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