qemu

tod-kvm.c (4850B)

---

 /*
  * TOD (Time Of Day) clock - KVM implementation
  *
  * Copyright 2018 Red Hat, Inc.
  * Author(s): David Hildenbrand <david@redhat.com>
  *
  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  * See the COPYING file in the top-level directory.
  */
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu/module.h"
 #include "sysemu/runstate.h"
 #include "hw/s390x/tod.h"
 #include "hw/s390x/pv.h"
 #include "kvm/kvm_s390x.h"
 
 static void kvm_s390_get_tod_raw(S390TOD *tod, Error **errp)
 {
     int r;
 
     r = kvm_s390_get_clock_ext(&tod->high, &tod->low);
     if (r == -ENXIO) {
         r = kvm_s390_get_clock(&tod->high, &tod->low);
     }
     if (r) {
         error_setg(errp, "Unable to get KVM guest TOD clock: %s",
                    strerror(-r));
     }
 }
 
 static void kvm_s390_tod_get(const S390TODState *td, S390TOD *tod, Error **errp)
 {
     if (td->stopped) {
         *tod = td->base;
         return;
     }
 
     kvm_s390_get_tod_raw(tod, errp);
 }
 
 static void kvm_s390_set_tod_raw(const S390TOD *tod, Error **errp)
 {
     int r;
 
     r = kvm_s390_set_clock_ext(tod->high, tod->low);
     if (r == -ENXIO) {
         r = kvm_s390_set_clock(tod->high, tod->low);
     }
     if (r) {
         error_setg(errp, "Unable to set KVM guest TOD clock: %s",
                    strerror(-r));
     }
 }
 
 static void kvm_s390_tod_set(S390TODState *td, const S390TOD *tod, Error **errp)
 {
     Error *local_err = NULL;
 
     /*
      * Somebody (e.g. migration) set the TOD. We'll store it into KVM to
      * properly detect errors now but take a look at the runstate to decide
      * whether really to keep the tod running. E.g. during migration, this
      * is the point where we want to stop the initially running TOD to fire
      * it back up when actually starting the migrated guest.
      */
     kvm_s390_set_tod_raw(tod, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
     }
 
     if (runstate_is_running()) {
         td->stopped = false;
     } else {
         td->stopped = true;
         td->base = *tod;
     }
 }
 
 static void kvm_s390_tod_vm_state_change(void *opaque, bool running,
                                          RunState state)
 {
     S390TODState *td = opaque;
     Error *local_err = NULL;
 
     /*
      * Under PV, the clock is under ultravisor control, hence we cannot restore
      * it on resume.
      */
     if (s390_is_pv()) {
         return;
     }
 
     if (running && td->stopped) {
         /* Set the old TOD when running the VM - start the TOD clock. */
         kvm_s390_set_tod_raw(&td->base, &local_err);
         if (local_err) {
             warn_report_err(local_err);
         }
         /* Treat errors like the TOD was running all the time. */
         td->stopped = false;
     } else if (!running && !td->stopped) {
         /* Store the TOD when stopping the VM - stop the TOD clock. */
         kvm_s390_get_tod_raw(&td->base, &local_err);
         if (local_err) {
             /* Keep the TOD running in case we could not back it up. */
             warn_report_err(local_err);
         } else {
             td->stopped = true;
         }
     }
 }
 
 static void kvm_s390_tod_realize(DeviceState *dev, Error **errp)
 {
     S390TODState *td = S390_TOD(dev);
     S390TODClass *tdc = S390_TOD_GET_CLASS(td);
     Error *local_err = NULL;
 
     tdc->parent_realize(dev, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
     }
 
     /*
      * We need to know when the VM gets started/stopped to start/stop the TOD.
      * As we can never have more than one TOD instance (and that will never be
      * removed), registering here and never unregistering is good enough.
      */
     qemu_add_vm_change_state_handler(kvm_s390_tod_vm_state_change, td);
 }
 
 static void kvm_s390_tod_class_init(ObjectClass *oc, void *data)
 {
     S390TODClass *tdc = S390_TOD_CLASS(oc);
 
     device_class_set_parent_realize(DEVICE_CLASS(oc), kvm_s390_tod_realize,
                                     &tdc->parent_realize);
     tdc->get = kvm_s390_tod_get;
     tdc->set = kvm_s390_tod_set;
 }
 
 static void kvm_s390_tod_init(Object *obj)
 {
     S390TODState *td = S390_TOD(obj);
 
     /*
      * The TOD is initially running (value stored in KVM). Avoid needless
      * loading/storing of the TOD when starting a simple VM, so let it
      * run although the (never started) VM is stopped. For migration, we
      * will properly set the TOD later.
      */
     td->stopped = false;
 }
 
 static const TypeInfo kvm_s390_tod_info = {
     .name = TYPE_KVM_S390_TOD,
     .parent = TYPE_S390_TOD,
     .instance_size = sizeof(S390TODState),
     .instance_init = kvm_s390_tod_init,
     .class_init = kvm_s390_tod_class_init,
     .class_size = sizeof(S390TODClass),
 };
 
 static void register_types(void)
 {
     type_register_static(&kvm_s390_tod_info);
 }
 type_init(register_types);