1 #include <linux/notifier.h>
3 #include <xen/xenbus.h>
5 #include <asm/xen/hypervisor.h>
8 static void enable_hotplug_cpu(int cpu
)
10 if (!cpu_present(cpu
))
11 arch_register_cpu(cpu
);
13 cpu_set(cpu
, cpu_present_map
);
16 static void disable_hotplug_cpu(int cpu
)
19 arch_unregister_cpu(cpu
);
21 cpu_clear(cpu
, cpu_present_map
);
24 static int vcpu_online(unsigned int cpu
)
27 char dir
[32], state
[32];
29 sprintf(dir
, "cpu/%u", cpu
);
30 err
= xenbus_scanf(XBT_NIL
, dir
, "availability", "%s", state
);
32 printk(KERN_ERR
"XENBUS: Unable to read cpu state\n");
36 if (strcmp(state
, "online") == 0)
38 else if (strcmp(state
, "offline") == 0)
41 printk(KERN_ERR
"XENBUS: unknown state(%s) on CPU%d\n", state
, cpu
);
44 static void vcpu_hotplug(unsigned int cpu
)
46 if (!cpu_possible(cpu
))
49 switch (vcpu_online(cpu
)) {
51 enable_hotplug_cpu(cpu
);
55 disable_hotplug_cpu(cpu
);
62 static void handle_vcpu_hotplug_event(struct xenbus_watch
*watch
,
63 const char **vec
, unsigned int len
)
67 const char *node
= vec
[XS_WATCH_PATH
];
69 cpustr
= strstr(node
, "cpu/");
71 sscanf(cpustr
, "cpu/%u", &cpu
);
76 static int setup_cpu_watcher(struct notifier_block
*notifier
,
77 unsigned long event
, void *data
)
80 static struct xenbus_watch cpu_watch
= {
82 .callback
= handle_vcpu_hotplug_event
};
84 (void)register_xenbus_watch(&cpu_watch
);
86 for_each_possible_cpu(cpu
) {
87 if (vcpu_online(cpu
) == 0) {
89 cpu_clear(cpu
, cpu_present_map
);
96 static int __init
setup_vcpu_hotplug_event(void)
98 static struct notifier_block xsn_cpu
= {
99 .notifier_call
= setup_cpu_watcher
};
101 if (!xen_pv_domain())
104 register_xenstore_notifier(&xsn_cpu
);
109 arch_initcall(setup_vcpu_hotplug_event
);