xref: /freebsd/sys/dev/hyperv/utilities/vmbus_timesync.c (revision 69b12e53db63e57d51e48486eaa5c24c31ff6fb1)
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 #define VMBUS_TIMESYNC_FWVER_MAJOR	3
44 #define VMBUS_TIMESYNC_FWVER		\
45 	VMBUS_IC_VERSION(VMBUS_TIMESYNC_FWVER_MAJOR, 0)
46 
47 #define VMBUS_TIMESYNC_MSGVER_MAJOR	4
48 #define VMBUS_TIMESYNC_MSGVER		\
49 	VMBUS_IC_VERSION(VMBUS_TIMESYNC_MSGVER_MAJOR, 0)
50 
51 #define VMBUS_TIMESYNC_MSGVER4(sc)	\
52 	VMBUS_ICVER_LE(VMBUS_IC_VERSION(4, 0), (sc)->ic_msgver)
53 
54 #define VMBUS_TIMESYNC_DORTT(sc)	\
55 	(VMBUS_TIMESYNC_MSGVER4((sc)) &&\
56 	 (hyperv_features & CPUID_HV_MSR_TIME_REFCNT))
57 
58 static int			vmbus_timesync_probe(device_t);
59 static int			vmbus_timesync_attach(device_t);
60 
61 static const struct vmbus_ic_desc vmbus_timesync_descs[] = {
62 	{
63 		.ic_guid = { .hv_guid = {
64 		    0x30, 0xe6, 0x27, 0x95, 0xae, 0xd0, 0x7b, 0x49,
65 		    0xad, 0xce, 0xe8, 0x0a, 0xb0, 0x17, 0x5c, 0xaf } },
66 		.ic_desc = "Hyper-V Timesync"
67 	},
68 	VMBUS_IC_DESC_END
69 };
70 
71 static device_method_t vmbus_timesync_methods[] = {
72 	/* Device interface */
73 	DEVMETHOD(device_probe,		vmbus_timesync_probe),
74 	DEVMETHOD(device_attach,	vmbus_timesync_attach),
75 	DEVMETHOD(device_detach,	vmbus_ic_detach),
76 	DEVMETHOD_END
77 };
78 
79 static driver_t vmbus_timesync_driver = {
80 	"hvtimesync",
81 	vmbus_timesync_methods,
82 	sizeof(struct vmbus_ic_softc)
83 };
84 
85 static devclass_t vmbus_timesync_devclass;
86 
87 DRIVER_MODULE(hv_timesync, vmbus, vmbus_timesync_driver,
88     vmbus_timesync_devclass, NULL, NULL);
89 MODULE_VERSION(hv_timesync, 1);
90 MODULE_DEPEND(hv_timesync, vmbus, 1, 1, 1);
91 
92 SYSCTL_NODE(_hw, OID_AUTO, hvtimesync, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL,
93     "Hyper-V timesync interface");
94 
95 static int vmbus_ts_ignore_sync = 0;
96 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, ignore_sync, CTLFLAG_RWTUN,
97     &vmbus_ts_ignore_sync, 0, "Ignore the sync request.");
98 
99 /*
100  * Trigger sample sync when drift exceeds threshold (ms).
101  * Ignore the sample request when set to 0.
102  */
103 static int vmbus_ts_sample_thresh = 100;
104 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, sample_thresh, CTLFLAG_RWTUN,
105     &vmbus_ts_sample_thresh, 0,
106     "Threshold that makes sample request trigger the sync (unit: ms).");
107 
108 static int vmbus_ts_sample_verbose = 0;
109 SYSCTL_INT(_hw_hvtimesync, OID_AUTO, sample_verbose, CTLFLAG_RWTUN,
110     &vmbus_ts_sample_verbose, 0, "Increase sample request verbosity.");
111 
112 static void
113 vmbus_timesync(struct vmbus_ic_softc *sc, uint64_t hvtime, uint64_t sent_tc,
114     uint8_t tsflags)
115 {
116 	struct timespec vm_ts;
117 	uint64_t hv_ns, vm_ns, rtt = 0;
118 
119 	if (VMBUS_TIMESYNC_DORTT(sc))
120 		rtt = rdmsr(MSR_HV_TIME_REF_COUNT) - sent_tc;
121 
122 	hv_ns = (hvtime - VMBUS_ICMSG_TS_BASE + rtt) * HYPERV_TIMER_NS_FACTOR;
123 	nanotime(&vm_ts);
124 	vm_ns = (vm_ts.tv_sec * NANOSEC) + vm_ts.tv_nsec;
125 
126 	if ((tsflags & VMBUS_ICMSG_TS_FLAG_SYNC) && !vmbus_ts_ignore_sync) {
127 		struct timespec hv_ts;
128 
129 		if (bootverbose) {
130 			device_printf(sc->ic_dev, "apply sync request, "
131 			    "hv: %ju, vm: %ju\n",
132 			    (uintmax_t)hv_ns, (uintmax_t)vm_ns);
