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 18 static 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 32 static 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 42 static 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 56 static 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 81 static 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 } 106 107 static 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 } 126 127 static 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 } 136 137 static 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 } 149 150 static 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 }; 158 159 static void register_types(void) 160 { 161 type_register_static(&kvm_s390_tod_info); 162 } 163 type_init(register_types); 164