1 files changed, 60 insertions, 71 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index fc8487564d1f..a6ec206f36ba 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -24,10 +24,19 @@ static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
 static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
 				   gpa_t addr, int len)
 {
-	struct kvm_coalesced_mmio_zone *zone;
+	/* is it in a batchable area ?
+	 * (addr,len) is fully included in
+	 * (zone->addr, zone->size)
+	 */
+
+	return (dev->zone.addr <= addr &&
+		addr + len <= dev->zone.addr + dev->zone.size);
+}
+
+static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev)
+{
 	struct kvm_coalesced_mmio_ring *ring;
 	unsigned avail;
-	int i;
 
 	/* Are we able to batch it ? */
 
@@ -37,25 +46,12 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
 	 */
 	ring = dev->kvm->coalesced_mmio_ring;
 	avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
-	if (avail < KVM_MAX_VCPUS) {
+	if (avail == 0) {
 		/* full */
 		return 0;
 	}
 
-	/* is it in a batchable area ? */
-
-	for (i = 0; i < dev->nb_zones; i++) {
-		zone = &dev->zone[i];
-
-		/* (addr,len) is fully included in
-		 * (zone->addr, zone->size)
-		 */
-
-		if (zone->addr <= addr &&
-		    addr + len <= zone->addr + zone->size)
-			return 1;
-	}
-	return 0;
+	return 1;
 }
 
 static int coalesced_mmio_write(struct kvm_io_device *this,
@@ -63,10 +59,16 @@ static int coalesced_mmio_write(struct kvm_io_device *this,
 {
 	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;
 
-	spin_lock(&dev->lock);
+	spin_lock(&dev->kvm->ring_lock);
+
+	if (!coalesced_mmio_has_room(dev)) {
+		spin_unlock(&dev->kvm->ring_lock);
+		return -EOPNOTSUPP;
+	}
 
 	/* copy data in first free entry of the ring */
 
@@ -75,7 +77,7 @@ static int 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);
+	spin_unlock(&dev->kvm->ring_lock);
 	return 0;
 }
 
@@ -83,6 +85,8 @@ static void coalesced_mmio_destructor(struct kvm_io_device *this)
 {
 	struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
 
+	list_del(&dev->list);
+
 	kfree(dev);
 }
 
@@ -93,7 +97,6 @@ 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;
 
@@ -101,31 +104,18 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
 	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)
-		goto out_free_page;
-	spin_lock_init(&dev->lock);
-	kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
-	dev->kvm = kvm;
-	kvm->coalesced_mmio_dev = dev;
 
-	mutex_lock(&kvm->slots_lock);
-	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &dev->dev);
-	mutex_unlock(&kvm->slots_lock);
-	if (ret < 0)
-		goto out_free_dev;
+	ret = 0;
+	kvm->coalesced_mmio_ring = page_address(page);
 
-	return ret;
+	/*
+	 * We're using this spinlock to sync access to the coalesced ring.
+	 * The list doesn't need it's own lock since device registration and
+	 * unregistration should only happen when kvm->slots_lock is held.
+	 */
+	spin_lock_init(&kvm->ring_lock);
+	INIT_LIST_HEAD(&kvm->coalesced_zones);
 
-out_free_dev:
-	kvm->coalesced_mmio_dev = NULL;
-	kfree(dev);
-out_free_page:
-	kvm->coalesced_mmio_ring = NULL;
-	__free_page(page);
 out_err:
 	return ret;
 }
@@ -139,51 +129,50 @@ void kvm_coalesced_mmio_free(struct kvm *kvm)
 int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
 					 struct kvm_coalesced_mmio_zone *zone)
 {
-	struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
+	int ret;
+	struct kvm_coalesced_mmio_dev *dev;
 
-	if (dev == NULL)
-		return -ENXIO;
+	dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
+	dev->kvm = kvm;
+	dev->zone = *zone;
 
 	mutex_lock(&kvm->slots_lock);
-	if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
-		mutex_unlock(&kvm->slots_lock);
-		return -ENOBUFS;
-	}
+	ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, zone->addr,
+				      zone->size, &dev->dev);
+	if (ret < 0)
+		goto out_free_dev;
+	list_add_tail(&dev->list, &kvm->coalesced_zones);
+	mutex_unlock(&kvm->slots_lock);
 
-	dev->zone[dev->nb_zones] = *zone;
-	dev->nb_zones++;
+	return ret;
 
+out_free_dev:
 	mutex_unlock(&kvm->slots_lock);
+
+	kfree(dev);
+
+	if (dev == NULL)
+		return -ENXIO;
+
 	return 0;
 }
 
 int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
 					   struct kvm_coalesced_mmio_zone *zone)
 {
-	int i;
-	struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
-	struct kvm_coalesced_mmio_zone *z;
-
-	if (dev == NULL)
-		return -ENXIO;
+	struct kvm_coalesced_mmio_dev *dev, *tmp;
 
 	mutex_lock(&kvm->slots_lock);
 
-	i = dev->nb_zones;
-	while (i) {
-		z = &dev->zone[i - 1];
-
-		/* unregister all zones
-		 * included in (zone->addr, zone->size)
-		 */
-
-		if (zone->addr <= z->addr &&
-		    z->addr + z->size <= zone->addr + zone->size) {
-			dev->nb_zones--;
-			*z = dev->zone[dev->nb_zones];
+	list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list)
+		if (coalesced_mmio_in_range(dev, zone->addr, zone->size)) {
+			kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &dev->dev);
+			kvm_iodevice_destructor(&dev->dev);
 		}
-		i--;
-	}
 
 	mutex_unlock(&kvm->slots_lock);