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[linux-2.6/mini2440.git] / virt / kvm / coalesced_mmio.c
blob5ae620d32fac7cb29692b6e1348da6580942fd5d
1 /*
2 * KVM coalesced MMIO
4 * Copyright (c) 2008 Bull S.A.S.
6 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
8 */
10 #include "iodev.h"
12 #include <linux/kvm_host.h>
13 #include <linux/kvm.h>
15 #include "coalesced_mmio.h"
17 static int coalesced_mmio_in_range(struct kvm_io_device *this,
18 gpa_t addr, int len, int is_write)
20 struct kvm_coalesced_mmio_dev *dev =
21 (struct kvm_coalesced_mmio_dev*)this->private;
22 struct kvm_coalesced_mmio_zone *zone;
23 int next;
24 int i;
26 if (!is_write)
27 return 0;
29 /* kvm->lock is taken by the caller and must be not released before
30 * dev.read/write
33 /* Are we able to batch it ? */
35 /* last is the first free entry
36 * check if we don't meet the first used entry
37 * there is always one unused entry in the buffer
40 next = (dev->kvm->coalesced_mmio_ring->last + 1) %
41 KVM_COALESCED_MMIO_MAX;
42 if (next == dev->kvm->coalesced_mmio_ring->first) {
43 /* full */
44 return 0;
47 /* is it in a batchable area ? */
49 for (i = 0; i < dev->nb_zones; i++) {
50 zone = &dev->zone[i];
52 /* (addr,len) is fully included in
53 * (zone->addr, zone->size)
56 if (zone->addr <= addr &&
57 addr + len <= zone->addr + zone->size)
58 return 1;
60 return 0;
63 static void coalesced_mmio_write(struct kvm_io_device *this,
64 gpa_t addr, int len, const void *val)
66 struct kvm_coalesced_mmio_dev *dev =
67 (struct kvm_coalesced_mmio_dev*)this->private;
68 struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
70 /* kvm->lock must be taken by caller before call to in_range()*/
72 /* copy data in first free entry of the ring */
74 ring->coalesced_mmio[ring->last].phys_addr = addr;
75 ring->coalesced_mmio[ring->last].len = len;
76 memcpy(ring->coalesced_mmio[ring->last].data, val, len);
77 smp_wmb();
78 ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
81 static void coalesced_mmio_destructor(struct kvm_io_device *this)
83 kfree(this);
86 int kvm_coalesced_mmio_init(struct kvm *kvm)
88 struct kvm_coalesced_mmio_dev *dev;
90 dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
91 if (!dev)
92 return -ENOMEM;
93 dev->dev.write = coalesced_mmio_write;
94 dev->dev.in_range = coalesced_mmio_in_range;
95 dev->dev.destructor = coalesced_mmio_destructor;
96 dev->dev.private = dev;
97 dev->kvm = kvm;
98 kvm->coalesced_mmio_dev = dev;
99 kvm_io_bus_register_dev(&kvm->mmio_bus, &dev->dev);
101 return 0;
104 int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
105 struct kvm_coalesced_mmio_zone *zone)
107 struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
109 if (dev == NULL)
110 return -EINVAL;
112 mutex_lock(&kvm->lock);
113 if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
114 mutex_unlock(&kvm->lock);
115 return -ENOBUFS;
118 dev->zone[dev->nb_zones] = *zone;
119 dev->nb_zones++;
121 mutex_unlock(&kvm->lock);
122 return 0;
125 int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
126 struct kvm_coalesced_mmio_zone *zone)
128 int i;
129 struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
130 struct kvm_coalesced_mmio_zone *z;
132 if (dev == NULL)
133 return -EINVAL;
135 mutex_lock(&kvm->lock);
137 i = dev->nb_zones;
138 while(i) {
139 z = &dev->zone[i - 1];
141 /* unregister all zones
142 * included in (zone->addr, zone->size)
145 if (zone->addr <= z->addr &&
146 z->addr + z->size <= zone->addr + zone->size) {
147 dev->nb_zones--;
148 *z = dev->zone[dev->nb_zones];
150 i--;
153 mutex_unlock(&kvm->lock);
155 return 0;