sys/dev/hyperv/utilities/hv_timesync.c

   1 /*-
   2  * Copyright (c) 2014 Microsoft Corp.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 /*
  30  * A common driver for all hyper-V util services.
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/kernel.h>
  35 #include <sys/bus.h>
  36 #include <sys/malloc.h>
  37 #include <sys/module.h>
  38 #include <sys/reboot.h>
  39 #include <sys/timetc.h>
  40 #include <sys/syscallsubr.h>
  41
  42 #include <dev/hyperv/include/hyperv.h>
  43 #include "hv_util.h"
  44
  45 #define HV_WLTIMEDELTA              116444736000000000L     /* in 100ns unit */
  46 #define HV_ICTIMESYNCFLAG_PROBE     0
  47 #define HV_ICTIMESYNCFLAG_SYNC      1
  48 #define HV_ICTIMESYNCFLAG_SAMPLE    2
  49 #define HV_NANO_SEC_PER_SEC         1000000000
  50
  51 /* Time Sync data */
  52 typedef struct {
  53         uint64_t data;
  54 } time_sync_data;
  55
  56         /* Time Synch Service */
  57 static hv_guid service_guid = {.data =
  58         {0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
  59         0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf } };
  60
  61 struct hv_ictimesync_data {
  62         uint64_t    parenttime;
  63         uint64_t    childtime;
  64         uint64_t    roundtriptime;
  65         uint8_t     flags;
  66 } __packed;
  67
  68 typedef struct hv_timesync_sc {
  69         hv_util_sc      util_sc;
  70         struct task     task;
  71         time_sync_data  time_msg;
  72 } hv_timesync_sc;
  73
  74 /**
  75  * Set host time based on time sync message from host
  76  */
  77 static void
  78 hv_set_host_time(void *context, int pending)
  79 {
  80         hv_timesync_sc *softc = (hv_timesync_sc*)context;
  81         uint64_t hosttime = softc->time_msg.data;
  82         struct timespec guest_ts, host_ts;
  83         uint64_t host_tns;
  84         int64_t diff;
  85         int error;
  86
  87         host_tns = (hosttime - HV_WLTIMEDELTA) * 100;
  88         host_ts.tv_sec = (time_t)(host_tns/HV_NANO_SEC_PER_SEC);
  89         host_ts.tv_nsec = (long)(host_tns%HV_NANO_SEC_PER_SEC);
  90
  91         nanotime(&guest_ts);
  92
  93         diff = (int64_t)host_ts.tv_sec - (int64_t)guest_ts.tv_sec;
  94
  95         /*
  96          * If host differs by 5 seconds then make the guest catch up
  97          */
  98         if (diff > 5 || diff < -5) {
  99                 error = kern_clock_settime(curthread, CLOCK_REALTIME,
 100                     &host_ts);
 101         }
 102 }
 103
 104 /**
 105  * @brief Synchronize time with host after reboot, restore, etc.
 106  *
 107  * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
 108  * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
 109  * message after the timesync channel is opened. Since the hv_utils module is
 110  * loaded after hv_vmbus, the first message is usually missed. The other
 111  * thing is, systime is automatically set to emulated hardware clock which may
 112  * not be UTC time or in the same time zone. So, to override these effects, we
 113  * use the first 50 time samples for initial system time setting.
 114  */
 115 static inline
 116 void hv_adj_guesttime(hv_timesync_sc *sc, uint64_t hosttime, uint8_t flags)
 117 {
 118         sc->time_msg.data = hosttime;
 119
 120         if (((flags & HV_ICTIMESYNCFLAG_SYNC) != 0) ||
 121                 ((flags & HV_ICTIMESYNCFLAG_SAMPLE) != 0)) {
 122                 taskqueue_enqueue(taskqueue_thread, &sc->task);
 123         }
 124 }
 125
 126 /**
 127  * Time Sync Channel message handler
 128  */
 129 static void
 130 hv_timesync_cb(void *context)
 131 {
 132         hv_vmbus_channel*       channel;
 133         hv_vmbus_icmsg_hdr*     icmsghdrp;
 134         uint32_t                recvlen;
 135         uint64_t                requestId;
 136         int                     ret;
 137         uint8_t*                time_buf;
 138         struct hv_ictimesync_data* timedatap;
 139         hv_timesync_sc          *softc;
 140
 141         softc = (hv_timesync_sc*)context;
 142         channel = softc->util_sc.hv_dev->channel;
 143         time_buf = softc->util_sc.receive_buffer;
 144
 145         ret = hv_vmbus_channel_recv_packet(channel, time_buf,
 146                 PAGE_SIZE, &recvlen, &requestId);
 147
 148         if ((ret == 0) && recvlen > 0) {
 149             icmsghdrp = (struct hv_vmbus_icmsg_hdr *) &time_buf[
 150                 sizeof(struct hv_vmbus_pipe_hdr)];
 151
 152             if (icmsghdrp->icmsgtype == HV_ICMSGTYPE_NEGOTIATE) {
 153                 hv_negotiate_version(icmsghdrp, NULL, time_buf);
 154             } else {
 155                 timedatap = (struct hv_ictimesync_data *) &time_buf[
 156                     sizeof(struct hv_vmbus_pipe_hdr) +
 157                         sizeof(struct hv_vmbus_icmsg_hdr)];
 158                 hv_adj_guesttime(softc, timedatap->parenttime, timedatap->flags);
 159             }
 160
 161             icmsghdrp->icflags = HV_ICMSGHDRFLAG_TRANSACTION
 162                 | HV_ICMSGHDRFLAG_RESPONSE;
 163
 164             hv_vmbus_channel_send_packet(channel, time_buf,
 165                 recvlen, requestId,
 166                 HV_VMBUS_PACKET_TYPE_DATA_IN_BAND, 0);
 167         }
 168 }
 169
 170 static int
 171 hv_timesync_probe(device_t dev)
 172 {
 173         const char *p = vmbus_get_type(dev);
 174         if (!memcmp(p, &service_guid, sizeof(hv_guid))) {
 175                 device_set_desc(dev, "Hyper-V Time Synch Service");
 176                 return BUS_PROBE_DEFAULT;
 177         }
 178
 179         return ENXIO;
 180 }
 181
 182 static int
 183 hv_timesync_attach(device_t dev)
 184 {
 185         hv_timesync_sc *softc = device_get_softc(dev);
 186
 187         softc->util_sc.callback = hv_timesync_cb;
 188         TASK_INIT(&softc->task, 1, hv_set_host_time, softc);
 189
 190         return hv_util_attach(dev);
 191 }
 192
 193 static int
 194 hv_timesync_detach(device_t dev)
 195 {
 196         hv_timesync_sc *softc = device_get_softc(dev);
 197         taskqueue_drain(taskqueue_thread, &softc->task);
 198
 199         return hv_util_detach(dev);
 200 }
 201
 202 static device_method_t timesync_methods[] = {
 203         /* Device interface */
 204         DEVMETHOD(device_probe, hv_timesync_probe),
 205         DEVMETHOD(device_attach, hv_timesync_attach),
 206         DEVMETHOD(device_detach, hv_timesync_detach),
 207         { 0, 0 }
 208 };
 209
 210 static driver_t timesync_driver = { "hvtimesync", timesync_methods, sizeof(hv_timesync_sc)};
 211
 212 static devclass_t timesync_devclass;
 213
 214 DRIVER_MODULE(hv_timesync, vmbus, timesync_driver, timesync_devclass, NULL, NULL);
 215 MODULE_VERSION(hv_timesync, 1);
 216 MODULE_DEPEND(hv_timesync, vmbus, 1, 1, 1);