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Subject[PATCH 36/48] KVM: move coalesced_mmio locking to its own device
Date
From: Marcelo Tosatti <mtosatti@redhat.com>

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

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
virt/kvm/coalesced_mmio.c | 10 ++++------
virt/kvm/coalesced_mmio.h | 1 +
2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 7549068..397f419 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -31,10 +31,6 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
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 +39,7 @@ 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;
}
@@ -70,7 +66,7 @@ static void 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;

- /* 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 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);
}

static void coalesced_mmio_destructor(struct kvm_io_device *this)
@@ -101,6 +98,7 @@ int kvm_coalesced_mmio_init(struct kvm *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;
diff --git a/virt/kvm/coalesced_mmio.h b/virt/kvm/coalesced_mmio.h
index 5ac0ec6..4b49f27 100644
--- a/virt/kvm/coalesced_mmio.h
+++ b/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];
};
--
1.6.3.3


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