On 07/19/2011 01:31 PM, Sasha Levin wrote:
This patch changes coalesced mmio to create one mmio device per
zone instead of handling all zones in one device.
Doing so enables us to take advantage of existing locking and prevents
a race condition between coalesced mmio registration/unregistration
and lookups.
@@ -63,7 +63,7 @@ extern struct kmem_cache *kvm_vcpu_cache;
*/
struct kvm_io_bus {
int dev_count;
-#define NR_IOBUS_DEVS 200
+#define NR_IOBUS_DEVS 300
struct kvm_io_device *devs[NR_IOBUS_DEVS];
};
This means that a lot of non-coalesced-mmio users can squeeze out
coalesced-mmio. I don't know if it's really worthwhile, but the 100
coalesced mmio slots should be reserved so we are guaranteed they are
available.
@@ -95,6 +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);
}
No lock?
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;
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(dev,&kvm->coalesced_zones.items, 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--;
- }
No lock?
struct kvm_coalesced_mmio_dev {
+ struct list_head list;
struct kvm_io_device dev;
struct kvm *kvm;
- spinlock_t lock;
- int nb_zones;
- struct kvm_coalesced_mmio_zone zone[KVM_COALESCED_MMIO_ZONE_MAX];
+ struct kvm_coalesced_mmio_zone zone;
};
Why a list instead of a linear array?
--
error compiling committee.c: too many arguments to function
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