LXR qemu/hw/s390x/tod-kvm.c

   1/*
   2 * TOD (Time Of Day) clock - KVM implementation
   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 "qapi/error.h"
  13#include "qemu/module.h"
  14#include "sysemu/sysemu.h"
  15#include "hw/s390x/tod.h"
  16#include "kvm_s390x.h"
  17
  18static void kvm_s390_get_tod_raw(S390TOD *tod, Error **errp)
  19{
  20    int r;
  21
  22    r = kvm_s390_get_clock_ext(&tod->high, &tod->low);
  23    if (r == -ENXIO) {
  24        r = kvm_s390_get_clock(&tod->high, &tod->low);
  25    }
  26    if (r) {
  27        error_setg(errp, "Unable to get KVM guest TOD clock: %s",
  28                   strerror(-r));
  29    }
  30}
  31
  32static void kvm_s390_tod_get(const S390TODState *td, S390TOD *tod, Error **errp)
  33{
  34    if (td->stopped) {
  35        *tod = td->base;
  36        return;
  37    }
  38
  39    kvm_s390_get_tod_raw(tod, errp);
  40}
  41
  42static void kvm_s390_set_tod_raw(const S390TOD *tod, Error **errp)
  43{
  44    int r;
  45
  46    r = kvm_s390_set_clock_ext(tod->high, tod->low);
  47    if (r == -ENXIO) {
  48        r = kvm_s390_set_clock(tod->high, tod->low);
  49    }
  50    if (r) {
  51        error_setg(errp, "Unable to set KVM guest TOD clock: %s",
  52                   strerror(-r));
  53    }
  54}
  55
  56static void kvm_s390_tod_set(S390TODState *td, const S390TOD *tod, Error **errp)
  57{
  58    Error *local_err = NULL;
  59
  60    /*
  61     * Somebody (e.g. migration) set the TOD. We'll store it into KVM to
  62     * properly detect errors now but take a look at the runstate to decide
  63     * whether really to keep the tod running. E.g. during migration, this
  64     * is the point where we want to stop the initially running TOD to fire
  65     * it back up when actually starting the migrated guest.
  66     */
  67    kvm_s390_set_tod_raw(tod, &local_err);
  68    if (local_err) {
  69        error_propagate(errp, local_err);
  70        return;
  71    }
  72
  73    if (runstate_is_running()) {
  74        td->stopped = false;
  75    } else {
  76        td->stopped = true;
  77        td->base = *tod;
  78    }
  79}
  80
  81static void kvm_s390_tod_vm_state_change(void *opaque, int running,
  82                                         RunState state)
  83{
  84    S390TODState *td = opaque;
  85    Error *local_err = NULL;
  86
  87    if (running && td->stopped) {
  88        /* Set the old TOD when running the VM - start the TOD clock. */
  89        kvm_s390_set_tod_raw(&td->base, &local_err);
  90        if (local_err) {
  91            warn_report_err(local_err);
  92        }
  93        /* Treat errors like the TOD was running all the time. */
  94        td->stopped = false;
  95    } else if (!running && !td->stopped) {
  96        /* Store the TOD when stopping the VM - stop the TOD clock. */
  97        kvm_s390_get_tod_raw(&td->base, &local_err);
  98        if (local_err) {
  99            /* Keep the TOD running in case we could not back it up. */
 100            warn_report_err(local_err);
 101        } else {
 102            td->stopped = true;
 103        }
 104    }
 105}
 106
 107static void kvm_s390_tod_realize(DeviceState *dev, Error **errp)
 108{
 109    S390TODState *td = S390_TOD(dev);
 110    S390TODClass *tdc = S390_TOD_GET_CLASS(td);
 111    Error *local_err = NULL;
 112
 113    tdc->parent_realize(dev, &local_err);
 114    if (local_err) {
 115        error_propagate(errp, local_err);
 116        return;
 117    }
 118
 119    /*
 120     * We need to know when the VM gets started/stopped to start/stop the TOD.
 121     * As we can never have more than one TOD instance (and that will never be
 122     * removed), registering here and never unregistering is good enough.
 123     */
 124    qemu_add_vm_change_state_handler(kvm_s390_tod_vm_state_change, td);
 125}
 126
 127static void kvm_s390_tod_class_init(ObjectClass *oc, void *data)
 128{
 129    S390TODClass *tdc = S390_TOD_CLASS(oc);
 130
 131    device_class_set_parent_realize(DEVICE_CLASS(oc), kvm_s390_tod_realize,
 132                                    &tdc->parent_realize);
 133    tdc->get = kvm_s390_tod_get;
 134    tdc->set = kvm_s390_tod_set;
 135}
 136
 137static void kvm_s390_tod_init(Object *obj)
 138{
 139    S390TODState *td = S390_TOD(obj);
 140
 141    /*
 142     * The TOD is initially running (value stored in KVM). Avoid needless
 143     * loading/storing of the TOD when starting a simple VM, so let it
 144     * run although the (never started) VM is stopped. For migration, we
 145     * will properly set the TOD later.
 146     */
 147    td->stopped = false;
 148}
 149
 150static TypeInfo kvm_s390_tod_info = {
 151    .name = TYPE_KVM_S390_TOD,
 152    .parent = TYPE_S390_TOD,
 153    .instance_size = sizeof(S390TODState),
 154    .instance_init = kvm_s390_tod_init,
 155    .class_init = kvm_s390_tod_class_init,
 156    .class_size = sizeof(S390TODClass),
 157};
 158
 159static void register_types(void)
 160{
 161    type_register_static(&kvm_s390_tod_info);
 162}
 163type_init(register_types);
 164