KVM: correct error-handling code

[safe/jmp/linux-2.6] / virt / kvm / coalesced_mmio.c

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 7549068..04d69cd 100644 (file)
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -19,22 +19,14 @@ static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
        return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
 }
 
-static int coalesced_mmio_in_range(struct kvm_io_device *this,
-                                  gpa_t addr, int len, int is_write)
+static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
+                                  gpa_t addr, int len)
 {
-       struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
        struct kvm_coalesced_mmio_zone *zone;
        struct kvm_coalesced_mmio_ring *ring;
        unsigned avail;
        int i;
 
-       if (!is_write)
-               return 0;
-
-       /* kvm->lock is taken by the caller and must be not released before
-         * dev.read/write
-         */
-
        /* Are we able to batch it ? */
 
        /* last is the first free entry
@@ -43,7 +35,7 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
         */
        ring = dev->kvm->coalesced_mmio_ring;
        avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
-       if (avail < 1) {
+       if (avail < KVM_MAX_VCPUS) {
                /* full */
                return 0;
        }
@@ -64,13 +56,15 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
        return 0;
 }
 
-static void coalesced_mmio_write(struct kvm_io_device *this,
-                                gpa_t addr, int len, const void *val)
+static int coalesced_mmio_write(struct kvm_io_device *this,
+                               gpa_t addr, int len, const void *val)
 {
        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
        struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
+       if (!coalesced_mmio_in_range(dev, addr, len))
+               return -EOPNOTSUPP;
 
-       /* kvm->lock must be taken by caller before call to in_range()*/
+       spin_lock(&dev->lock);
 
        /* copy data in first free entry of the ring */
 
@@ -79,6 +73,8 @@ static void coalesced_mmio_write(struct kvm_io_device *this,
        memcpy(ring->coalesced_mmio[ring->last].data, val, len);
        smp_wmb();
        ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
+       spin_unlock(&dev->lock);
+       return 0;
 }
 
 static void coalesced_mmio_destructor(struct kvm_io_device *this)
@@ -90,23 +86,27 @@ static void coalesced_mmio_destructor(struct kvm_io_device *this)
 
 static const struct kvm_io_device_ops coalesced_mmio_ops = {
        .write      = coalesced_mmio_write,
-       .in_range   = coalesced_mmio_in_range,
        .destructor = coalesced_mmio_destructor,
 };
 
 int kvm_coalesced_mmio_init(struct kvm *kvm)
 {
        struct kvm_coalesced_mmio_dev *dev;
+       int ret;
 
        dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
+       spin_lock_init(&dev->lock);
        kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
        dev->kvm = kvm;
        kvm->coalesced_mmio_dev = dev;
-       kvm_io_bus_register_dev(&kvm->mmio_bus, &dev->dev);
 
-       return 0;
+       ret = kvm_io_bus_register_dev(kvm, &kvm->mmio_bus, &dev->dev);
+       if (ret < 0)
+               kfree(dev);
+
+       return ret;
 }
 
 int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
@@ -117,16 +117,16 @@ int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
        if (dev == NULL)
                return -EINVAL;
 
-       mutex_lock(&kvm->lock);
+       down_write(&kvm->slots_lock);
        if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
-               mutex_unlock(&kvm->lock);
+               up_write(&kvm->slots_lock);
                return -ENOBUFS;
        }
 
        dev->zone[dev->nb_zones] = *zone;
        dev->nb_zones++;
 
-       mutex_unlock(&kvm->lock);
+       up_write(&kvm->slots_lock);
        return 0;
 }
 
@@ -140,7 +140,7 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
        if (dev == NULL)
                return -EINVAL;
 
-       mutex_lock(&kvm->lock);
+       down_write(&kvm->slots_lock);
 
        i = dev->nb_zones;
        while(i) {
@@ -158,7 +158,7 @@ int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
                i--;
        }
 
-       mutex_unlock(&kvm->lock);
+       up_write(&kvm->slots_lock);
 
        return 0;
 }