KVM: Simplify coalesced mmio initialization

- add destructor function
- move related allocation into constructor
- add stubs for !CONFIG_KVM_MMIO

Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 23 insertions, 2 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 04d69cd7049b..d68e6c68e0ff 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -92,11 +92,19 @@ static const struct kvm_io_device_ops coalesced_mmio_ops = {
 int kvm_coalesced_mmio_init(struct kvm *kvm)
 {
         struct kvm_coalesced_mmio_dev *dev;
+        struct page *page;
         int ret;
 
+        ret = -ENOMEM;
+        page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+        if (!page)
+                goto out_err;
+        kvm->coalesced_mmio_ring = page_address(page);
+
+        ret = -ENOMEM;
         dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
         if (!dev)
-                return -ENOMEM;
+                goto out_free_page;
         spin_lock_init(&dev->lock);
         kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
         dev->kvm = kvm;
@@ -104,11 +112,24 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
 
         ret = kvm_io_bus_register_dev(kvm, &kvm->mmio_bus, &dev->dev);
         if (ret < 0)
-                kfree(dev);
+                goto out_free_dev;
+
+        return ret;
 
+out_free_dev:
+        kfree(dev);
+out_free_page:
+        __free_page(page);
+out_err:
         return ret;
 }
 
+void kvm_coalesced_mmio_free(struct kvm *kvm)
+{
+        if (kvm->coalesced_mmio_ring)
+                free_page((unsigned long)kvm->coalesced_mmio_ring);
+}
+
 int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
                                          struct kvm_coalesced_mmio_zone *zone)
 {