pmtmr.c revision 245899 
1/*-
2 * Copyright (c) 2012 NetApp, Inc.
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, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY NETAPP, INC ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL NETAPP, INC OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/usr.sbin/bhyve/pmtmr.c 245899 2013-01-25 06:27:03Z neel $
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/usr.sbin/bhyve/pmtmr.c 245899 2013-01-25 06:27:03Z neel $");
31
32#include <sys/types.h>
33#include <sys/sysctl.h>
34#include <sys/time.h>
35#include <machine/cpufunc.h>
36
37#include <stdio.h>
38#include <time.h>
39#include <assert.h>
40#include <pthread.h>
41
42#include "inout.h"
43
44/*
45 * The ACPI Power Management timer is a free-running 24- or 32-bit
46 * timer with a frequency of 3.579545MHz
47 *
48 * This implementation will be 32-bits
49 */
50
51#define	IO_PMTMR	0x408	/* 4-byte i/o port for the timer */
52
53#define PMTMR_FREQ	3579545  /* 3.579545MHz */
54
55static pthread_mutex_t pmtmr_mtx;
56static uint64_t	pmtmr_tscf;
57static uint64_t	pmtmr_old;
58static uint64_t	pmtmr_tsc_old;
59
60static uint32_t
61pmtmr_val(void)
62{
63	uint64_t	pmtmr_tsc_new;
64	uint64_t	pmtmr_new;
65	static int	inited = 0;
66
67	if (!inited) {
68		size_t len;
69
70		inited = 1;
71		pthread_mutex_init(&pmtmr_mtx, NULL);
72		len = sizeof(pmtmr_tscf);
73		sysctlbyname("machdep.tsc_freq", &pmtmr_tscf, &len,
74		    NULL, 0);
75		pmtmr_tsc_old = rdtsc();
76		pmtmr_old = pmtmr_tsc_old / pmtmr_tscf * PMTMR_FREQ;
77	}
78
79	pthread_mutex_lock(&pmtmr_mtx);
80	pmtmr_tsc_new = rdtsc();
81	pmtmr_new = (pmtmr_tsc_new - pmtmr_tsc_old) * PMTMR_FREQ / pmtmr_tscf +
82	    pmtmr_old;
83	pmtmr_old = pmtmr_new;
84	pmtmr_tsc_old = pmtmr_tsc_new;
85	pthread_mutex_unlock(&pmtmr_mtx);
86
87	return (pmtmr_new);
88}
89
90static int
91pmtmr_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
92	          uint32_t *eax, void *arg)
93{
94	assert(in == 1);
95
96	if (bytes != 4)
97		return (-1);
98
99	*eax = pmtmr_val();
100
101	return (0);
102}
103
104INOUT_PORT(pmtmr, IO_PMTMR, IOPORT_F_IN, pmtmr_handler);
105
106