mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-22 00:40:03 +00:00
![Stefano Stabellini](/assets/img/avatar_default.png)
When offlining a cpu, instead of cpu_down, call device_offline, which also takes care of updating the cpu.dev.offline field. This keeps the sysfs file /sys/devices/system/cpu/cpuN/online, up to date. Also move the call to disable_hotplug_cpu, because it makes more sense to have it there. We don't call device_online at cpu-hotplug time, because that would immediately take the cpu online, while we want to retain the current behaviour: the user needs to explicitly enable the cpu after it has been hotplugged. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> CC: konrad.wilk@oracle.com CC: boris.ostrovsky@oracle.com CC: david.vrabel@citrix.com
122 lines
2.2 KiB
C
122 lines
2.2 KiB
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 **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 };
|
|
|
|
#ifdef CONFIG_X86
|
|
if (!xen_pv_domain())
|
|
#else
|
|
if (!xen_domain())
|
|
#endif
|
|
return -ENODEV;
|
|
|
|
register_xenstore_notifier(&xsn_cpu);
|
|
|
|
return 0;
|
|
}
|
|
|
|
arch_initcall(setup_vcpu_hotplug_event);
|
|
|