Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5f94c174 LV |
2 | /* |
3 | * KVM coalesced MMIO | |
4 | * | |
5 | * Copyright (c) 2008 Bull S.A.S. | |
221d059d | 6 | * Copyright 2009 Red Hat, Inc. and/or its affiliates. |
5f94c174 LV |
7 | * |
8 | * Author: Laurent Vivier <Laurent.Vivier@bull.net> | |
9 | * | |
10 | */ | |
11 | ||
af669ac6 | 12 | #include <kvm/iodev.h> |
5f94c174 LV |
13 | |
14 | #include <linux/kvm_host.h> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
5f94c174 LV |
16 | #include <linux/kvm.h> |
17 | ||
18 | #include "coalesced_mmio.h" | |
19 | ||
d76685c4 GH |
20 | static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev) |
21 | { | |
22 | return container_of(dev, struct kvm_coalesced_mmio_dev, dev); | |
23 | } | |
24 | ||
bda9020e MT |
25 | static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev, |
26 | gpa_t addr, int len) | |
5f94c174 | 27 | { |
2b3c246a SL |
28 | /* is it in a batchable area ? |
29 | * (addr,len) is fully included in | |
30 | * (zone->addr, zone->size) | |
31 | */ | |
1a214246 DC |
32 | if (len < 0) |
33 | return 0; | |
34 | if (addr + len < addr) | |
35 | return 0; | |
36 | if (addr < dev->zone.addr) | |
37 | return 0; | |
38 | if (addr + len > dev->zone.addr + dev->zone.size) | |
39 | return 0; | |
40 | return 1; | |
5f94c174 LV |
41 | } |
42 | ||
c298125f SL |
43 | static int coalesced_mmio_has_room(struct kvm_coalesced_mmio_dev *dev) |
44 | { | |
45 | struct kvm_coalesced_mmio_ring *ring; | |
46 | unsigned avail; | |
47 | ||
48 | /* Are we able to batch it ? */ | |
49 | ||
50 | /* last is the first free entry | |
51 | * check if we don't meet the first used entry | |
52 | * there is always one unused entry in the buffer | |
53 | */ | |
54 | ring = dev->kvm->coalesced_mmio_ring; | |
55 | avail = (ring->first - ring->last - 1) % KVM_COALESCED_MMIO_MAX; | |
56 | if (avail == 0) { | |
57 | /* full */ | |
58 | return 0; | |
59 | } | |
60 | ||
61 | return 1; | |
62 | } | |
63 | ||
e32edf4f NN |
64 | static int coalesced_mmio_write(struct kvm_vcpu *vcpu, |
65 | struct kvm_io_device *this, gpa_t addr, | |
66 | int len, const void *val) | |
5f94c174 | 67 | { |
d76685c4 | 68 | struct kvm_coalesced_mmio_dev *dev = to_mmio(this); |
5f94c174 | 69 | struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring; |
c298125f | 70 | |
bda9020e MT |
71 | if (!coalesced_mmio_in_range(dev, addr, len)) |
72 | return -EOPNOTSUPP; | |
5f94c174 | 73 | |
2b3c246a | 74 | spin_lock(&dev->kvm->ring_lock); |
5f94c174 | 75 | |
c298125f | 76 | if (!coalesced_mmio_has_room(dev)) { |
2b3c246a | 77 | spin_unlock(&dev->kvm->ring_lock); |
c298125f SL |
78 | return -EOPNOTSUPP; |
79 | } | |
80 | ||
5f94c174 LV |
81 | /* copy data in first free entry of the ring */ |
82 | ||
83 | ring->coalesced_mmio[ring->last].phys_addr = addr; | |
84 | ring->coalesced_mmio[ring->last].len = len; | |
85 | memcpy(ring->coalesced_mmio[ring->last].data, val, len); | |
86 | smp_wmb(); | |
87 | ring->last = (ring->last + 1) % KVM_COALESCED_MMIO_MAX; | |
2b3c246a | 88 | spin_unlock(&dev->kvm->ring_lock); |
bda9020e | 89 | return 0; |
5f94c174 LV |
90 | } |
91 | ||
92 | static void coalesced_mmio_destructor(struct kvm_io_device *this) | |
93 | { | |
d76685c4 | 94 | struct kvm_coalesced_mmio_dev *dev = to_mmio(this); |
