[patch 2/4] KVM: move coalesced_mmio locking to its own device

Marcelo Tosatti
2009-06-04T18:12:48Z

[-- Attachment #1: coalesced-mmio-lock --]
[-- Type: text/plain, Size: 1890 bytes --]

Move coalesced_mmio locking to its own device, instead of relying on
kvm->lock.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

Index: kvm/virt/kvm/coalesced_mmio.c
===================================================================
--- kvm.orig/virt/kvm/coalesced_mmio.c
+++ kvm/virt/kvm/coalesced_mmio.c
@@ -31,10 +31,6 @@ static int coalesced_mmio_in_range(struc
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
@@ -70,7 +66,7 @@ static void coalesced_mmio_write(struct
struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;

- /* 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 +75,7 @@ static void coalesced_mmio_write(struct
memcpy(ring->coalesced_mmio[ring->last].data, val, len);
smp_wmb();
ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
+ spin_unlock(&dev->lock);
}

static void coalesced_mmio_destructor(struct kvm_io_device *this)
@@ -101,6 +98,7 @@ int kvm_coalesced_mmio_init(struct kvm *
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;
Index: kvm/virt/kvm/coalesced_mmio.h
===================================================================
--- kvm.orig/virt/kvm/coalesced_mmio.h
+++ kvm/virt/kvm/coalesced_mmio.h
@@ -12,6 +12,7 @@
struct kvm_coalesced_mmio_dev {
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];
};

--