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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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