summaryrefslogtreecommitdiffstats
path: root/virt/kvm/coalesced_mmio.c
diff options
context:
space:
mode:
Diffstat (limited to 'virt/kvm/coalesced_mmio.c')
-rw-r--r--virt/kvm/coalesced_mmio.c156
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 0000000..5ae620d
--- /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;
+}
OpenPOWER on IntegriCloud