KVM: Make coalesced mmio use a device per zone

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.

Suggested-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index eabb21a30c34..ff4d4062af9d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -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];
 };
 
@@ -256,8 +256,9 @@ struct kvm {
         struct kvm_arch arch;
         atomic_t users_count;
 #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
-        struct kvm_coalesced_mmio_dev *coalesced_mmio_dev;
         struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
+        spinlock_t ring_lock;
+        struct list_head coalesced_zones;
 #endif
 
         struct mutex irq_lock;