Commit | Line | Data |
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d7e28ffe RR |
1 | /* Userspace control of the guest, via /dev/lguest. */ |
2 | #include <linux/uaccess.h> | |
3 | #include <linux/miscdevice.h> | |
4 | #include <linux/fs.h> | |
5 | #include "lg.h" | |
6 | ||
7 | static void setup_regs(struct lguest_regs *regs, unsigned long start) | |
8 | { | |
9 | /* Write out stack in format lguest expects, so we can switch to it. */ | |
10 | regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL; | |
11 | regs->cs = __KERNEL_CS|GUEST_PL; | |
12 | regs->eflags = 0x202; /* Interrupts enabled. */ | |
13 | regs->eip = start; | |
14 | /* esi points to our boot information (physical address 0) */ | |
15 | } | |
16 | ||
17 | /* + addr */ | |
18 | static long user_get_dma(struct lguest *lg, const u32 __user *input) | |
19 | { | |
20 | unsigned long key, udma, irq; | |
21 | ||
22 | if (get_user(key, input) != 0) | |
23 | return -EFAULT; | |
24 | udma = get_dma_buffer(lg, key, &irq); | |
25 | if (!udma) | |
26 | return -ENOENT; | |
27 | ||
28 | /* We put irq number in udma->used_len. */ | |
29 | lgwrite_u32(lg, udma + offsetof(struct lguest_dma, used_len), irq); | |
30 | return udma; | |
31 | } | |
32 | ||
33 | /* To force the Guest to stop running and return to the Launcher, the | |
34 | * Waker sets writes LHREQ_BREAK and the value "1" to /dev/lguest. The | |
35 | * Launcher then writes LHREQ_BREAK and "0" to release the Waker. */ | |
36 | static int break_guest_out(struct lguest *lg, const u32 __user *input) | |
37 | { | |
38 | unsigned long on; | |
39 | ||
40 | /* Fetch whether they're turning break on or off.. */ | |
41 | if (get_user(on, input) != 0) | |
42 | return -EFAULT; | |
43 | ||
44 | if (on) { | |
45 | lg->break_out = 1; | |
46 | /* Pop it out (may be running on different CPU) */ | |
47 | wake_up_process(lg->tsk); | |
48 | /* Wait for them to reset it */ | |
49 | return wait_event_interruptible(lg->break_wq, !lg->break_out); | |
50 | } else { | |
51 | lg->break_out = 0; | |
52 | wake_up(&lg->break_wq); | |
53 | return 0; | |
54 | } | |
55 | } | |
56 | ||
57 | /* + irq */ | |
58 | static int user_send_irq(struct lguest *lg, const u32 __user *input) | |
59 | { | |
60 | u32 irq; | |
61 | ||
62 | if (get_user(irq, input) != 0) | |
63 | return -EFAULT; | |
64 | if (irq >= LGUEST_IRQS) | |
65 | return -EINVAL; | |
66 | set_bit(irq, lg->irqs_pending); | |
67 | return 0; | |
68 | } | |
69 | ||
70 | static ssize_t read(struct file *file, char __user *user, size_t size,loff_t*o) | |
71 | { | |
72 | struct lguest *lg = file->private_data; | |
73 | ||
74 | if (!lg) | |
75 | return -EINVAL; | |
76 | ||
77 | /* If you're not the task which owns the guest, go away. */ | |
78 | if (current != lg->tsk) | |
79 | return -EPERM; | |
80 | ||
81 | if (lg->dead) { | |
82 | size_t len; | |
83 | ||
84 | if (IS_ERR(lg->dead)) | |
85 | return PTR_ERR(lg->dead); | |
86 | ||
87 | len = min(size, strlen(lg->dead)+1); | |
88 | if (copy_to_user(user, lg->dead, len) != 0) | |
89 | return -EFAULT; | |
90 | return len; | |
91 | } | |
92 | ||
93 | if (lg->dma_is_pending) | |
94 | lg->dma_is_pending = 0; | |
95 | ||
96 | return run_guest(lg, (unsigned long __user *)user); | |
97 | } | |
98 | ||
99 | /* Take: pfnlimit, pgdir, start, pageoffset. */ | |
100 | static int initialize(struct file *file, const u32 __user *input) | |
101 | { | |
102 | struct lguest *lg; | |
103 | int err, i; | |
104 | u32 args[4]; | |
105 | ||
106 | /* We grab the Big Lguest lock, which protects the global array | |
107 | * "lguests" and multiple simultaneous initializations. */ | |
108 | mutex_lock(&lguest_lock); | |
109 | ||
110 | if (file->private_data) { | |
