1 | /* |
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2 | * PCI Backend - Provides a Virtual PCI bus (with real devices) |
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3 | * to the frontend |
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4 | * |
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5 | * Author: Ryan Wilson <hap9@epoch.ncsc.mil> |
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6 | */ |
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7 | |
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8 | #include <linux/list.h> |
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9 | #include <linux/slab.h> |
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10 | #include <linux/pci.h> |
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11 | #include <linux/spinlock.h> |
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12 | #include "pciback.h" |
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13 | |
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14 | #define PCI_SLOT_MAX 32 |
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15 | |
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16 | struct vpci_dev_data { |
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17 | /* Access to dev_list must be protected by lock */ |
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18 | struct list_head dev_list[PCI_SLOT_MAX]; |
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19 | spinlock_t lock; |
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20 | }; |
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21 | |
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22 | static inline struct list_head *list_first(struct list_head *head) |
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23 | { |
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24 | return head->next; |
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25 | } |
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26 | |
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27 | struct pci_dev *pciback_get_pci_dev(struct pciback_device *pdev, |
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28 | unsigned int domain, unsigned int bus, |
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29 | unsigned int devfn) |
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30 | { |
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31 | struct pci_dev_entry *entry; |
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32 | struct pci_dev *dev = NULL; |
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33 | struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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34 | unsigned long flags; |
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35 | |
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36 | if (domain != 0 || bus != 0) |
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37 | return NULL; |
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38 | |
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39 | if (PCI_SLOT(devfn) < PCI_SLOT_MAX) { |
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40 | spin_lock_irqsave(&vpci_dev->lock, flags); |
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41 | |
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42 | list_for_each_entry(entry, |
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43 | &vpci_dev->dev_list[PCI_SLOT(devfn)], |
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44 | list) { |
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45 | if (PCI_FUNC(entry->dev->devfn) == PCI_FUNC(devfn)) { |
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46 | dev = entry->dev; |
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47 | break; |
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48 | } |
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49 | } |
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50 | |
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51 | spin_unlock_irqrestore(&vpci_dev->lock, flags); |
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52 | } |
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53 | return dev; |
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54 | } |
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55 | |
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56 | static inline int match_slot(struct pci_dev *l, struct pci_dev *r) |
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57 | { |
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58 | if (pci_domain_nr(l->bus) == pci_domain_nr(r->bus) |
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59 | && l->bus == r->bus && PCI_SLOT(l->devfn) == PCI_SLOT(r->devfn)) |
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60 | return 1; |
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61 | |
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62 | return 0; |
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63 | } |
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64 | |
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65 | int pciback_add_pci_dev(struct pciback_device *pdev, struct pci_dev *dev) |
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66 | { |
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67 | int err = 0, slot; |
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68 | struct pci_dev_entry *t, *dev_entry; |
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69 | struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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70 | unsigned long flags; |
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71 | |
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72 | if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) { |
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73 | err = -EFAULT; |
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74 | xenbus_dev_fatal(pdev->xdev, err, |
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75 | "Can't export bridges on the virtual PCI bus"); |
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76 | goto out; |
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77 | } |
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78 | |
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79 | dev_entry = kmalloc(sizeof(*dev_entry), GFP_KERNEL); |
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80 | if (!dev_entry) { |
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81 | err = -ENOMEM; |
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82 | xenbus_dev_fatal(pdev->xdev, err, |
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83 | "Error adding entry to virtual PCI bus"); |
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84 | goto out; |
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85 | } |
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86 | |
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87 | dev_entry->dev = dev; |
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88 | |
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89 | spin_lock_irqsave(&vpci_dev->lock, flags); |
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90 | |
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91 | /* Keep multi-function devices together on the virtual PCI bus */ |
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92 | for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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93 | if (!list_empty(&vpci_dev->dev_list[slot])) { |
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94 | t = list_entry(list_first(&vpci_dev->dev_list[slot]), |
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95 | struct pci_dev_entry, list); |
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96 | |
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97 | if (match_slot(dev, t->dev)) { |
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98 | pr_info("pciback: vpci: %s: " |
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99 | "assign to virtual slot %d func %d\n", |
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100 | pci_name(dev), slot, |
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101 | PCI_FUNC(dev->devfn)); |
