atomic_t online_vcpus;
         struct list_head vm_list;
         struct mutex lock;
-        struct kvm_io_bus mmio_bus;
-        struct kvm_io_bus pio_bus;
+        struct kvm_io_bus *buses[KVM_NR_BUSES];
 #ifdef CONFIG_HAVE_KVM_EVENTFD
         struct {
                 spinlock_t        lock;
diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index d68e6c68e0f..a736a93ca7b 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -110,7 +110,9 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
         dev->kvm = kvm;
         kvm->coalesced_mmio_dev = dev;
 
-        ret = kvm_io_bus_register_dev(kvm, &kvm->mmio_bus, &dev->dev);
+        down_write(&kvm->slots_lock);
+        ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &dev->dev);
+        up_write(&kvm->slots_lock);
         if (ret < 0)
                 goto out_free_dev;
 
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index a9d3fc6c681..315a586ec4d 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -463,7 +463,7 @@ static int
 kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 {
         int                       pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
-        struct kvm_io_bus        *bus = pio ? &kvm->pio_bus : &kvm->mmio_bus;
+        enum kvm_bus              bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
         struct _ioeventfd        *p;
         struct eventfd_ctx       *eventfd;
         int                       ret;
@@ -518,7 +518,7 @@ kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 
         kvm_iodevice_init(&p->dev, &ioeventfd_ops);
 
-        ret = __kvm_io_bus_register_dev(bus, &p->dev);
+        ret = kvm_io_bus_register_dev(kvm, bus_idx, &p->dev);
         if (ret < 0)
                 goto unlock_fail;
 
@@ -542,7 +542,7 @@ static int
 kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 {
         int                       pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
-        struct kvm_io_bus        *bus = pio ? &kvm->pio_bus : &kvm->mmio_bus;
+        enum kvm_bus              bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
         struct _ioeventfd        *p, *tmp;
         struct eventfd_ctx       *eventfd;
         int                       ret = -ENOENT;
@@ -565,7 +565,7 @@ kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
                 if (!p->wildcard && p->datamatch != args->datamatch)
                         continue;
 
-                __kvm_io_bus_unregister_dev(bus, &p->dev);
+                kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
                 ioeventfd_release(p);
                 ret = 0;
                 break;
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 38a2d20b89d..f326a6f301c 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -372,7 +372,9 @@ int kvm_ioapic_init(struct kvm *kvm)
         kvm_ioapic_reset(ioapic);
         kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
         ioapic->kvm = kvm;
-        ret = kvm_io_bus_register_dev(kvm, &kvm->mmio_bus, &ioapic->dev);
+        down_write(&kvm->slots_lock);
+        ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &ioapic->dev);
+        up_write(&kvm->slots_lock);
         if (ret < 0)
                 kfree(ioapic);
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c680f7b64c6..659bc12ad16 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -85,6 +85,8 @@ static long kvm_vcpu_ioctl(struct file *file, unsigned int ioctl,
 static int hardware_enable_all(void);
 static void hardware_disable_all(void);
 
+static void kvm_io_bus_destroy(struct kvm_io_bus *bus);
+
 static bool kvm_rebooting;
 
 static bool largepages_enabled = true;
@@ -367,7 +369,7 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
 
 static struct kvm *kvm_create_vm(void)
 {
-        int r = 0;
+        int r = 0, i;
         struct kvm *kvm = kvm_arch_create_vm();
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
         struct page *page;
@@ -391,6 +393,14 @@ static struct kvm *kvm_create_vm(void)
                 goto out_err;
         if (init_srcu_struct(&kvm->srcu))
                 goto out_err;
+        for (i = 0; i < KVM_NR_BUSES; i++) {
+                kvm->buses[i] = kzalloc(sizeof(struct kvm_io_bus),
+                                        GFP_KERNEL);
+                if (!kvm->buses[i]) {
+                        cleanup_srcu_struct(&kvm->srcu);
+                        goto out_err;
+                }
+        }
 
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
         page = alloc_page(GFP_KERNEL | __GFP_ZERO);
@@ -416,11 +426,9 @@ static struct kvm *kvm_create_vm(void)
         atomic_inc(&kvm->mm->mm_count);
         spin_lock_init(&kvm->mmu_lock);
         spin_lock_init(&kvm->requests_lock);
-        kvm_io_bus_init(&kvm->pio_bus);
         kvm_eventfd_init(kvm);
         mutex_init(&kvm->lock);
         mutex_init(&kvm->irq_lock);
-        kvm_io_bus_init(&kvm->mmio_bus);
         init_rwsem(&kvm->slots_lock);
         atomic_set(&kvm->users_count, 1);
         spin_lock(&kvm_lock);
@@ -435,6 +443,8 @@ out:
 out_err:
         hardware_disable_all();
 out_err_nodisable:
+        for (i = 0; i < KVM_NR_BUSES; i++)
+                kfree(kvm->buses[i]);
         kfree(kvm->memslots);
         kfree(kvm);
         return ERR_PTR(r);
@@ -480,6 +490,7 @@ void kvm_free_physmem(struct kvm *kvm)
 
 static void kvm_destroy_vm(struct kvm *kvm)
 {
+        int i;
         struct mm_struct *mm = kvm->mm;
 
         kvm_arch_sync_events(kvm);
@@ -487,8 +498,8 @@ static void kvm_destroy_vm(struct kvm *kvm)
         list_del(&kvm->vm_list);
         spin_unlock(&kvm_lock);
         kvm_free_irq_routing(kvm);
-        kvm_io_bus_destroy(&kvm->pio_bus);
-        kvm_io_bus_destroy(&kvm->mmio_bus);
+        for (i = 0; i < KVM_NR_BUSES; i++)
+                kvm_io_bus_destroy(kvm->buses[i]);
         kvm_coalesced_mmio_free(kvm);
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
         mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
@@ -1949,12 +1960,7 @@ static struct notifier_block kvm_reboot_notifier = {
         .priority = 0,
 };
 
