Commit | Line | Data |
---|---|---|
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 | ||
13 | cpu_set(cpu, cpu_present_map); | |
14 | } | |
15 | ||
16 | static void disable_hotplug_cpu(int cpu) | |
17 | { | |
18 | if (cpu_present(cpu)) | |
19 | arch_unregister_cpu(cpu); | |
20 | ||
21 | cpu_clear(cpu, cpu_present_map); | |
22 | } | |
23 | ||
24 | static void vcpu_hotplug(unsigned int cpu) | |
25 | { | |
26 | int err; | |
27 | char dir[32], state[32]; | |
28 | ||
29 | if (!cpu_possible(cpu)) | |
30 | return; | |
31 | ||
32 | sprintf(dir, "cpu/%u", cpu); | |
33 | err = xenbus_scanf(XBT_NIL, dir, "availability", "%s", state); | |
34 | if (err != 1) { | |
35 | printk(KERN_ERR "XENBUS: Unable to read cpu state\n"); | |
36 | return; | |
37 | } | |
38 | ||
39 | if (strcmp(state, "online") == 0) { | |
40 | enable_hotplug_cpu(cpu); | |
41 | } else if (strcmp(state, "offline") == 0) { | |
42 | (void)cpu_down(cpu); | |
43 | disable_hotplug_cpu(cpu); | |
44 | } else { | |
45 | printk(KERN_ERR "XENBUS: unknown state(%s) on CPU%d\n", | |
46 | state, cpu); | |
47 | } | |
48 | } | |
49 | ||
50 | static void handle_vcpu_hotplug_event(struct xenbus_watch *watch, | |
51 | const char **vec, unsigned int len) | |
52 | { | |
53 | unsigned int cpu; | |
54 | char *cpustr; | |
55 | const char *node = vec[XS_WATCH_PATH]; | |
56 | ||
57 | cpustr = strstr(node, "cpu/"); | |
58 | if (cpustr != NULL) { | |
59 | sscanf(cpustr, "cpu/%u", &cpu); | |
60 | vcpu_hotplug(cpu); | |
61 | } | |
62 | } | |
63 | ||
64 | static int setup_cpu_watcher(struct notifier_block *notifier, | |
65 | unsigned long event, void *data) | |
66 | { | |
67 | static struct xenbus_watch cpu_watch = { | |
68 | .node = "cpu", | |
69 | .callback = handle_vcpu_hotplug_event}; | |
70 | ||
71 | (void)register_xenbus_watch(&cpu_watch); | |
72 | ||
73 | return NOTIFY_DONE; | |
74 | } | |
75 | ||
76 | static int __init setup_vcpu_hotplug_event(void) | |
77 | { | |
78 | static struct notifier_block xsn_cpu = { | |
79 | .notifier_call = setup_cpu_watcher }; | |
80 | ||
5c51c637 | 81 | if (!xen_pv_domain()) |
d68d82af AN |
82 | return -ENODEV; |
83 | ||
84 | register_xenstore_notifier(&xsn_cpu); | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | arch_initcall(setup_vcpu_hotplug_event); | |
90 |