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Commit | Line | Data |
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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 <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 | ||
19 | static 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 | ||
24 | static 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 | ||
42 | static 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 | ||
63 | static 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 | ||
91 | static 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 | ||
100 | static const struct kvm_io_device_ops coalesced_mmio_ops = { | |
101 | .write = coalesced_mmio_write, | |
102 | .destructor = coalesced_mmio_destructor, | |
103 | }; | |
104 | ||
105 | int 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 | ||
126 | out_err: | |
127 | return ret; | |
128 | } | |
129 | ||
130 | void 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 | ||
136 | int 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 | ||
160 | out_free_dev: | |
161 | mutex_unlock(&kvm->slots_lock); | |
162 | kfree(dev); | |
163 | ||
164 | return ret; | |
165 | } | |
166 | ||
167 | int 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 | } |