Merge tag 'trace-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...

[linux-2.6-microblaze.git] / virt / kvm / coalesced_mmio.c

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 62bd908..f08f5e8 100644 (file)
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -174,21 +174,36 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
                                           struct kvm_coalesced_mmio_zone *zone)
 {
        struct kvm_coalesced_mmio_dev *dev, *tmp;
+       int r;
 
        if (zone->pio != 1 && zone->pio != 0)
                return -EINVAL;
 
        mutex_lock(&kvm->slots_lock);
 
-       list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list)
+       list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list) {
                if (zone->pio == dev->zone.pio &&
                    coalesced_mmio_in_range(dev, zone->addr, zone->size)) {
-                       kvm_io_bus_unregister_dev(kvm,
+                       r = kvm_io_bus_unregister_dev(kvm,
                                zone->pio ? KVM_PIO_BUS : KVM_MMIO_BUS, &dev->dev);
                        kvm_iodevice_destructor(&dev->dev);
+
+                       /*
+                        * On failure, unregister destroys all devices on the
+                        * bus _except_ the target device, i.e. coalesced_zones
+                        * has been modified.  No need to restart the walk as
+                        * there aren't any zones left.
+                        */
+                       if (r)
+                               break;
                }
+       }
 
        mutex_unlock(&kvm->slots_lock);
 
+       /*
+        * Ignore the result of kvm_io_bus_unregister_dev(), from userspace's
+        * perspective, the coalesced MMIO is most definitely unregistered.
+        */
        return 0;
 }