cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

tod-kvm.c (4656B)

      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/runstate.h"
     15#include "hw/s390x/tod.h"
     16#include "kvm/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, bool 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);