| | 1 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
| | 2 | |
| | 3 | #include <linux/notifier.h> |
| | 4 | |
| | 5 | #include <xen/xen.h> |
| | 6 | #include <xen/xenbus.h> |
| | 7 | |
| | 8 | #include <asm/xen/hypervisor.h> |
| | 9 | #include <asm/cpu.h> |
| | 10 | |
| | 11 | static void enable_hotplug_cpu(int cpu) |
| | 12 | { |
| | 13 | if (!cpu_present(cpu)) |
| | 14 | arch_register_cpu(cpu); |
| | 15 | |
| | 16 | set_cpu_present(cpu, true); |
| | 17 | } |
| | 18 | |
| | 19 | static void disable_hotplug_cpu(int cpu) |
| | 20 | { |
| | 21 | if (cpu_present(cpu)) |
| | 22 | arch_unregister_cpu(cpu); |
| | 23 | |
| | 24 | set_cpu_present(cpu, false); |
| | 25 | } |
| | 26 | |
| | 27 | static int vcpu_online(unsigned int cpu) |
| | 28 | { |
| | 29 | int err; |
| | 30 | char dir[16], state[16]; |
| | 31 | |
| | 32 | sprintf(dir, "cpu/%u", cpu); |
| | 33 | err = xenbus_scanf(XBT_NIL, dir, "availability", "%15s", state); |
| | 34 | if (err != 1) { |
| | 35 | if (!xen_initial_domain()) |
| | 36 | pr_err("Unable to read cpu state\n"); |
| | 37 | return err; |
| | 38 | } |
| | 39 | |
| | 40 | if (strcmp(state, "online") == 0) |
| | 41 | return 1; |
| | 42 | else if (strcmp(state, "offline") == 0) |
| | 43 | return 0; |
| | 44 | |
| | 45 | pr_err("unknown state(%s) on CPU%d\n", state, cpu); |
| | 46 | return -EINVAL; |
| | 47 | } |
| | 48 | static void vcpu_hotplug(unsigned int cpu) |
| | 49 | { |
| | 50 | if (!cpu_possible(cpu)) |
| | 51 | return; |
| | 52 | |
| | 53 | switch (vcpu_online(cpu)) { |
| | 54 | case 1: |
| | 55 | enable_hotplug_cpu(cpu); |
| | 56 | break; |
| | 57 | case 0: |
| | 58 | (void)cpu_down(cpu); |
| | 59 | disable_hotplug_cpu(cpu); |
| | 60 | break; |
| | 61 | default: |
| | 62 | break; |
| | 63 | } |
| | 64 | } |
| | 65 | |
| | 66 | static void handle_vcpu_hotplug_event(struct xenbus_watch *watch, |
| | 67 | const char **vec, unsigned int len) |
| | 68 | { |
| | 69 | unsigned int cpu; |
| | 70 | char *cpustr; |
| | 71 | const char *node = vec[XS_WATCH_PATH]; |
| | 72 | |
| | 73 | cpustr = strstr(node, "cpu/"); |
| | 74 | if (cpustr != NULL) { |
| | 75 | sscanf(cpustr, "cpu/%u", &cpu); |
| | 76 | vcpu_hotplug(cpu); |
| | 77 | } |
| | 78 | } |
| | 79 | |
| | 80 | static int setup_cpu_watcher(struct notifier_block *notifier, |
| | 81 | unsigned long event, void *data) |
| | 82 | { |
| | 83 | int cpu; |
| | 84 | static struct xenbus_watch cpu_watch = { |
| | 85 | .node = "cpu", |
| | 86 | .callback = handle_vcpu_hotplug_event}; |
| | 87 | |
| | 88 | (void)register_xenbus_watch(&cpu_watch); |
| | 89 | |
| | 90 | for_each_possible_cpu(cpu) { |
| | 91 | if (vcpu_online(cpu) == 0) { |
| | 92 | (void)cpu_down(cpu); |
| | 93 | set_cpu_present(cpu, false); |
| | 94 | } |
| | 95 | } |
| | 96 | |
| | 97 | return NOTIFY_DONE; |
| | 98 | } |
| | 99 | |
| | 100 | static int __init setup_vcpu_hotplug_event(void) |
| | 101 | { |
| | 102 | static struct notifier_block xsn_cpu = { |
| | 103 | .notifier_call = setup_cpu_watcher }; |
| | 104 | |
| | 105 | if (!xen_pv_domain()) |
| | 106 | return -ENODEV; |
| | 107 | |
| | 108 | register_xenstore_notifier(&xsn_cpu); |
| | 109 | |
| | 110 | return 0; |
| | 111 | } |
| | 112 | |
| | 113 | arch_initcall(setup_vcpu_hotplug_event); |
| | 114 | |
projects / linux-2.6-block.git / blame_incremental