KVM: avoid using rcu_dereference_protected
[linux-2.6-microblaze.git] / virt / kvm / kvm_main.c
index 19f0ecb..15252d7 100644 (file)
@@ -130,6 +130,12 @@ EXPORT_SYMBOL_GPL(kvm_rebooting);
 
 static bool largepages_enabled = true;
 
+#define KVM_EVENT_CREATE_VM 0
+#define KVM_EVENT_DESTROY_VM 1
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm);
+static unsigned long long kvm_createvm_count;
+static unsigned long long kvm_active_vms;
+
 bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
 {
        if (pfn_valid(pfn))
@@ -187,12 +193,23 @@ static void ack_flush(void *_completed)
 {
 }
 
+static inline bool kvm_kick_many_cpus(const struct cpumask *cpus, bool wait)
+{
+       if (unlikely(!cpus))
+               cpus = cpu_online_mask;
+
+       if (cpumask_empty(cpus))
+               return false;
+
+       smp_call_function_many(cpus, ack_flush, NULL, wait);
+       return true;
+}
+
 bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 {
        int i, cpu, me;
        cpumask_var_t cpus;
-       bool called = true;
-       bool wait = req & KVM_REQUEST_WAIT;
+       bool called;
        struct kvm_vcpu *vcpu;
 
        zalloc_cpumask_var(&cpus, GFP_ATOMIC);
@@ -207,14 +224,9 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
 
                if (cpus != NULL && cpu != -1 && cpu != me &&
                    kvm_request_needs_ipi(vcpu, req))
-                       cpumask_set_cpu(cpu, cpus);
+                       __cpumask_set_cpu(cpu, cpus);
        }
-       if (unlikely(cpus == NULL))
-               smp_call_function_many(cpu_online_mask, ack_flush, NULL, wait);
-       else if (!cpumask_empty(cpus))
-               smp_call_function_many(cpus, ack_flush, NULL, wait);
-       else
-               called = false;
+       called = kvm_kick_many_cpus(cpus, !!(req & KVM_REQUEST_WAIT));
        put_cpu();
        free_cpumask_var(cpus);
        return called;
@@ -293,7 +305,12 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init);
 
 void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
 {
-       put_pid(vcpu->pid);
+       /*
+        * no need for rcu_read_lock as VCPU_RUN is the only place that
+        * will change the vcpu->pid pointer and on uninit all file
+        * descriptors are already gone.
+        */
+       put_pid(rcu_dereference_protected(vcpu->pid, 1));
        kvm_arch_vcpu_uninit(vcpu);
        free_page((unsigned long)vcpu->run);
 }
@@ -674,8 +691,8 @@ static struct kvm *kvm_create_vm(unsigned long type)
        if (init_srcu_struct(&kvm->irq_srcu))
                goto out_err_no_irq_srcu;
        for (i = 0; i < KVM_NR_BUSES; i++) {
-               kvm->buses[i] = kzalloc(sizeof(struct kvm_io_bus),
-                                       GFP_KERNEL);
+               rcu_assign_pointer(kvm->buses[i],
+                       kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL));
                if (!kvm->buses[i])
                        goto out_err;
        }
@@ -700,9 +717,9 @@ out_err_no_srcu:
        hardware_disable_all();
 out_err_no_disable:
        for (i = 0; i < KVM_NR_BUSES; i++)
-               kfree(kvm->buses[i]);
+               kfree(kvm_get_bus(kvm, i));
        for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
-               kvm_free_memslots(kvm, kvm->memslots[i]);
+               kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
        kvm_arch_free_vm(kvm);
        mmdrop(current->mm);
        return ERR_PTR(r);
@@ -728,6 +745,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
        int i;
        struct mm_struct *mm = kvm->mm;
 