787a660a | 95 | |
2b3c246a SL |
96 | list_del(&dev->list); |
97 | ||
787a660a | 98 | kfree(dev); |
5f94c174 LV |
99 | } |
100 | ||
d76685c4 GH |
101 | static const struct kvm_io_device_ops coalesced_mmio_ops = { |
102 | .write = coalesced_mmio_write, | |
d76685c4 GH |
103 | .destructor = coalesced_mmio_destructor, |
104 | }; | |
105 | ||
5f94c174 LV |
106 | int kvm_coalesced_mmio_init(struct kvm *kvm) |
107 | { | |
980da6ce | 108 | struct page *page; |
090b7aff | 109 | int ret; |
5f94c174 | 110 | |
980da6ce AK |
111 | ret = -ENOMEM; |
112 | page = alloc_page(GFP_KERNEL | __GFP_ZERO); | |
113 | if (!page) | |
114 | goto out_err; | |
980da6ce | 115 | |
2b3c246a SL |
116 | ret = 0; |
117 | kvm->coalesced_mmio_ring = page_address(page); | |
980da6ce | 118 | |
2b3c246a SL |
119 | /* |
120 | * We're using this spinlock to sync access to the coalesced ring. | |
121 | * The list doesn't need it's own lock since device registration and | |
122 | * unregistration should only happen when kvm->slots_lock is held. | |
123 | */ | |
124 | spin_lock_init(&kvm->ring_lock); | |
125 | INIT_LIST_HEAD(&kvm->coalesced_zones); | |
090b7aff | 126 | |
980da6ce | 127 | out_err: |
090b7aff | 128 | return ret; |
5f94c174 LV |
129 | } |
130 | ||
980da6ce AK |
131 | void kvm_coalesced_mmio_free(struct kvm *kvm) |
132 | { | |
133 | if (kvm->coalesced_mmio_ring) | |
134 | free_page((unsigned long)kvm->coalesced_mmio_ring); | |
135 | } | |
136 | ||
5f94c174 | 137 | int kvm_vm_ioctl_register_coalesced_mmio(struct kvm *kvm, |
43db6697 | 138 | struct kvm_coalesced_mmio_zone *zone) |
5f94c174 | 139 | { |
2b3c246a SL |
140 | int ret; |
141 | struct kvm_coalesced_mmio_dev *dev; | |
5f94c174 | 142 | |
2b3c246a SL |
143 | dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL); |
144 | if (!dev) | |
145 | return -ENOMEM; | |
146 | ||
147 | kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops); | |
148 | dev->kvm = kvm; | |
149 | dev->zone = *zone; | |
5f94c174 | 150 | |
79fac95e | 151 | mutex_lock(&kvm->slots_lock); |
743eeb0b SL |
152 | ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, zone->addr, |
153 | zone->size, &dev->dev); | |
2b3c246a SL |
154 | if (ret < 0) |
155 | goto out_free_dev; | |
156 | list_add_tail(&dev->list, &kvm->coalesced_zones); | |
157 | mutex_unlock(&kvm->slots_lock); | |
5f94c174 | 158 | |
aac5c422 | 159 | return 0; |
5f94c174 | 160 | |
2b3c246a | 161 | out_free_dev: |
79fac95e | 162 | mutex_unlock(&kvm->slots_lock); |
2b3c246a SL |
163 | kfree(dev); |
164 | ||
aac5c422 | 165 | return ret; |
5f94c174 LV |
166 | } |
167 | ||
168 | int kvm_vm_ioctl_unregister_coalesced_mmio(struct kvm *kvm, | |
169 | struct kvm_coalesced_mmio_zone *zone) | |
170 | { | |
2b3c246a | 171 | struct kvm_coalesced_mmio_dev *dev, *tmp; |
5f94c174 | 172 | |
79fac95e | 173 | mutex_lock(&kvm->slots_lock); |
5f94c174 | 174 | |
2b3c246a SL |
175 | list_for_each_entry_safe(dev, tmp, &kvm->coalesced_zones, list) |
176 | if (coalesced_mmio_in_range(dev, zone->addr, zone->size)) { | |
177 | kvm_io_bus_unregister_dev(kvm, KVM_MMIO_BUS, &dev->dev); | |
178 | kvm_iodevice_destructor(&dev->dev); | |
5f94c174 | 179 | } |
5f94c174 | 180 | |
79fac95e | 181 | mutex_unlock(&kvm->slots_lock); |
5f94c174 LV |
182 | |
183 | return 0; | |
184 | } |