KVM: convert io_bus to SRCU

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index b2e4d16..d0ad538 100644 (file)
--- 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 15578f1..4b433de 100644 (file)
--- 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 d057c0c..b7d145b 100644 (file)
--- 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 28127c9..9b42673 100644 (file)
--- 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 20941c0..5e9cb90 100644 (file)
--- 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 d68e6c6..a736a93 100644 (file)
--- 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 a9d3fc6..315a586 100644 (file)
--- 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 38a2d20..f326a6f 100644 (file)
--- 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 c680f7b..659bc12 100644 (file)
--- 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 = {