hw/i386/kvm/clock.c

   1 /*
   2  * QEMU KVM support, paravirtual clock device
   3  *
   4  * Copyright (C) 2011 Siemens AG
   5  *
   6  * Authors:
   7  *  Jan Kiszka        <jan.kiszka@siemens.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL version 2.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu-common.h"
  17 #include "sysemu/sysemu.h"
  18 #include "sysemu/kvm.h"
  19 #include "hw/sysbus.h"
  20 #include "hw/kvm/clock.h"
  21
  22 #include <linux/kvm.h>
  23 #include <linux/kvm_para.h>
  24
  25 #define TYPE_KVM_CLOCK "kvmclock"
  26 #define KVM_CLOCK(obj) OBJECT_CHECK(KVMClockState, (obj), TYPE_KVM_CLOCK)
  27
  28 typedef struct KVMClockState {
  29     /*< private >*/
  30     SysBusDevice busdev;
  31     /*< public >*/
  32
  33     uint64_t clock;
  34     bool clock_valid;
  35 } KVMClockState;
  36
  37
  38 static void kvmclock_vm_state_change(void *opaque, int running,
  39                                      RunState state)
  40 {
  41     KVMClockState *s = opaque;
  42     CPUState *cpu;
  43     int cap_clock_ctrl = kvm_check_extension(kvm_state, KVM_CAP_KVMCLOCK_CTRL);
  44     int ret;
  45
  46     if (running) {
  47         struct kvm_clock_data data;
  48
  49         s->clock_valid = false;
  50
  51         data.clock = s->clock;
  52         data.flags = 0;
  53         ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
  54         if (ret < 0) {
  55             fprintf(stderr, "KVM_SET_CLOCK failed: %s\n", strerror(ret));
  56             abort();
  57         }
  58
  59         if (!cap_clock_ctrl) {
  60             return;
  61         }
  62         CPU_FOREACH(cpu) {
  63             ret = kvm_vcpu_ioctl(cpu, KVM_KVMCLOCK_CTRL, 0);
  64             if (ret) {
  65                 if (ret != -EINVAL) {
  66                     fprintf(stderr, "%s: %s\n", __func__, strerror(-ret));
  67                 }
  68                 return;
  69             }
  70         }
  71     } else {
  72         struct kvm_clock_data data;
  73         int ret;
  74
  75         if (s->clock_valid) {
  76             return;
  77         }
  78         ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
  79         if (ret < 0) {
  80             fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
  81             abort();
  82         }
  83         s->clock = data.clock;
  84
  85         /*
  86          * If the VM is stopped, declare the clock state valid to
  87          * avoid re-reading it on next vmsave (which would return
  88          * a different value). Will be reset when the VM is continued.
  89          */
  90         s->clock_valid = true;
  91     }
  92 }
  93
  94 static void kvmclock_realize(DeviceState *dev, Error **errp)
  95 {
  96     KVMClockState *s = KVM_CLOCK(dev);
  97
  98     qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
  99 }
 100
 101 static const VMStateDescription kvmclock_vmsd = {
 102     .name = "kvmclock",
 103     .version_id = 1,
 104     .minimum_version_id = 1,
 105     .minimum_version_id_old = 1,
 106     .fields = (VMStateField[]) {
 107         VMSTATE_UINT64(clock, KVMClockState),
 108         VMSTATE_END_OF_LIST()
 109     }
 110 };
 111
 112 static void kvmclock_class_init(ObjectClass *klass, void *data)
 113 {
 114     DeviceClass *dc = DEVICE_CLASS(klass);
 115
 116     dc->realize = kvmclock_realize;
 117     dc->vmsd = &kvmclock_vmsd;
 118 }
 119
 120 static const TypeInfo kvmclock_info = {
 121     .name          = TYPE_KVM_CLOCK,
 122     .parent        = TYPE_SYS_BUS_DEVICE,
 123     .instance_size = sizeof(KVMClockState),
 124     .class_init    = kvmclock_class_init,
 125 };
 126
 127 /* Note: Must be called after VCPU initialization. */
 128 void kvmclock_create(void)
 129 {
 130     X86CPU *cpu = X86_CPU(first_cpu);
 131
 132     if (kvm_enabled() &&
 133         cpu->env.features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |
 134                                        (1ULL << KVM_FEATURE_CLOCKSOURCE2))) {
 135         sysbus_create_simple(TYPE_KVM_CLOCK, -1, NULL);
 136     }
 137 }
 138
 139 static void kvmclock_register_types(void)
 140 {
 141     type_register_static(&kvmclock_info);
 142 }
 143
 144 type_init(kvmclock_register_types)