Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / virt / kvm / coalesced_mmio.c

diff --git a/kernel/virt/kvm/coalesced_mmio.c b/kernel/virt/kvm/coalesced_mmio.c
new file mode 100644 (file)
index 0000000..571c1ce
--- /dev/null
+++ b/kernel/virt/kvm/coalesced_mmio.c
@@ -0,0 +1,183 @@
+/*
+ * KVM coalesced MMIO
+ *
+ * Copyright (c) 2008 Bull S.A.S.
+ * Copyright 2009 Red Hat, Inc. and/or its affiliates.
+ *
+ *  Author: Laurent Vivier <Laurent.Vivier@bull.net>
+ *
+ */
+
+#include <kvm/iodev.h>
+
+#include <linux/kvm_host.h>
+#include <linux/slab.h>
+#include <linux/kvm.h>
+
+#include "coalesced_mmio.h"
+
+static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
+{
+       return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
+}
+
+static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
+                                  gpa_t addr, int len)
+{
+       /* is it in a batchable area ?
+        * (addr,len) is fully included in
+        * (zone->addr, zone->size)
+        */
+       if (len < 0)
+               return 0;
+       if (addr + len < addr)
+               return 0;
+       if (addr < dev->zone.addr)
+               return 0;
+       if (addr + len > dev->zone.addr + dev->zone.size)
+               return 0;
+       return 1;
+}
+
+static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev)
+{
+       struct kvm_coalesced_mmio_ring *ring;
+       unsigned avail;
+
+       /* 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
+        */
+       ring = dev->kvm->coalesced_mmio_ring;
+       avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
+       if (avail == 0) {
+               /* full */
+               return 0;
+       }
+
+       return 1;
+}
+
+static int coalesced_mmio_write(struct kvm_vcpu *vcpu,
+                               struct kvm_io_device *this, gpa_t addr,
+                               int len, const void *val)
+{
+       struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
+       struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
+
+       if (!coalesced_mmio_in_range(dev, addr, len))
+               return -EOPNOTSUPP;
+
+       spin_lock(&dev->kvm->ring_lock);
+
+       if (!coalesced_mmio_has_room(dev)) {
+               spin_unlock(&dev->kvm->ring_lock);
+               return -EOPNOTSUPP;
+       }
+
+       /* 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;
+       spin_unlock(&dev->kvm->ring_lock);
+       return 0;
+}
+
+static void coalesced_mmio_destructor(struct kvm_io_device *this)
+{
+       struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
+
+       list_del(&dev->list);
+
+       kfree(dev);
+}
+
+static const struct kvm_io_device_ops coalesced_mmio_ops = {
+       .write      = coalesced_mmio_write,
+       .destructor = coalesced_mmio_destructor,
+};
+
+int kvm_coalesced_mmio_init(struct kvm *kvm)
+{
+       struct page *page;
+       int ret;
+
+       ret = -ENOMEM;
+       page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+       if (!page)
+               goto out_err;
+
+       ret = 0;
+       kvm->coalesced_mmio_ring = page_address(page);
+
+       /*
+        * We're using this spinlock to sync access to the coalesced ring.
+        * The list doesn't need it's own lock since device registration and
+        * unregistration should only happen when kvm->slots_lock is held.
+        */
+       spin_lock_init(&kvm->ring_lock);
+       INIT_LIST_HEAD(&kvm->coalesced_zones);
+
+out_err:
+       return ret;
+}
+
+void kvm_coalesced_mmio_free(struct kvm *kvm)
+{
+       if (kvm->coalesced_mmio_ring)
+               free_page((unsigned long)kvm->coalesced_mmio_ring);
+}
+
+int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
+                                        struct kvm_coalesced_mmio_zone *zone)
+{
+       int ret;
+       struct kvm_coalesced_mmio_dev *dev;
+
+       dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
+       if (!dev)
+               return -ENOMEM;
+
+       kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
+       dev->kvm = kvm;
+       dev->zone = *zone;
+
+       mutex_lock(&kvm->slots_lock);
+       ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, zone->addr,
+                                     zone->size, &dev->dev);
+       if (ret < 0)
+               goto out_free_dev;
+       list_add_tail(&dev->list, &kvm->coalesced_zones);
+       mutex_unlock(&kvm->slots_lock);
+
+       return 0;
+
+out_free_dev:
+       mutex_unlock(&kvm->slots_lock);
+       kfree(dev);
+
+       return ret;
+}
+
+int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
+                                          struct kvm_coalesced_mmio_zone *zone)
+{
+       struct kvm_coalesced_mmio_dev *dev, *tmp;
+
+       mutex_lock(&kvm->slots_lock);
+
+       list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list)
+               if (coalesced_mmio_in_range(dev, zone->addr, zone->size)) {
+                       kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &dev->dev);
+                       kvm_iodevice_destructor(&dev->dev);
+               }
+
+       mutex_unlock(&kvm->slots_lock);
+
+       return 0;
+}