+       kvm_uevent_notify_change(KVM_EVENT_DESTROY_VM, kvm);
        kvm_destroy_vm_debugfs(kvm);
        kvm_arch_sync_events(kvm);
        spin_lock(&kvm_lock);
@@ -735,8 +753,10 @@ static void kvm_destroy_vm(struct kvm *kvm)
        spin_unlock(&kvm_lock);
        kvm_free_irq_routing(kvm);
        for (i = 0; i < KVM_NR_BUSES; i++) {
-               if (kvm->buses[i])
-                       kvm_io_bus_destroy(kvm->buses[i]);
+               struct kvm_io_bus *bus = kvm_get_bus(kvm, i);
+
+               if (bus)
+                       kvm_io_bus_destroy(bus);
                kvm->buses[i] = NULL;
        }
        kvm_coalesced_mmio_free(kvm);
@@ -748,7 +768,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
        kvm_arch_destroy_vm(kvm);
        kvm_destroy_devices(kvm);
        for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
-               kvm_free_memslots(kvm, kvm->memslots[i]);
+               kvm_free_memslots(kvm, __kvm_memslots(kvm, i));
        cleanup_srcu_struct(&kvm->irq_srcu);
        cleanup_srcu_struct(&kvm->srcu);
        kvm_arch_free_vm(kvm);
@@ -2551,13 +2571,14 @@ static long kvm_vcpu_ioctl(struct file *filp,
        if (r)
                return r;
        switch (ioctl) {
-       case KVM_RUN:
+       case KVM_RUN: {
+               struct pid *oldpid;
                r = -EINVAL;
                if (arg)
                        goto out;
-               if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) {
+               oldpid = rcu_access_pointer(vcpu->pid);
+               if (unlikely(oldpid != current->pids[PIDTYPE_PID].pid)) {
                        /* The thread running this VCPU changed. */
-                       struct pid *oldpid = vcpu->pid;
                        struct pid *newpid = get_task_pid(current, PIDTYPE_PID);
 
                        rcu_assign_pointer(vcpu->pid, newpid);
@@ -2568,6 +2589,7 @@ static long kvm_vcpu_ioctl(struct file *filp,
                r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run);
                trace_kvm_userspace_exit(vcpu->run->exit_reason, r);
                break;
+       }
        case KVM_GET_REGS: {
                struct kvm_regs *kvm_regs;
 
@@ -3202,6 +3224,7 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
                fput(file);
                return -ENOMEM;
        }
+       kvm_uevent_notify_change(KVM_EVENT_CREATE_VM, kvm);
 
        fd_install(r, file);
        return r;
@@ -3563,7 +3586,7 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
 {
        struct kvm_io_bus *new_bus, *bus;
 
-       bus = kvm->buses[bus_idx];
+       bus = kvm_get_bus(kvm, bus_idx);
        if (!bus)
                return -ENOMEM;
 
@@ -3592,7 +3615,7 @@ void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
        int i;
        struct kvm_io_bus *new_bus, *bus;
 
-       bus = kvm->buses[bus_idx];
+       bus = kvm_get_bus(kvm, bus_idx);
        if (!bus)
                return;
 
@@ -3854,6 +3877,56 @@ static const struct file_operations *stat_fops[] = {
        [KVM_STAT_VM]   = &vm_stat_fops,
 };
 
+static void kvm_uevent_notify_change(unsigned int type, struct kvm *kvm)
+{
+       struct kobj_uevent_env *env;
+       unsigned long long created, active;
+
+       if (!kvm_dev.this_device || !kvm)
+               return;
+
+       spin_lock(&kvm_lock);
+       if (type == KVM_EVENT_CREATE_VM) {
+               kvm_createvm_count++;
+               kvm_active_vms++;
+       } else if (type == KVM_EVENT_DESTROY_VM) {
+               kvm_active_vms--;
+       }
+       created = kvm_createvm_count;
+       active = kvm_active_vms;
+       spin_unlock(&kvm_lock);
+
+       env = kzalloc(sizeof(*env), GFP_KERNEL);
+       if (!env)
+               return;
+
+       add_uevent_var(env, "CREATED=%llu", created);
+       add_uevent_var(env, "COUNT=%llu", active);
+
+       if (type == KVM_EVENT_CREATE_VM) {
+               add_uevent_var(env, "EVENT=create");
+               kvm->userspace_pid = task_pid_nr(current);
+       } else if (type == KVM_EVENT_DESTROY_VM) {
+               add_uevent_var(env, "EVENT=destroy");
+       }
+       add_uevent_var(env, "PID=%d", kvm->userspace_pid);
+
+       if (kvm->debugfs_dentry) {
+               char *tmp, *p = kmalloc(PATH_MAX, GFP_KERNEL);
+
+               if (p) {
+                       tmp = dentry_path_raw(kvm->debugfs_dentry, p, PATH_MAX);
+                       if (!IS_ERR(tmp))
+                               add_uevent_var(env, "STATS_PATH=%s", tmp);
+                       kfree(p);
+               }
+       }
+       /* no need for checks, since we are adding at most only 5 keys */
+       env->envp[env->envp_idx++] = NULL;
+       kobject_uevent_env(&kvm_dev.this_device->kobj, KOBJ_CHANGE, env->envp);
+       kfree(env);
+}
+
 static int kvm_init_debug(void)
 {
        int r = -EEXIST;