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
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/bus.h>
  32 #include <sys/kernel.h>
  33 #include <sys/module.h>
  34 #include <sys/syscallsubr.h>
  35 #include <sys/sysctl.h>
  36 #include <sys/systm.h>
  37
  38 #include <dev/hyperv/include/hyperv.h>
  39 #include <dev/hyperv/include/vmbus.h>
  40 #include <dev/hyperv/utilities/vmbus_icreg.h>
  41 #include <dev/hyperv/utilities/vmbus_icvar.h>
  42
  43 #include "vmbus_if.h"
  44
  45 #define VMBUS_TIMESYNC_FWVER_MAJOR      3
  46 #define VMBUS_TIMESYNC_FWVER            \
  47         VMBUS_IC_VERSION(VMBUS_TIMESYNC_FWVER_MAJOR, 0)
  48
  49 #define VMBUS_TIMESYNC_MSGVER_MAJOR     4
  50 #define VMBUS_TIMESYNC_MSGVER           \
  51         VMBUS_IC_VERSION(VMBUS_TIMESYNC_MSGVER_MAJOR, 0)
  52
  53 #define VMBUS_TIMESYNC_DORTT(sc)        \
  54         ((sc)->ic_msgver >= VMBUS_IC_VERSION(4, 0) && \
  55          (hyperv_features & CPUID_HV_MSR_TIME_REFCNT))
  56
  57 static const struct vmbus_ic_desc vmbus_timesync_descs[] = {
  58         {
  59                 .ic_guid = { .hv_guid = {
  60                     0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
  61                     0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf } },
  62                 .ic_desc = "Hyper-V Timesync"
  63         },
  64         VMBUS_IC_DESC_END
  65 };
  66
  67 SYSCTL_NODE(_hw, OID_AUTO, hvtimesync, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
  68     "Hyper-V timesync interface");
  69
  70 static int vmbus_ts_ignore_sync = 0;
  71 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, ignore_sync, CTLFLAG_RWTUN,
  72     &vmbus_ts_ignore_sync, 0, "Ignore the sync request.");
  73
  74 /*
  75  * Trigger sample sync when drift exceeds threshold (ms).
  76  * Ignore the sample request when set to 0.
  77  */
  78 static int vmbus_ts_sample_thresh = 100;
  79 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, sample_thresh, CTLFLAG_RWTUN,
  80     &vmbus_ts_sample_thresh, 0,
  81     "Threshold that makes sample request trigger the sync (unit: ms).");
  82
  83 static int vmbus_ts_sample_verbose = 0;
  84 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, sample_verbose, CTLFLAG_RWTUN,
  85     &vmbus_ts_sample_verbose, 0, "Increase sample request verbosity.");
  86
  87 static void
  88 vmbus_timesync(struct vmbus_ic_softc *sc, uint64_t hvtime, uint64_t sent_tc,
  89     uint8_t tsflags)
  90 {
  91         struct timespec vm_ts;
  92         uint64_t hv_ns, vm_ns, rtt = 0;
  93
  94         if (VMBUS_TIMESYNC_DORTT(sc))
  95                 rtt = rdmsr(MSR_HV_TIME_REF_COUNT) - sent_tc;
  96
  97         hv_ns = (hvtime - VMBUS_ICMSG_TS_BASE + rtt) * HYPERV_TIMER_NS_FACTOR;
  98         nanotime(&vm_ts);
  99         vm_ns = (vm_ts.tv_sec * NANOSEC) + vm_ts.tv_nsec;
 100
 101         if ((tsflags & VMBUS_ICMSG_TS_FLAG_SYNC) && !vmbus_ts_ignore_sync) {
 102                 struct timespec hv_ts;
 103
 104                 if (bootverbose) {
 105                         device_printf(sc->ic_dev, "apply sync request, "
 106                             "hv: %ju, vm: %ju\n",
 107                             (uintmax_t)hv_ns, (uintmax_t)vm_ns);
 108                 }
 109                 hv_ts.tv_sec = hv_ns / NANOSEC;
 110                 hv_ts.tv_nsec = hv_ns % NANOSEC;
 111                 kern_clock_settime(curthread, CLOCK_REALTIME, &hv_ts);
 112                 /* Done! */
 113                 return;
 114         }
 115
 116         if ((tsflags & VMBUS_ICMSG_TS_FLAG_SAMPLE) &&
 117             vmbus_ts_sample_thresh > 0) {
 118                 int64_t diff;
 119
 120                 if (vmbus_ts_sample_verbose) {
 121                         device_printf(sc->ic_dev, "sample request, "
 122                             "hv: %ju, vm: %ju\n",
 123                             (uintmax_t)hv_ns, (uintmax_t)vm_ns);
 124                 }
 125
 126                 if (hv_ns > vm_ns)
 127                         diff = hv_ns - vm_ns;
