KVM: Use kmem cache for allocating vcpus

Avi wants the allocations of vcpus centralized again.  The easiest way
is to add a "size" arg to kvm_init_arch, and expose the thus-prepared
cache to the modules.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 4bbd89e03324..4166a08ce500 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -53,6 +53,8 @@ static LIST_HEAD(vm_list);
 static cpumask_t cpus_hardware_enabled;
 
 struct kvm_arch_ops *kvm_arch_ops;
+struct kmem_cache *kvm_vcpu_cache;
+EXPORT_SYMBOL_GPL(kvm_vcpu_cache);
 
 static __read_mostly struct preempt_ops kvm_preempt_ops;
 
@@ -3104,7 +3106,8 @@ static void kvm_sched_out(struct preempt_notifier *pn,
         kvm_arch_ops->vcpu_put(vcpu);
 }
 
-int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
+int kvm_init_arch(struct kvm_arch_ops *ops, unsigned int vcpu_size,
+                  struct module *module)
 {
         int r;
 
@@ -3142,6 +3145,14 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
         if (r)
                 goto out_free_3;
 
+        /* A kmem cache lets us meet the alignment requirements of fx_save. */
+        kvm_vcpu_cache = kmem_cache_create("kvm_vcpu", vcpu_size,
+                                           __alignof__(struct kvm_vcpu), 0, 0);
+        if (!kvm_vcpu_cache) {
+                r = -ENOMEM;
+                goto out_free_4;
+        }
+
         kvm_chardev_ops.owner = module;
 
         r = misc_register(&kvm_dev);
@@ -3156,6 +3167,8 @@ int kvm_init_arch(struct kvm_arch_ops *ops, struct module *module)
         return r;
 
 out_free:
+        kmem_cache_destroy(kvm_vcpu_cache);
+out_free_4:
         sysdev_unregister(&kvm_sysdev);
 out_free_3:
         sysdev_class_unregister(&kvm_sysdev_class);
@@ -3173,6 +3186,7 @@ out:
 void kvm_exit_arch(void)
 {
         misc_deregister(&kvm_dev);
+        kmem_cache_destroy(kvm_vcpu_cache);
         sysdev_unregister(&kvm_sysdev);
         sysdev_class_unregister(&kvm_sysdev_class);
         unregister_reboot_notifier(&kvm_reboot_notifier);