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 17 static 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 31 static 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 41 static 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 55 static 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 80 static 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 } 105 106 static 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 } 125 126 static 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 } 135 136 static 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 } 148 149 static 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 }; 157 158 static void register_types(void) 159 { 160 type_register_static(&kvm_s390_tod_info); 161 } 162 type_init(register_types); 163