 128                 else
 129                         diff = vm_ns - hv_ns;
 130                 /* nanosec -> millisec */
 131                 diff /= 1000000;
 132
 133                 if (diff > vmbus_ts_sample_thresh) {
 134                         struct timespec hv_ts;
 135
 136                         if (bootverbose) {
 137                                 device_printf(sc->ic_dev,
 138                                     "apply sample request, hv: %ju, vm: %ju\n",
 139                                     (uintmax_t)hv_ns, (uintmax_t)vm_ns);
 140                         }
 141                         hv_ts.tv_sec = hv_ns / NANOSEC;
 142                         hv_ts.tv_nsec = hv_ns % NANOSEC;
 143                         kern_clock_settime(curthread, CLOCK_REALTIME, &hv_ts);
 144                 }
 145                 /* Done */
 146                 return;
 147         }
 148 }
 149
 150 static void
 151 vmbus_timesync_cb(struct vmbus_channel *chan, void *xsc)
 152 {
 153         struct vmbus_ic_softc *sc = xsc;
 154         struct vmbus_icmsg_hdr *hdr;
 155         const struct vmbus_icmsg_timesync *msg;
 156         int dlen, error;
 157         uint64_t xactid;
 158         void *data;
 159
 160         /*
 161          * Receive request.
 162          */
 163         data = sc->ic_buf;
 164         dlen = sc->ic_buflen;
 165         error = vmbus_chan_recv(chan, data, &dlen, &xactid);
 166         KASSERT(error != ENOBUFS, ("icbuf is not large enough"));
 167         if (error)
 168                 return;
 169
 170         if (dlen < sizeof(*hdr)) {
 171                 device_printf(sc->ic_dev, "invalid data len %d\n", dlen);
 172                 return;
 173         }
 174         hdr = data;
 175
 176         /*
 177          * Update request, which will be echoed back as response.
 178          */
 179         switch (hdr->ic_type) {
 180         case VMBUS_ICMSG_TYPE_NEGOTIATE:
 181                 error = vmbus_ic_negomsg(sc, data, &dlen,
 182                     VMBUS_TIMESYNC_FWVER, VMBUS_TIMESYNC_MSGVER);
 183                 if (error)
 184                         return;
 185                 if (VMBUS_TIMESYNC_DORTT(sc))
 186                         device_printf(sc->ic_dev, "RTT\n");
 187                 break;
 188
 189         case VMBUS_ICMSG_TYPE_TIMESYNC:
 190                 if (dlen < sizeof(*msg)) {
 191                         device_printf(sc->ic_dev, "invalid timesync len %d\n",
 192                             dlen);
 193                         return;
 194                 }
 195                 msg = data;
 196                 vmbus_timesync(sc, msg->ic_hvtime, msg->ic_sent_tc,
 197                     msg->ic_tsflags);
 198                 break;
 199
 200         default:
 201                 device_printf(sc->ic_dev, "got 0x%08x icmsg\n", hdr->ic_type);
 202                 break;
 203         }
 204
 205         /*
 206          * Send response by echoing the request back.
 207          */
 208         vmbus_ic_sendresp(sc, chan, data, dlen, xactid);
 209 }
 210
 211 static int
 212 hv_timesync_probe(device_t dev)
 213 {
 214
 215         return (vmbus_ic_probe(dev, vmbus_timesync_descs));
 216 }
 217
 218 static int
 219 hv_timesync_attach(device_t dev)
 220 {
 221
 222         return (vmbus_ic_attach(dev, vmbus_timesync_cb));
 223 }
 224
 225 static device_method_t timesync_methods[] = {
 226         /* Device interface */
 227         DEVMETHOD(device_probe, hv_timesync_probe),
 228         DEVMETHOD(device_attach, hv_timesync_attach),
 229         DEVMETHOD(device_detach, vmbus_ic_detach),
 230         { 0, 0 }
 231 };
 232
 233 static driver_t timesync_driver = {
 234         "hvtimesync",
 235         timesync_methods,
 236         sizeof(struct vmbus_ic_softc)
 237 };
 238
 239 static devclass_t timesync_devclass;
 240
 241 DRIVER_MODULE(hv_timesync, vmbus, timesync_driver, timesync_devclass, NULL, NULL);
 242 MODULE_VERSION(hv_timesync, 1);
 243 MODULE_DEPEND(hv_timesync, vmbus, 1, 1, 1);