[linux-2.6-block.git] / drivers / xen / cpu_hotplug.c

#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt

#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))
		xen_arch_register_cpu(cpu);

	set_cpu_present(cpu, true);
}

static void disable_hotplug_cpu(int cpu)
{
	if (cpu_online(cpu)) {
		lock_device_hotplug();
		device_offline(get_cpu_device(cpu));
		unlock_device_hotplug();
	}
	if (cpu_present(cpu))
		xen_arch_unregister_cpu(cpu);

	set_cpu_present(cpu, false);
}

static int vcpu_online(unsigned int cpu)
{
	int err;
	char dir[16], state[16];

	sprintf(dir, "cpu/%u", cpu);
	err = xenbus_scanf(XBT_NIL, dir, "availability", "%15s", state);
	if (err != 1) {
		if (!xen_initial_domain())
			pr_err("Unable to read cpu state\n");
		return err;
	}

	if (strcmp(state, "online") == 0)
		return 1;
	else if (strcmp(state, "offline") == 0)
		return 0;

	pr_err("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:
		disable_hotplug_cpu(cpu);
		break;
	default:
		break;
	}
}

static void handle_vcpu_hotplug_event(struct xenbus_watch *watch,
				      const char *path, const char *token)
{
	unsigned int cpu;
	char *cpustr;

	cpustr = strstr(path, "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 };

#ifdef CONFIG_X86
	if (!xen_pv_domain() && !xen_pvh_domain())
#else
	if (!xen_domain())
#endif
		return -ENODEV;

	register_xenstore_notifier(&xsn_cpu);

	return 0;
}

arch_initcall(setup_vcpu_hotplug_event);
Commit	Line	Data
283c0972 JP	1	#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
283c0972 JP	2
d68d82af AN	3	#include <linux/notifier.h>
d68d82af AN	4
1ccbf534	5	#include <xen/xen.h>
d68d82af AN	6	#include <xen/xenbus.h>
d68d82af AN	7
bb898558	8	#include <asm/xen/hypervisor.h>
d68d82af AN	9	#include <asm/cpu.h>
	10
	11	static void enable_hotplug_cpu(int cpu)
	12	{
	13	if (!cpu_present(cpu))
a314e3eb	14	xen_arch_register_cpu(cpu);
d68d82af	15
d680eb8b	16	set_cpu_present(cpu, true);
d68d82af AN	17	}
	18
	19	static void disable_hotplug_cpu(int cpu)
	20	{
1c7a6213 SS	21	if (cpu_online(cpu)) {
	22	lock_device_hotplug();
	23	device_offline(get_cpu_device(cpu));
	24	unlock_device_hotplug();
	25	}
d68d82af	26	if (cpu_present(cpu))
a314e3eb	27	xen_arch_unregister_cpu(cpu);
d68d82af	28
d680eb8b	29	set_cpu_present(cpu, false);
d68d82af AN	30	}
d68d82af AN	31
d745562c	32	static int vcpu_online(unsigned int cpu)
d68d82af AN	33	{
d68d82af AN	34	int err;
e5c702d3	35	char dir[16], state[16];
d68d82af	36
d68d82af	37	sprintf(dir, "cpu/%u", cpu);
e5c702d3	38	err = xenbus_scanf(XBT_NIL, dir, "availability", "%15s", state);
d68d82af	39	if (err != 1) {
5b02aa1e	40	if (!xen_initial_domain())
283c0972	41	pr_err("Unable to read cpu state\n");
d745562c	42	return err;
d68d82af AN	43	}
d68d82af AN	44
d745562c IC	45	if (strcmp(state, "online") == 0)
	46	return 1;
	47	else if (strcmp(state, "offline") == 0)
	48	return 0;
	49
283c0972	50	pr_err("unknown state(%s) on CPU%d\n", state, cpu);
d745562c IC	51	return -EINVAL;
	52	}
	53	static void vcpu_hotplug(unsigned int cpu)
	54	{
	55	if (!cpu_possible(cpu))
	56	return;
	57
	58	switch (vcpu_online(cpu)) {
	59	case 1:
d68d82af	60	enable_hotplug_cpu(cpu);
d745562c IC	61	break;
d745562c IC	62	case 0:
d68d82af	63	disable_hotplug_cpu(cpu);
d745562c IC	64	break;
	65	default:
	66	break;
d68d82af AN	67	}
	68	}
	69
	70	static void handle_vcpu_hotplug_event(struct xenbus_watch *watch,
5584ea25	71	const char path, const char token)
d68d82af AN	72	{
	73	unsigned int cpu;
	74	char *cpustr;
d68d82af	75
5584ea25	76	cpustr = strstr(path, "cpu/");
d68d82af AN	77	if (cpustr != NULL) {
	78	sscanf(cpustr, "cpu/%u", &cpu);
	79	vcpu_hotplug(cpu);
	80	}
	81	}
	82
	83	static int setup_cpu_watcher(struct notifier_block *notifier,
	84	unsigned long event, void *data)
	85	{
d745562c	86	int cpu;
d68d82af AN	87	static struct xenbus_watch cpu_watch = {
	88	.node = "cpu",
	89	.callback = handle_vcpu_hotplug_event};
	90
	91	(void)register_xenbus_watch(&cpu_watch);
	92
d745562c IC	93	for_each_possible_cpu(cpu) {
	94	if (vcpu_online(cpu) == 0) {
	95	(void)cpu_down(cpu);
d7d3756c	96	set_cpu_present(cpu, false);
d745562c IC	97	}
	98	}
	99
d68d82af AN	100	return NOTIFY_DONE;
	101	}
	102
	103	static int __init setup_vcpu_hotplug_event(void)
	104	{
	105	static struct notifier_block xsn_cpu = {
	106	.notifier_call = setup_cpu_watcher };
	107
a314e3eb	108	#ifdef CONFIG_X86
2a7197f0	109	if (!xen_pv_domain() && !xen_pvh_domain())
a314e3eb SS	110	#else
	111	if (!xen_domain())
	112	#endif
d68d82af AN	113	return -ENODEV;
	114
	115	register_xenstore_notifier(&xsn_cpu);
	116
	117	return 0;
	118	}
	119
	120	arch_initcall(setup_vcpu_hotplug_event);
	121