sys/dev/hyperv/utilities/hv_timesync.c

   1 /*-
   2  * Copyright (c) 2014,2016 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 <dev/hyperv/include/vmbus.h>
  44 #include "hv_util.h"
  45 #include "vmbus_if.h"
  46
  47 #define HV_WLTIMEDELTA              116444736000000000L     /* in 100ns unit */
  48 #define HV_ICTIMESYNCFLAG_PROBE     0
  49 #define HV_ICTIMESYNCFLAG_SYNC      1
  50 #define HV_ICTIMESYNCFLAG_SAMPLE    2
  51 #define HV_NANO_SEC_PER_SEC         1000000000
  52
  53 /* Time Sync data */
  54 typedef struct {
  55         uint64_t data;
  56 } time_sync_data;
  57
  58         /* Time Synch Service */
  59 static const struct hyperv_guid service_guid = {.hv_guid =
  60         {0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
  61         0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf } };
  62
  63 struct hv_ictimesync_data {
  64         uint64_t    parenttime;
  65         uint64_t    childtime;
  66         uint64_t    roundtriptime;
  67         uint8_t     flags;
  68 } __packed;
  69
  70 typedef struct hv_timesync_sc {
  71         hv_util_sc      util_sc;
  72         struct task     task;
  73         time_sync_data  time_msg;
  74 } hv_timesync_sc;
  75
  76 /**
  77  * Set host time based on time sync message from host
  78  */
  79 static void
  80 hv_set_host_time(void *context, int pending)
  81 {
  82         hv_timesync_sc *softc = (hv_timesync_sc*)context;
  83         uint64_t hosttime = softc->time_msg.data;
  84         struct timespec guest_ts, host_ts;
  85         uint64_t host_tns;
  86         int64_t diff;
  87         int error;
  88
  89         host_tns = (hosttime - HV_WLTIMEDELTA) * 100;
  90         host_ts.tv_sec = (time_t)(host_tns/HV_NANO_SEC_PER_SEC);
  91         host_ts.tv_nsec = (long)(host_tns%HV_NANO_SEC_PER_SEC);
  92
  93         nanotime(&guest_ts);
  94
  95         diff = (int64_t)host_ts.tv_sec - (int64_t)guest_ts.tv_sec;
  96
  97         /*
  98          * If host differs by 5 seconds then make the guest catch up
  99          */
 100         if (diff > 5 || diff < -5) {
 101                 error = kern_clock_settime(curthread, CLOCK_REALTIME,
 102                     &host_ts);
 103         }
 104 }
 105
 106 /**
 107  * @brief Synchronize time with host after reboot, restore, etc.
 108  *
 109  * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM.
 110  * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time
 111  * message after the timesync channel is opened. Since the hv_utils module is
 112  * loaded after hv_vmbus, the first message is usually missed. The other
 113  * thing is, systime is automatically set to emulated hardware clock which may
 114  * not be UTC time or in the same time zone. So, to override these effects, we
 115  * use the first 50 time samples for initial system time setting.
 116  */
 117 static inline
 118 void hv_adj_guesttime(hv_timesync_sc *sc, uint64_t hosttime, uint8_t flags)
 119 {
 120         sc->time_msg.data = hosttime;
 121
 122         if (((flags & HV_ICTIMESYNCFLAG_SYNC) != 0) ||
 123                 ((flags & HV_ICTIMESYNCFLAG_SAMPLE) != 0)) {
 124                 taskqueue_enqueue(taskqueue_thread, &sc->task);
 125         }
 126 }
 127
 128 /**
 129  * Time Sync Channel message handler
 130  */
 131 static void
 132 hv_timesync_cb(void *context)
 133 {
 134         hv_vmbus_channel*       channel;
 135         hv_vmbus_icmsg_hdr*     icmsghdrp;
 136         uint32_t                recvlen;
 137         uint64_t                requestId;
 138         int                     ret;
 139         uint8_t*                time_buf;
 140         struct hv_ictimesync_data* timedatap;
 141         hv_timesync_sc          *softc;
 142
 143         softc = (hv_timesync_sc*)context;
 144         channel = softc->util_sc.channel;
 145         time_buf = softc->util_sc.receive_buffer;
 146
 147         ret = hv_vmbus_channel_recv_packet(channel, time_buf,
 148                 PAGE_SIZE, &recvlen, &requestId);
 149
 150         if ((ret == 0) && recvlen > 0) {
 151             icmsghdrp = (struct hv_vmbus_icmsg_hdr *) &time_buf[
 152                 sizeof(struct hv_vmbus_pipe_hdr)];
 153
 154             if (icmsghdrp->icmsgtype == HV_ICMSGTYPE_NEGOTIATE) {
 155                 hv_negotiate_version(icmsghdrp, NULL, time_buf);
 156             } else {
 157                 timedatap = (struct hv_ictimesync_data *) &time_buf[
 158                     sizeof(struct hv_vmbus_pipe_hdr) +
 159                         sizeof(struct hv_vmbus_icmsg_hdr)];
 160                 hv_adj_guesttime(softc, timedatap->parenttime, timedatap->flags);
 161             }
 162
 163             icmsghdrp->icflags = HV_ICMSGHDRFLAG_TRANSACTION
 164                 | HV_ICMSGHDRFLAG_RESPONSE;
 165
 166             vmbus_chan_send(channel, VMBUS_CHANPKT_TYPE_INBAND, 0,
 167                 time_buf, recvlen, requestId);
 168         }
 169 }
 170
 171 static int
 172 hv_timesync_probe(device_t dev)
 173 {
 174         if (resource_disabled("hvtimesync", 0))
 175                 return ENXIO;
 176
 177         if (VMBUS_PROBE_GUID(device_get_parent(dev), dev, &service_guid) == 0) {
 178                 device_set_desc(dev, "Hyper-V Time Synch Service");
 179                 return BUS_PROBE_DEFAULT;
 180         }
 181         return ENXIO;
 182 }
 183
 184 static int
 185 hv_timesync_attach(device_t dev)
 186 {
 187         hv_timesync_sc *softc = device_get_softc(dev);
 188
 189         softc->util_sc.callback = hv_timesync_cb;
 190         TASK_INIT(&softc->task, 1, hv_set_host_time, softc);
 191
 192         return hv_util_attach(dev);
 193 }
 194
 195 static int
 196 hv_timesync_detach(device_t dev)
 197 {
 198         hv_timesync_sc *softc = device_get_softc(dev);
 199         taskqueue_drain(taskqueue_thread, &softc->task);
 200
 201         return hv_util_detach(dev);
 202 }
 203
 204 static device_method_t timesync_methods[] = {
 205         /* Device interface */
 206         DEVMETHOD(device_probe, hv_timesync_probe),
 207         DEVMETHOD(device_attach, hv_timesync_attach),
 208         DEVMETHOD(device_detach, hv_timesync_detach),
 209         { 0, 0 }
 210 };
 211
 212 static driver_t timesync_driver = { "hvtimesync", timesync_methods, sizeof(hv_timesync_sc)};
 213
 214 static devclass_t timesync_devclass;
 215
 216 DRIVER_MODULE(hv_timesync, vmbus, timesync_driver, timesync_devclass, NULL, NULL);
 217 MODULE_VERSION(hv_timesync, 1);
 218 MODULE_DEPEND(hv_timesync, vmbus, 1, 1, 1);