Commit | Line | Data |
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d68d82af AN |
1 | #include <linux/notifier.h> |
2 | ||
3 | #include <xen/xenbus.h> | |
4 | ||
bb898558 | 5 | #include <asm/xen/hypervisor.h> |
d68d82af AN |
6 | #include <asm/cpu.h> |
7 | ||
8 | static void enable_hotplug_cpu(int cpu) | |
9 | { | |
10 | if (!cpu_present(cpu)) | |
11 | arch_register_cpu(cpu); | |
12 | ||
d680eb8b | 13 | set_cpu_present(cpu, true); |
d68d82af AN |
14 | } |
15 | ||
16 | static void disable_hotplug_cpu(int cpu) | |
17 | { | |
18 | if (cpu_present(cpu)) | |
19 | arch_unregister_cpu(cpu); | |
20 | ||
d680eb8b | 21 | set_cpu_present(cpu, false); |
d68d82af AN |
22 | } |
23 | ||
d745562c | 24 | static int vcpu_online(unsigned int cpu) |
d68d82af AN |
25 | { |
26 | int err; | |
27 | char dir[32], state[32]; | |
28 | ||
d68d82af AN |
29 | sprintf(dir, "cpu/%u", cpu); |
30 | err = xenbus_scanf(XBT_NIL, dir, "availability", "%s", state); | |
31 | if (err != 1) { | |
32 | printk(KERN_ERR "XENBUS: Unable to read cpu state\n"); | |
d745562c | 33 | return err; |
d68d82af AN |
34 | } |
35 | ||
d745562c IC |
36 | if (strcmp(state, "online") == 0) |
37 | return 1; | |
38 | else if (strcmp(state, "offline") == 0) | |
39 | return 0; | |
40 | ||
41 | printk(KERN_ERR "XENBUS: unknown state(%s) on CPU%d\n", state, cpu); | |
42 | return -EINVAL; | |
43 | } | |
44 | static void vcpu_hotplug(unsigned int cpu) | |
45 | { | |
46 | if (!cpu_possible(cpu)) | |
47 | return; | |
48 | ||
49 | switch (vcpu_online(cpu)) { | |
50 | case 1: | |
d68d82af | 51 | enable_hotplug_cpu(cpu); |
d745562c IC |
52 | break; |
53 | case 0: | |
d68d82af AN |
54 | (void)cpu_down(cpu); |
55 | disable_hotplug_cpu(cpu); | |
d745562c IC |
56 | break; |
57 | default: | |
58 | break; | |
d68d82af AN |
59 | } |
60 | } | |
61 | ||
62 | static void handle_vcpu_hotplug_event(struct xenbus_watch *watch, | |
63 | const char **vec, unsigned int len) | |
64 | { | |
65 | unsigned int cpu; | |
66 | char *cpustr; | |
67 | const char *node = vec[XS_WATCH_PATH]; | |
68 | ||
69 | cpustr = strstr(node, "cpu/"); | |
70 | if (cpustr != NULL) { | |
71 | sscanf(cpustr, "cpu/%u", &cpu); | |
72 | vcpu_hotplug(cpu); | |
73 | } | |
74 | } | |
75 | ||
76 | static int setup_cpu_watcher(struct notifier_block *notifier, | |
77 | unsigned long event, void *data) | |
78 | { | |
d745562c | 79 | int cpu; |
d68d82af AN |
80 | static struct xenbus_watch cpu_watch = { |
81 | .node = "cpu", | |
82 | .callback = handle_vcpu_hotplug_event}; | |
83 | ||
84 | (void)register_xenbus_watch(&cpu_watch); | |
85 | ||
d745562c IC |
86 | for_each_possible_cpu(cpu) { |
87 | if (vcpu_online(cpu) == 0) { | |
88 | (void)cpu_down(cpu); | |
89 | cpu_clear(cpu, cpu_present_map); | |
90 | } | |
91 | } | |
92 | ||
d68d82af AN |
93 | return NOTIFY_DONE; |
94 | } | |
95 | ||
96 | static int __init setup_vcpu_hotplug_event(void) | |
97 | { | |
98 | static struct notifier_block xsn_cpu = { | |
99 | .notifier_call = setup_cpu_watcher }; | |
100 | ||
5c51c637 | 101 | if (!xen_pv_domain()) |
d68d82af AN |
102 | return -ENODEV; |
103 | ||
104 | register_xenstore_notifier(&xsn_cpu); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | arch_initcall(setup_vcpu_hotplug_event); | |
110 |