-void kvm_io_bus_init(struct kvm_io_bus *bus)
-{
-        memset(bus, 0, sizeof(*bus));
-}
-
-void kvm_io_bus_destroy(struct kvm_io_bus *bus)
+static void kvm_io_bus_destroy(struct kvm_io_bus *bus)
 {
         int i;
 
@@ -1963,13 +1969,15 @@ void kvm_io_bus_destroy(struct kvm_io_bus *bus)
 
                 kvm_iodevice_destructor(pos);
         }
+        kfree(bus);
 }
 
 /* kvm_io_bus_write - called under kvm->slots_lock */
-int kvm_io_bus_write(struct kvm_io_bus *bus, gpa_t addr,
+int kvm_io_bus_write(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
                      int len, const void *val)
 {
         int i;
+        struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]);
         for (i = 0; i < bus->dev_count; i++)
                 if (!kvm_iodevice_write(bus->devs[i], addr, len, val))
                         return 0;
@@ -1977,59 +1985,71 @@ int kvm_io_bus_write(struct kvm_io_bus *bus, gpa_t addr,
 }
 
 /* kvm_io_bus_read - called under kvm->slots_lock */
-int kvm_io_bus_read(struct kvm_io_bus *bus, gpa_t addr, int len, void *val)
+int kvm_io_bus_read(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
+                    int len, void *val)
 {
         int i;
+        struct kvm_io_bus *bus = rcu_dereference(kvm->buses[bus_idx]);
+
         for (i = 0; i < bus->dev_count; i++)
                 if (!kvm_iodevice_read(bus->devs[i], addr, len, val))
                         return 0;
         return -EOPNOTSUPP;
 }
 
-int kvm_io_bus_register_dev(struct kvm *kvm, struct kvm_io_bus *bus,
-                             struct kvm_io_device *dev)
+/* Caller must have write lock on slots_lock. */
+int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+                            struct kvm_io_device *dev)
 {
-        int ret;
-
-        down_write(&kvm->slots_lock);
-        ret = __kvm_io_bus_register_dev(bus, dev);
-        up_write(&kvm->slots_lock);
+        struct kvm_io_bus *new_bus, *bus;
 
-        return ret;
-}
-
-/* An unlocked version. Caller must have write lock on slots_lock. */
-int __kvm_io_bus_register_dev(struct kvm_io_bus *bus,
-                              struct kvm_io_device *dev)
-{
+        bus = kvm->buses[bus_idx];
         if (bus->dev_count > NR_IOBUS_DEVS-1)
                 return -ENOSPC;
 
-        bus->devs[bus->dev_count++] = dev;
+        new_bus = kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL);
+        if (!new_bus)
+                return -ENOMEM;
+        memcpy(new_bus, bus, sizeof(struct kvm_io_bus));
+        new_bus->devs[new_bus->dev_count++] = dev;
+        rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
+        synchronize_srcu_expedited(&kvm->srcu);
+        kfree(bus);
 
         return 0;
 }
 
-void kvm_io_bus_unregister_dev(struct kvm *kvm,
-                               struct kvm_io_bus *bus,
-                               struct kvm_io_device *dev)
+/* Caller must have write lock on slots_lock. */
+int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+                              struct kvm_io_device *dev)
 {
-        down_write(&kvm->slots_lock);
-        __kvm_io_bus_unregister_dev(bus, dev);
-        up_write(&kvm->slots_lock);
-}
+        int i, r;
+        struct kvm_io_bus *new_bus, *bus;
 
-/* An unlocked version. Caller must have write lock on slots_lock. */
-void __kvm_io_bus_unregister_dev(struct kvm_io_bus *bus,
-                                 struct kvm_io_device *dev)
-{
-        int i;
+        new_bus = kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL);
+        if (!new_bus)
+                return -ENOMEM;
 
-        for (i = 0; i < bus->dev_count; i++)
-                if (bus->devs[i] == dev) {
-                        bus->devs[i] = bus->devs[--bus->dev_count];
+        bus = kvm->buses[bus_idx];
+        memcpy(new_bus, bus, sizeof(struct kvm_io_bus));
+
+        r = -ENOENT;
+        for (i = 0; i < new_bus->dev_count; i++)
+                if (new_bus->devs[i] == dev) {
+                        r = 0;
+                        new_bus->devs[i] = new_bus->devs[--new_bus->dev_count];
                         break;
                 }
+
+        if (r) {
+                kfree(new_bus);
+                return r;
+        }
+
+        rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
+        synchronize_srcu_expedited(&kvm->srcu);
+        kfree(bus);
+        return r;
 }
 
 static struct notifier_block kvm_cpu_notifier = {