133 		}
134 		hv_ts.tv_sec = hv_ns / NANOSEC;
135 		hv_ts.tv_nsec = hv_ns % NANOSEC;
136 		kern_clock_settime(curthread, CLOCK_REALTIME, &hv_ts);
137 		/* Done! */
138 		return;
139 	}
140 
141 	if ((tsflags & VMBUS_ICMSG_TS_FLAG_SAMPLE) &&
142 	    vmbus_ts_sample_thresh > 0) {
143 		int64_t diff;
144 
145 		if (vmbus_ts_sample_verbose) {
146 			device_printf(sc->ic_dev, "sample request, "
147 			    "hv: %ju, vm: %ju\n",
148 			    (uintmax_t)hv_ns, (uintmax_t)vm_ns);
149 		}
150 
151 		if (hv_ns > vm_ns)
152 			diff = hv_ns - vm_ns;
153 		else
154 			diff = vm_ns - hv_ns;
155 		/* nanosec -> millisec */
156 		diff /= 1000000;
157 
158 		if (diff > vmbus_ts_sample_thresh) {
159 			struct timespec hv_ts;
160 
161 			if (bootverbose) {
162 				device_printf(sc->ic_dev,
163 				    "apply sample request, hv: %ju, vm: %ju\n",
164 				    (uintmax_t)hv_ns, (uintmax_t)vm_ns);
165 			}
166 			hv_ts.tv_sec = hv_ns / NANOSEC;
167 			hv_ts.tv_nsec = hv_ns % NANOSEC;
168 			kern_clock_settime(curthread, CLOCK_REALTIME, &hv_ts);
169 		}
170 		/* Done */
171 		return;
172 	}
173 }
174 
175 static void
176 vmbus_timesync_cb(struct vmbus_channel *chan, void *xsc)
177 {
178 	struct vmbus_ic_softc *sc = xsc;
179 	struct vmbus_icmsg_hdr *hdr;
180 	int dlen, error;
181 	uint64_t xactid;
182 	void *data;
183 
184 	/*
185 	 * Receive request.
186 	 */
187 	data = sc->ic_buf;
188 	dlen = sc->ic_buflen;
189 	error = vmbus_chan_recv(chan, data, &dlen, &xactid);
190 	KASSERT(error != ENOBUFS, ("icbuf is not large enough"));
191 	if (error)
192 		return;
193 
194 	if (dlen < sizeof(*hdr)) {
195 		device_printf(sc->ic_dev, "invalid data len %d\n", dlen);
196 		return;
197 	}
198 	hdr = data;
199 
200 	/*
201 	 * Update request, which will be echoed back as response.
202 	 */
203 	switch (hdr->ic_type) {
204 	case VMBUS_ICMSG_TYPE_NEGOTIATE:
205 		error = vmbus_ic_negomsg(sc, data, &dlen,
206 		    VMBUS_TIMESYNC_FWVER, VMBUS_TIMESYNC_MSGVER);
207 		if (error)
208 			return;
209 		if (VMBUS_TIMESYNC_DORTT(sc))
210 			device_printf(sc->ic_dev, "RTT\n");
211 		break;
212 
213 	case VMBUS_ICMSG_TYPE_TIMESYNC:
214 		if (VMBUS_TIMESYNC_MSGVER4(sc)) {
215 			const struct vmbus_icmsg_timesync4 *msg4;
216 
217 			if (dlen < sizeof(*msg4)) {
218 				device_printf(sc->ic_dev, "invalid timesync4 "
219 				    "len %d\n", dlen);
220 				return;
221 			}
222 			msg4 = data;
223 			vmbus_timesync(sc, msg4->ic_hvtime, msg4->ic_sent_tc,
224 			    msg4->ic_tsflags);
225 		} else {
226 			const struct vmbus_icmsg_timesync *msg;
227 
228 			if (dlen < sizeof(*msg)) {
229 				device_printf(sc->ic_dev, "invalid timesync "
230 				    "len %d\n", dlen);
231 				return;
232 			}
233 			msg = data;
234 			vmbus_timesync(sc, msg->ic_hvtime, 0, msg->ic_tsflags);
235 		}
236 		break;
237 
238 	default:
239 		device_printf(sc->ic_dev, "got 0x%08x icmsg\n", hdr->ic_type);
240 		break;
241 	}
242 
243 	/*
244 	 * Send response by echoing the request back.
245 	 */
246 	vmbus_ic_sendresp(sc, chan, data, dlen, xactid);
247 }
248 
249 static int
250 vmbus_timesync_probe(device_t dev)
251 {
252 
253 	return (vmbus_ic_probe(dev, vmbus_timesync_descs));
254 }
255 
256 static int
257 vmbus_timesync_attach(device_t dev)
258 {
259 
260 	return (vmbus_ic_attach(dev, vmbus_timesync_cb));
261 }
262