hw/s390x/tod.c

   1 /*
   2  * TOD (Time Of Day) clock
   3  *
   4  * Copyright 2018 Red Hat, Inc.
   5  * Author(s): David Hildenbrand <david@redhat.com>
   6  *
   7  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   8  * See the COPYING file in the top-level directory.
   9  */
  10
  11 #include "qemu/osdep.h"
  12 #include "hw/s390x/tod.h"
  13 #include "qapi/error.h"
  14 #include "qemu/error-report.h"
  15 #include "qemu/module.h"
  16 #include "sysemu/kvm.h"
  17 #include "sysemu/tcg.h"
  18 #include "sysemu/qtest.h"
  19 #include "migration/qemu-file-types.h"
  20 #include "migration/register.h"
  21
  22 void s390_init_tod(void)
  23 {
  24     Object *obj;
  25
  26     if (kvm_enabled()) {
  27         obj = object_new(TYPE_KVM_S390_TOD);
  28     } else if (tcg_enabled()) {
  29         obj = object_new(TYPE_QEMU_S390_TOD);
  30     } else if (qtest_enabled()) {
  31         return;
  32     } else {
  33         error_report("current accelerator not handled in s390_init_tod!");
  34         abort();
  35     }
  36     object_property_add_child(qdev_get_machine(), TYPE_S390_TOD, obj);
  37     object_unref(obj);
  38
  39     qdev_realize(DEVICE(obj), NULL, &error_fatal);
  40 }
  41
  42 S390TODState *s390_get_todstate(void)
  43 {
  44     static S390TODState *ts;
  45
  46     if (!ts) {
  47         ts = S390_TOD(object_resolve_path_type("", TYPE_S390_TOD, NULL));
  48     }
  49
  50     return ts;
  51 }
  52
  53 #define S390_TOD_CLOCK_VALUE_MISSING    0x00
  54 #define S390_TOD_CLOCK_VALUE_PRESENT    0x01
  55
  56 static void s390_tod_save(QEMUFile *f, void *opaque)
  57 {
  58     S390TODState *td = opaque;
  59     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
  60     Error *err = NULL;
  61     S390TOD tod;
  62
  63     tdc->get(td, &tod, &err);
  64     if (err) {
  65         warn_report_err(err);
  66         error_printf("Guest clock will not be migrated "
  67                      "which could cause the guest to hang.");
  68         qemu_put_byte(f, S390_TOD_CLOCK_VALUE_MISSING);
  69         return;
  70     }
  71
  72     qemu_put_byte(f, S390_TOD_CLOCK_VALUE_PRESENT);
  73     qemu_put_byte(f, tod.high);
  74     qemu_put_be64(f, tod.low);
  75 }
  76
  77 static int s390_tod_load(QEMUFile *f, void *opaque, int version_id)
  78 {
  79     S390TODState *td = opaque;
  80     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
  81     Error *err = NULL;
  82     S390TOD tod;
  83
  84     if (qemu_get_byte(f) == S390_TOD_CLOCK_VALUE_MISSING) {
  85         warn_report("Guest clock was not migrated. This could "
  86                     "cause the guest to hang.");
  87         return 0;
  88     }
  89
  90     tod.high = qemu_get_byte(f);
  91     tod.low = qemu_get_be64(f);
  92
  93     tdc->set(td, &tod, &err);
  94     if (err) {
  95         error_report_err(err);
  96         return -1;
  97     }
  98     return 0;
  99 }
 100
 101 static SaveVMHandlers savevm_tod = {
 102     .save_state = s390_tod_save,
 103     .load_state = s390_tod_load,
 104 };
 105
 106 static void s390_tod_realize(DeviceState *dev, Error **errp)
 107 {
 108     S390TODState *td = S390_TOD(dev);
 109
 110     /* Legacy migration interface */
 111     register_savevm_live("todclock", 0, 1, &savevm_tod, td);
 112 }
 113
 114 static void s390_tod_class_init(ObjectClass *oc, void *data)
 115 {
 116     DeviceClass *dc = DEVICE_CLASS(oc);
 117
 118     dc->desc = "TOD (Time Of Day) Clock";
 119     dc->realize = s390_tod_realize;
 120     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 121
 122     /* We only have one TOD clock in the system attached to the machine */
 123     dc->user_creatable = false;
 124 }
 125
 126 static TypeInfo s390_tod_info = {
 127     .name = TYPE_S390_TOD,
 128     .parent = TYPE_DEVICE,
 129     .instance_size = sizeof(S390TODState),
 130     .class_init = s390_tod_class_init,
 131     .class_size = sizeof(S390TODClass),
 132     .abstract = true,
 133 };
 134
 135 static void register_types(void)
 136 {
 137     type_register_static(&s390_tod_info);
 138 }
 139 type_init(register_types);