xref: /freebsd/sys/amd64/vmm/io/vpmtmr.c (revision 3c4ba5f55438f7afd4f4b0b56f88f2bb505fd6a6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2014, Neel Natu (neel@freebsd.org)
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice unmodified, this list of conditions, and the following
12  *    disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_bhyve_snapshot.h"
33 
34 #include <sys/param.h>
35 #include <sys/queue.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/systm.h>
39 
40 #include <machine/vmm.h>
41 #include <machine/vmm_snapshot.h>
42 
43 #include "vpmtmr.h"
44 
45 /*
46  * The ACPI Power Management timer is a free-running 24- or 32-bit
47  * timer with a frequency of 3.579545MHz
48  *
49  * This implementation will be 32-bits
50  */
51 
52 #define PMTMR_FREQ	3579545  /* 3.579545MHz */
53 
54 struct vpmtmr {
55 	sbintime_t	freq_sbt;
56 	sbintime_t	baseuptime;
57 	uint32_t	baseval;
58 };
59 
60 static MALLOC_DEFINE(M_VPMTMR, "vpmtmr", "bhyve virtual acpi timer");
61 
62 struct vpmtmr *
63 vpmtmr_init(struct vm *vm)
64 {
65 	struct vpmtmr *vpmtmr;
66 	struct bintime bt;
67 
68 	vpmtmr = malloc(sizeof(struct vpmtmr), M_VPMTMR, M_WAITOK | M_ZERO);
69 	vpmtmr->baseuptime = sbinuptime();
70 	vpmtmr->baseval = 0;
71 
72 	FREQ2BT(PMTMR_FREQ, &bt);
73 	vpmtmr->freq_sbt = bttosbt(bt);
74 
75 	return (vpmtmr);
76 }
77 
78 void
79 vpmtmr_cleanup(struct vpmtmr *vpmtmr)
80 {
81 
82 	free(vpmtmr, M_VPMTMR);
83 }
84 
85 int
86 vpmtmr_handler(struct vm *vm, bool in, int port, int bytes, uint32_t *val)
87 {
88 	struct vpmtmr *vpmtmr;
89 	sbintime_t now, delta;
90 
91 	if (!in || bytes != 4)
92 		return (-1);
93 
94 	vpmtmr = vm_pmtmr(vm);
95 
96 	/*
97 	 * No locking needed because 'baseuptime' and 'baseval' are
98 	 * written only during initialization.
99 	 */
100 	now = sbinuptime();
101 	delta = now - vpmtmr->baseuptime;
102 	KASSERT(delta >= 0, ("vpmtmr_handler: uptime went backwards: "
103 	    "%#lx to %#lx", vpmtmr->baseuptime, now));
104 	*val = vpmtmr->baseval + delta / vpmtmr->freq_sbt;
105 
106 	return (0);
107 }
108 
109 #ifdef BHYVE_SNAPSHOT
110 int
111 vpmtmr_snapshot(struct vpmtmr *vpmtmr, struct vm_snapshot_meta *meta)
112 {
113 	int ret;
114 
115 	SNAPSHOT_VAR_OR_LEAVE(vpmtmr->baseval, meta, ret, done);
116 
117 done:
118 	return (ret);
119 }
120 #endif
121