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1/*
2 * KVM coalesced MMIO
3 *
4 * Copyright (c) 2008 Bull S.A.S.
5 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
6 *
7 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
8 *
9 */
10
11#include "iodev.h"
12
13#include <linux/kvm_host.h>
14#include <linux/slab.h>
15#include <linux/kvm.h>
16
17#include "coalesced_mmio.h"
18
19static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
20{
21 return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
22}
23
24static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
25 gpa_t addr, int len)
26{
27 struct kvm_coalesced_mmio_zone *zone;
28 struct kvm_coalesced_mmio_ring *ring;
29 unsigned avail;
30 int i;
31
32 /* Are we able to batch it ? */
33
34 /* last is the first free entry
35 * check if we don't meet the first used entry
36 * there is always one unused entry in the buffer
37 */
38 ring = dev->kvm->coalesced_mmio_ring;
39 avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
40 if (avail < KVM_MAX_VCPUS) {
41 /* full */
42 return 0;
43 }
44
45 /* is it in a batchable area ? */
46
47 for (i = 0; i < dev->nb_zones; i++) {
48 zone = &dev->zone[i];
49
50 /* (addr,len) is fully included in
51 * (zone->addr, zone->size)
52 */
53
54 if (zone->addr <= addr &&
55 addr + len <= zone->addr + zone->size)
56 return 1;
57 }
58 return 0;
59}
60
61static int coalesced_mmio_write(struct kvm_io_device *this,
62 gpa_t addr, int len, const void *val)
63{
64 struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
65 struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
66 if (!coalesced_mmio_in_range(dev, addr, len))
67 return -EOPNOTSUPP;
68
69 spin_lock(&dev->lock);
70
71 /* copy data in first free entry of the ring */
72
73 ring->coalesced_mmio[ring->last].phys_addr = addr;
74 ring->coalesced_mmio[ring->last].len = len;
75 memcpy(ring->coalesced_mmio[ring->last].data, val, len);
76 smp_wmb();
77 ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
78 spin_unlock(&dev->lock);
79 return 0;
80}
81
82static void coalesced_mmio_destructor(struct kvm_io_device *this)
83{
84 struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
85
86 kfree(dev);
87}
88
89static const struct kvm_io_device_ops coalesced_mmio_ops = {
90 .write = coalesced_mmio_write,
91 .destructor = coalesced_mmio_destructor,
92};
93
94int kvm_coalesced_mmio_init(struct kvm *kvm)
95{
96 struct kvm_coalesced_mmio_dev *dev;
97 struct page *page;
98 int ret;
99
100 ret = -ENOMEM;
101 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
102 if (!page)
103 goto out_err;
104 kvm->coalesced_mmio_ring = page_address(page);
105
106 ret = -ENOMEM;
107 dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
108 if (!dev)
109 goto out_free_page;
110 spin_lock_init(&dev->lock);
111 kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
112 dev->kvm = kvm;
113 kvm->coalesced_mmio_dev = dev;
114
115 mutex_lock(&kvm->slots_lock);
116 ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, &dev->dev);
117 mutex_unlock(&kvm->slots_lock);
118 if (ret < 0)
119 goto out_free_dev;
120
121 return ret;
122
123out_free_dev:
124 kvm->coalesced_mmio_dev = NULL;
125 kfree(dev);
126out_free_page:
127 kvm->coalesced_mmio_ring = NULL;
128 __free_page(page);
129out_err:
130 return ret;
131}
132
133void kvm_coalesced_mmio_free(struct kvm *kvm)
134{
135 if (kvm->coalesced_mmio_ring)
136 free_page((unsigned long)kvm->coalesced_mmio_ring);
137}
138
139int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
140 struct kvm_coalesced_mmio_zone *zone)
141{
142 struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
143
144 if (dev == NULL)
145 return -ENXIO;
146
147 mutex_lock(&kvm->slots_lock);
148 if (dev->nb_zones >= KVM_COALESCED_MMIO_ZONE_MAX) {
149 mutex_unlock(&kvm->slots_lock);
150 return -ENOBUFS;
151 }
152
153 dev->zone[dev->nb_zones] = *zone;
154 dev->nb_zones++;
155
156 mutex_unlock(&kvm->slots_lock);
157 return 0;
158}
159
160int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
161 struct kvm_coalesced_mmio_zone *zone)
162{
163 int i;
164 struct kvm_coalesced_mmio_dev *dev = kvm->coalesced_mmio_dev;
165 struct kvm_coalesced_mmio_zone *z;
166
167 if (dev == NULL)
168 return -ENXIO;
169
170 mutex_lock(&kvm->slots_lock);
171
172 i = dev->nb_zones;
173 while (i) {
174 z = &dev->zone[i - 1];
175
176 /* unregister all zones
177 * included in (zone->addr, zone->size)
178 */
179
180 if (zone->addr <= z->addr &&
181 z->addr + z->size <= zone->addr + zone->size) {
182 dev->nb_zones--;
183 *z = dev->zone[dev->nb_zones];
184 }
185 i--;
186 }
187
188 mutex_unlock(&kvm->slots_lock);
189
190 return 0;
191}
1/*
2 * KVM coalesced MMIO
3 *
4 * Copyright (c) 2008 Bull S.A.S.
