KVM: convert io_bus to SRCU
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c680f7b..659bc12 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -85,6 +85,8 @@
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 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 @@
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 @@
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_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 @@
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 @@
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 @@
.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 @@
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 @@
}
/* 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;
+ struct kvm_io_bus *new_bus, *bus;
- down_write(&kvm->slots_lock);
- ret = __kvm_io_bus_register_dev(bus, dev);
- up_write(&kvm->slots_lock);
-
- 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 = {