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authorIzik Eidus <izike@qumranet.com>2008-03-30 09:01:25 -0400
committerAvi Kivity <avi@qumranet.com>2008-04-27 05:00:56 -0400
commitd39f13b0da7fa7f705fbe6c80995205d0380bc7a (patch)
treefebc1458c6225c70ca4c435047acf279fd77b019 /virt/kvm
parent9c20456a32ce9e82ccda55e12c10016b181d85e5 (diff)
KVM: add vm refcounting
the main purpose of adding this functions is the abilaty to release the spinlock that protect the kvm list while still be able to do operations on a specific kvm in a safe way. Signed-off-by: Izik Eidus <izike@qumranet.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'virt/kvm')
-rw-r--r--virt/kvm/kvm_main.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 41d4b6519136..93ed78b015c0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -193,6 +193,7 @@ static struct kvm *kvm_create_vm(void)
193 mutex_init(&kvm->lock); 193 mutex_init(&kvm->lock);
194 kvm_io_bus_init(&kvm->mmio_bus); 194 kvm_io_bus_init(&kvm->mmio_bus);
195 init_rwsem(&kvm->slots_lock); 195 init_rwsem(&kvm->slots_lock);
196 atomic_set(&kvm->users_count, 1);
196 spin_lock(&kvm_lock); 197 spin_lock(&kvm_lock);
197 list_add(&kvm->vm_list, &vm_list); 198 list_add(&kvm->vm_list, &vm_list);
198 spin_unlock(&kvm_lock); 199 spin_unlock(&kvm_lock);
@@ -242,11 +243,25 @@ static void kvm_destroy_vm(struct kvm *kvm)
242 mmdrop(mm); 243 mmdrop(mm);
243} 244}
244 245
246void kvm_get_kvm(struct kvm *kvm)
247{
248 atomic_inc(&kvm->users_count);
249}
250EXPORT_SYMBOL_GPL(kvm_get_kvm);
251
252void kvm_put_kvm(struct kvm *kvm)
253{
254 if (atomic_dec_and_test(&kvm->users_count))
255 kvm_destroy_vm(kvm);
256}
257EXPORT_SYMBOL_GPL(kvm_put_kvm);
258
259
245static int kvm_vm_release(struct inode *inode, struct file *filp) 260static int kvm_vm_release(struct inode *inode, struct file *filp)
246{ 261{
247 struct kvm *kvm = filp->private_data; 262 struct kvm *kvm = filp->private_data;
248 263
249 kvm_destroy_vm(kvm); 264 kvm_put_kvm(kvm);
250 return 0; 265 return 0;
251} 266}
252 267