Merge remote-tracking branch 'aosp/android-4.4' into kernel-4.4

[android-x86/kernel.git] / virt / kvm / kvm_main.c

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 336ed26..cb092bd 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -654,8 +654,11 @@ static void kvm_destroy_vm(struct kvm *kvm)
        list_del(&kvm->vm_list);
        spin_unlock(&kvm_lock);
        kvm_free_irq_routing(kvm);
-       for (i = 0; i < KVM_NR_BUSES; i++)
-               kvm_io_bus_destroy(kvm->buses[i]);
+       for (i = 0; i < KVM_NR_BUSES; i++) {
+               if (kvm->buses[i])
+                       kvm_io_bus_destroy(kvm->buses[i]);
+               kvm->buses[i] = NULL;
+       }
        kvm_coalesced_mmio_free(kvm);
 #if defined(CONFIG_MMU_NOTIFIER) && defined(KVM_ARCH_WANT_MMU_NOTIFIER)
        mmu_notifier_unregister(&kvm->mmu_notifier, kvm->mm);
@@ -3271,6 +3274,8 @@ int kvm_io_bus_write(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
        };
 
        bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+       if (!bus)
+               return -ENOMEM;
        r = __kvm_io_bus_write(vcpu, bus, &range, val);
        return r < 0 ? r : 0;
 }
@@ -3288,6 +3293,8 @@ int kvm_io_bus_write_cookie(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx,
        };
 
        bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+       if (!bus)
+               return -ENOMEM;
 
        /* First try the device referenced by cookie. */
        if ((cookie >= 0) && (cookie < bus->dev_count) &&
@@ -3338,6 +3345,8 @@ int kvm_io_bus_read(struct kvm_vcpu *vcpu, enum kvm_bus bus_idx, gpa_t addr,
        };
 
        bus = srcu_dereference(vcpu->kvm->buses[bus_idx], &vcpu->kvm->srcu);
+       if (!bus)
+               return -ENOMEM;
        r = __kvm_io_bus_read(vcpu, bus, &range, val);
        return r < 0 ? r : 0;
 }
@@ -3350,6 +3359,9 @@ 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];
+       if (!bus)
+               return -ENOMEM;
+
        /* exclude ioeventfd which is limited by maximum fd */
        if (bus->dev_count - bus->ioeventfd_count > NR_IOBUS_DEVS - 1)
                return -ENOSPC;
@@ -3369,37 +3381,41 @@ int kvm_io_bus_register_dev(struct kvm *kvm, enum kvm_bus bus_idx, gpa_t addr,
 }
 
 /* Caller must hold slots_lock. */
-int kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
-                             struct kvm_io_device *dev)
+void kvm_io_bus_unregister_dev(struct kvm *kvm, enum kvm_bus bus_idx,
+                              struct kvm_io_device *dev)
 {
-       int i, r;
+       int i;
        struct kvm_io_bus *new_bus, *bus;
 
        bus = kvm->buses[bus_idx];
-       r = -ENOENT;
+       if (!bus)
+               return;
+
        for (i = 0; i < bus->dev_count; i++)
                if (bus->range[i].dev == dev) {
-                       r = 0;
                        break;
                }
 
-       if (r)
-               return r;
+       if (i == bus->dev_count)
+               return;
 
        new_bus = kmalloc(sizeof(*bus) + ((bus->dev_count - 1) *
                          sizeof(struct kvm_io_range)), GFP_KERNEL);
-       if (!new_bus)
-               return -ENOMEM;
+       if (!new_bus)  {
+               pr_err("kvm: failed to shrink bus, removing it completely\n");
+               goto broken;
+       }
 
        memcpy(new_bus, bus, sizeof(*bus) + i * sizeof(struct kvm_io_range));
        new_bus->dev_count--;
        memcpy(new_bus->range + i, bus->range + i + 1,
               (new_bus->dev_count - i) * sizeof(struct kvm_io_range));
 
+broken:
        rcu_assign_pointer(kvm->buses[bus_idx], new_bus);
        synchronize_srcu_expedited(&kvm->srcu);
        kfree(bus);
-       return r;
+       return;
 }
 
 static struct notifier_block kvm_cpu_notifier = {