111 | err = -EBUSY; | |
112 | goto unlock; | |
113 | } | |
114 | ||
115 | if (copy_from_user(args, input, sizeof(args)) != 0) { | |
116 | err = -EFAULT; | |
117 | goto unlock; | |
118 | } | |
119 | ||
120 | i = find_free_guest(); | |
121 | if (i < 0) { | |
122 | err = -ENOSPC; | |
123 | goto unlock; | |
124 | } | |
125 | lg = &lguests[i]; | |
126 | lg->guestid = i; | |
127 | lg->pfn_limit = args[0]; | |
128 | lg->page_offset = args[3]; | |
129 | lg->regs_page = get_zeroed_page(GFP_KERNEL); | |
130 | if (!lg->regs_page) { | |
131 | err = -ENOMEM; | |
132 | goto release_guest; | |
133 | } | |
134 | lg->regs = (void *)lg->regs_page + PAGE_SIZE - sizeof(*lg->regs); | |
135 | ||
136 | err = init_guest_pagetable(lg, args[1]); | |
137 | if (err) | |
138 | goto free_regs; | |
139 | ||
140 | setup_regs(lg->regs, args[2]); | |
141 | setup_guest_gdt(lg); | |
142 | init_clockdev(lg); | |
143 | lg->tsk = current; | |
144 | lg->mm = get_task_mm(lg->tsk); | |
145 | init_waitqueue_head(&lg->break_wq); | |
146 | lg->last_pages = NULL; | |
147 | file->private_data = lg; | |
148 | ||
149 | mutex_unlock(&lguest_lock); | |
150 | ||
151 | return sizeof(args); | |
152 | ||
153 | free_regs: | |
154 | free_page(lg->regs_page); | |
155 | release_guest: | |
156 | memset(lg, 0, sizeof(*lg)); | |
157 | unlock: | |
158 | mutex_unlock(&lguest_lock); | |
159 | return err; | |
160 | } | |
161 | ||
162 | static ssize_t write(struct file *file, const char __user *input, | |
163 | size_t size, loff_t *off) | |
164 | { | |
165 | struct lguest *lg = file->private_data; | |
166 | u32 req; | |
167 | ||
168 | if (get_user(req, input) != 0) | |
169 | return -EFAULT; | |
170 | input += sizeof(req); | |
171 | ||
172 | if (req != LHREQ_INITIALIZE && !lg) | |
173 | return -EINVAL; | |
174 | if (lg && lg->dead) | |
175 | return -ENOENT; | |
176 | ||
177 | /* If you're not the task which owns the Guest, you can only break */ | |
178 | if (lg && current != lg->tsk && req != LHREQ_BREAK) | |
179 | return -EPERM; | |
180 | ||
181 | switch (req) { | |
182 | case LHREQ_INITIALIZE: | |
183 | return initialize(file, (const u32 __user *)input); | |
184 | case LHREQ_GETDMA: | |
185 | return user_get_dma(lg, (const u32 __user *)input); | |
186 | case LHREQ_IRQ: | |
187 | return user_send_irq(lg, (const u32 __user *)input); | |
188 | case LHREQ_BREAK: | |
189 | return break_guest_out(lg, (const u32 __user *)input); | |
190 | default: | |
191 | return -EINVAL; | |
192 | } | |
193 | } | |
194 | ||
195 | static int close(struct inode *inode, struct file *file) | |
196 | { | |
197 | struct lguest *lg = file->private_data; | |
198 | ||
199 | if (!lg) | |
200 | return 0; | |
201 | ||
202 | mutex_lock(&lguest_lock); | |
203 | /* Cancels the hrtimer set via LHCALL_SET_CLOCKEVENT. */ | |
204 | hrtimer_cancel(&lg->hrt); | |
205 | release_all_dma(lg); | |
206 | free_guest_pagetable(lg); | |
207 | mmput(lg->mm); | |
208 | if (!IS_ERR(lg->dead)) | |
209 | kfree(lg->dead); | |
210 | free_page(lg->regs_page); | |
211 | memset(lg, 0, sizeof(*lg)); | |
212 | mutex_unlock(&lguest_lock); | |
213 | return 0; | |
214 | } | |
215 | ||
216 | static struct file_operations lguest_fops = { | |
217 | .owner = THIS_MODULE, | |
218 | .release = close, | |
219 | .write = write, | |
220 | .read = read, | |
221 | }; | |
222 | static struct miscdevice lguest_dev = { | |
223 | .minor = MISC_DYNAMIC_MINOR, | |
224 | .name = "lguest", | |
225 | .fops = &lguest_fops, | |
226 | }; | |
227 | ||
228 | int __init lguest_device_init(void) | |
229 | { | |
230 | return misc_register(&lguest_dev); | |
231 | } | |
232 | ||
233 | void __exit lguest_device_remove(void) | |
234 | { | |
235 | misc_deregister(&lguest_dev); | |
236 | } |