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102 | list_add_tail(&dev_entry->list, |
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103 | &vpci_dev->dev_list[slot]); |
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104 | goto unlock; |
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105 | } |
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106 | } |
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107 | } |
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108 | |
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109 | /* Assign to a new slot on the virtual PCI bus */ |
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110 | for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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111 | if (list_empty(&vpci_dev->dev_list[slot])) { |
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112 | printk(KERN_INFO |
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113 | "pciback: vpci: %s: assign to virtual slot %d\n", |
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114 | pci_name(dev), slot); |
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115 | list_add_tail(&dev_entry->list, |
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116 | &vpci_dev->dev_list[slot]); |
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117 | goto unlock; |
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118 | } |
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119 | } |
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120 | |
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121 | err = -ENOMEM; |
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122 | xenbus_dev_fatal(pdev->xdev, err, |
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123 | "No more space on root virtual PCI bus"); |
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124 | |
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125 | unlock: |
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126 | spin_unlock_irqrestore(&vpci_dev->lock, flags); |
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127 | out: |
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128 | return err; |
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129 | } |
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130 | |
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131 | void pciback_release_pci_dev(struct pciback_device *pdev, struct pci_dev *dev) |
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132 | { |
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133 | int slot; |
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134 | struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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135 | struct pci_dev *found_dev = NULL; |
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136 | unsigned long flags; |
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137 | |
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138 | spin_lock_irqsave(&vpci_dev->lock, flags); |
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139 | |
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140 | for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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141 | struct pci_dev_entry *e, *tmp; |
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142 | list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot], |
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143 | list) { |
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144 | if (e->dev == dev) { |
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145 | list_del(&e->list); |
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146 | found_dev = e->dev; |
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147 | kfree(e); |
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148 | goto out; |
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149 | } |
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150 | } |
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151 | } |
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152 | |
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153 | out: |
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154 | spin_unlock_irqrestore(&vpci_dev->lock, flags); |
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155 | |
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156 | if (found_dev) |
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157 | pcistub_put_pci_dev(found_dev); |
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158 | } |
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159 | |
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160 | int pciback_init_devices(struct pciback_device *pdev) |
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161 | { |
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162 | int slot; |
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163 | struct vpci_dev_data *vpci_dev; |
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164 | |
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165 | vpci_dev = kmalloc(sizeof(*vpci_dev), GFP_KERNEL); |
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166 | if (!vpci_dev) |
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167 | return -ENOMEM; |
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168 | |
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169 | spin_lock_init(&vpci_dev->lock); |
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170 | |
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171 | for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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172 | INIT_LIST_HEAD(&vpci_dev->dev_list[slot]); |
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173 | } |
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174 | |
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175 | pdev->pci_dev_data = vpci_dev; |
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176 | |
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177 | return 0; |
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178 | } |
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179 | |
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180 | int pciback_publish_pci_roots(struct pciback_device *pdev, |
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181 | publish_pci_root_cb publish_cb) |
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182 | { |
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183 | /* The Virtual PCI bus has only one root */ |
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184 | return publish_cb(pdev, 0, 0); |
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185 | } |
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186 | |
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187 | void pciback_release_devices(struct pciback_device *pdev) |
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188 | { |
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189 | int slot; |
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190 | struct vpci_dev_data *vpci_dev = pdev->pci_dev_data; |
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191 | |
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192 | for (slot = 0; slot < PCI_SLOT_MAX; slot++) { |
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193 | struct pci_dev_entry *e, *tmp; |
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194 | list_for_each_entry_safe(e, tmp, &vpci_dev->dev_list[slot], |
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195 | list) { |
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196 | list_del(&e->list); |
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197 | pcistub_put_pci_dev(e->dev); |
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198 | kfree(e); |
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199 | } |
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200 | } |
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201 | |
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202 | kfree(vpci_dev); |
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203 | pdev->pci_dev_data = NULL; |
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204 | } |
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