112 lines
2.0 KiB
C
112 lines
2.0 KiB
C
#include <linux/notifier.h>
|
|
|
|
#include <xen/xen.h>
|
|
#include <xen/xenbus.h>
|
|
|
|
#include <asm/xen/hypervisor.h>
|
|
#include <asm/cpu.h>
|
|
|
|
static void enable_hotplug_cpu(int cpu)
|
|
{
|
|
if (!cpu_present(cpu))
|
|
arch_register_cpu(cpu);
|
|
|
|
set_cpu_present(cpu, true);
|
|
}
|
|
|
|
static void disable_hotplug_cpu(int cpu)
|
|
{
|
|
if (cpu_present(cpu))
|
|
arch_unregister_cpu(cpu);
|
|
|
|
set_cpu_present(cpu, false);
|
|
}
|
|
|
|
static int vcpu_online(unsigned int cpu)
|
|
{
|
|
int err;
|
|
char dir[32], state[32];
|
|
|
|
sprintf(dir, "cpu/%u", cpu);
|
|
err = xenbus_scanf(XBT_NIL, dir, "availability", "%s", state);
|
|
if (err != 1) {
|
|
printk(KERN_ERR "XENBUS: Unable to read cpu state\n");
|
|
return err;
|
|
}
|
|
|
|
if (strcmp(state, "online") == 0)
|
|
return 1;
|
|
else if (strcmp(state, "offline") == 0)
|
|
return 0;
|
|
|
|
printk(KERN_ERR "XENBUS: unknown state(%s) on CPU%d\n", state, cpu);
|
|
return -EINVAL;
|
|
}
|
|
static void vcpu_hotplug(unsigned int cpu)
|
|
{
|
|
if (!cpu_possible(cpu))
|
|
return;
|
|
|
|
switch (vcpu_online(cpu)) {
|
|
case 1:
|
|
enable_hotplug_cpu(cpu);
|
|
break;
|
|
case 0:
|
|
(void)cpu_down(cpu);
|
|
disable_hotplug_cpu(cpu);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void handle_vcpu_hotplug_event(struct xenbus_watch *watch,
|
|
const char **vec, unsigned int len)
|
|
{
|
|
unsigned int cpu;
|
|
char *cpustr;
|
|
const char *node = vec[XS_WATCH_PATH];
|
|
|
|
cpustr = strstr(node, "cpu/");
|
|
if (cpustr != NULL) {
|
|
sscanf(cpustr, "cpu/%u", &cpu);
|
|
vcpu_hotplug(cpu);
|
|
}
|
|
}
|
|
|
|
static int setup_cpu_watcher(struct notifier_block *notifier,
|
|
unsigned long event, void *data)
|
|
{
|
|
int cpu;
|
|
static struct xenbus_watch cpu_watch = {
|
|
.node = "cpu",
|
|
.callback = handle_vcpu_hotplug_event};
|
|
|
|
(void)register_xenbus_watch(&cpu_watch);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
if (vcpu_online(cpu) == 0) {
|
|
(void)cpu_down(cpu);
|
|
set_cpu_present(cpu, false);
|
|
}
|
|
}
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static int __init setup_vcpu_hotplug_event(void)
|
|
{
|
|
static struct notifier_block xsn_cpu = {
|
|
.notifier_call = setup_cpu_watcher };
|
|
|
|
if (!xen_pv_domain())
|
|
return -ENODEV;
|
|
|
|
register_xenstore_notifier(&xsn_cpu);
|
|
|
|
return 0;
|
|
}
|
|
|
|
arch_initcall(setup_vcpu_hotplug_event);
|
|
|