5 * Copyright 2009 Red Hat, Inc. and/or its affiliates.
6 *
7 * Author: Laurent Vivier <Laurent.Vivier@bull.net>
8 *
9 */
10
11#include <kvm/iodev.h>
12
13#include <linux/kvm_host.h>
14#include <linux/slab.h>
15#include <linux/kvm.h>
16
17#include "coalesced_mmio.h"
18
19static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
20{
21 return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
22}
23
24static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
25 gpa_t addr, int len)
26{
27 /* is it in a batchable area ?
28 * (addr,len) is fully included in
29 * (zone->addr, zone->size)
30 */
31 if (len < 0)
32 return 0;
33 if (addr + len < addr)
34 return 0;
35 if (addr < dev->zone.addr)
36 return 0;
37 if (addr + len > dev->zone.addr + dev->zone.size)
38 return 0;
39 return 1;
40}
41
42static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev)
43{
44 struct kvm_coalesced_mmio_ring *ring;
45 unsigned avail;
46
47 /* Are we able to batch it ? */
48
49 /* last is the first free entry
50 * check if we don't meet the first used entry
51 * there is always one unused entry in the buffer
52 */
53 ring = dev->kvm->coalesced_mmio_ring;
54 avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX;
55 if (avail == 0) {
56 /* full */
57 return 0;
58 }
59
60 return 1;
61}
62
63static int coalesced_mmio_write(struct kvm_vcpu *vcpu,
64 struct kvm_io_device *this, gpa_t addr,
65 int len, const void *val)
66{
67 struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
68 struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
69
70 if (!coalesced_mmio_in_range(dev, addr, len))
71 return -EOPNOTSUPP;
72
73 spin_lock(&dev->kvm->ring_lock);
74
75 if (!coalesced_mmio_has_room(dev)) {
76 spin_unlock(&dev->kvm->ring_lock);
77 return -EOPNOTSUPP;
78 }
79
80 /* copy data in first free entry of the ring */
81
82 ring->coalesced_mmio[ring->last].phys_addr = addr;
83 ring->coalesced_mmio[ring->last].len = len;
84 memcpy(ring->coalesced_mmio[ring->last].data, val, len);
85 smp_wmb();
86 ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX;
87 spin_unlock(&dev->kvm->ring_lock);
88 return 0;
89}
90
91static void coalesced_mmio_destructor(struct kvm_io_device *this)
92{
93 struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
94
95 list_del(&dev->list);
96
97 kfree(dev);
98}
99
100static const struct kvm_io_device_ops coalesced_mmio_ops = {
101 .write = coalesced_mmio_write,
102 .destructor = coalesced_mmio_destructor,
103};
104
105int kvm_coalesced_mmio_init(struct kvm *kvm)
106{
107 struct page *page;
108 int ret;
109
110 ret = -ENOMEM;
111 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
112 if (!page)
113 goto out_err;
114
115 ret = 0;
116 kvm->coalesced_mmio_ring = page_address(page);
117
118 /*
119 * We're using this spinlock to sync access to the coalesced ring.
120 * The list doesn't need it's own lock since device registration and
121 * unregistration should only happen when kvm->slots_lock is held.
122 */
123 spin_lock_init(&kvm->ring_lock);
124 INIT_LIST_HEAD(&kvm->coalesced_zones);
125
126out_err:
127 return ret;
128}
129
130void kvm_coalesced_mmio_free(struct kvm *kvm)
131{
132 if (kvm->coalesced_mmio_ring)
133 free_page((unsigned long)kvm->coalesced_mmio_ring);
134}
135
136int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm,
137 struct kvm_coalesced_mmio_zone *zone)
138{
139 int ret;
140 struct kvm_coalesced_mmio_dev *dev;
141
142 dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
143 if (!dev)
144 return -ENOMEM;
145
146 kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
147 dev->kvm = kvm;
148 dev->zone = *zone;
149
150 mutex_lock(&kvm->slots_lock);
151 ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, zone->addr,
152 zone->size, &dev->dev);
153 if (ret < 0)
154 goto out_free_dev;
155 list_add_tail(&dev->list, &kvm->coalesced_zones);
156 mutex_unlock(&kvm->slots_lock);
157
158 return 0;
159
160out_free_dev:
161 mutex_unlock(&kvm->slots_lock);
162 kfree(dev);
163
164 return ret;
165}
166
167int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm,
168 struct kvm_coalesced_mmio_zone *zone)
169{
170 struct kvm_coalesced_mmio_dev *dev, *tmp;
171
172 mutex_lock(&kvm->slots_lock);
173
174 list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list)
175 if (coalesced_mmio_in_range(dev, zone->addr, zone->size)) {
176 kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &dev->dev);
177 kvm_iodevice_destructor(&dev->dev);
178 }
179
180 mutex_unlock(&kvm->slots_lock);
181
182 return 0;
183}