1 files changed, 156 insertions, 0 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
new file mode 100644
index 000000000000..5ae620d32fac
--- /dev/null
+++ b/virt/kvm/coalesced_mmio.c
@@ -0,0 +1,156 @@
+/*
+ * KVM coalesced MMIO
+ *
+ * Copyright (c) 2008 Bull S.A.S.
+ *
+ *  Author: Laurent Vivier <Laurent.Vivier@bull.net>
+ *
+ */
+
+#include "iodev.h"
+
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+
+#include "coalesced_mmio.h"
+
+static int coalesced_mmio_in_range(struct kvm_io_device *this,
+                                   gpa_t addr, int len, int is_write)
+{
+        struct kvm_coalesced_mmio_dev *dev =
+                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_zone *zone;
+        int next;
+        int i;
+
+        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
+         * check if we don't meet the first used entry
+         * there is always one unused entry in the buffer
+         */
+
+        next = (dev->kvm->coalesced_mmio_ring->last + 1) %
+                                                        KVM_COALESCED_MMIO_MAX;
+        if (next == dev->kvm->coalesced_mmio_ring->first) {
+                /* full */
+                return 0;
+        }
+
+        /* is it in a batchable area ? */
+
+        for (i = 0; i < dev->nb_zones; i++) {
+                zone = &dev->zone[i];
+
+                /* (addr,len) is fully included in
+                 * (zone->addr, zone->size)
+                 */
+
+                if (zone->addr <= addr &&
+                    addr + len <= zone->addr + zone->size)
+                        return 1;
+        }
+        return 0;
+}
+
+static void coalesced_mmio_write(struct kvm_io_device *this,
+                                 gpa_t addr, int len, const void *val)
+{
+        struct kvm_coalesced_mmio_dev *dev =
+                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
+
+        /* kvm->lock must be taken by caller before call to in_range()*/
+
+        /* copy data in first free entry of the ring */
+
+        ring->coalesced_mmio[ring->last].phys_addr = addr;
+        ring->coalesced_mmio[ring->last].len = len;
+        memcpy(ring->coalesced_mmio[ring->last].data, val, len);
+        smp_wmb();
+        ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
+}
+
+static void coalesced_mmio_destructor(struct kvm_io_device *this)
+{
+        kfree(this);
+}
+
+int kvm_coalesced_mmio_init(struct kvm *kvm)
+{
+        struct kvm_coalesced_mmio_dev *dev;
+
+        dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
+        if (!dev)
+                return -ENOMEM;
+        dev->dev.write  = coalesced_mmio_write;
+        dev->dev.in_range  = coalesced_mmio_in_range;
+        dev->dev.destructor  = coalesced_mmio_destructor;
+        dev->dev.private  = dev;
+        dev->kvm = kvm;
+        kvm->coalesced_mmio_dev = dev;
+        kvm_io_bus_register_dev(&kvm->mmio_bus, &dev->dev);
+
+        return 0;
+}
+
+int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
+                                         struct kvm_coalesced_mmio_zone *zone)
+{
+        struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
+
+        if (dev == NULL)
+                return -EINVAL;
+
+        mutex_lock(&kvm->lock);
+        if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
+                mutex_unlock(&kvm->lock);
+                return -ENOBUFS;
+        }
+
+        dev->zone[dev->nb_zones] = *zone;
+        dev->nb_zones++;
+
+        mutex_unlock(&kvm->lock);
+        return 0;
+}
+
+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 -EINVAL;
+
+        mutex_lock(&kvm->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];
+                }
+                i--;
+        }
+
+        mutex_unlock(&kvm->lock);
+
+        return 0;
+}