xref: /illumos-gate/usr/src/test/bhyve-tests/tests/kdev/vatpit_freq.c (revision b93865c3d90e9b0d73e338c9abb3293c35c571a8)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2022 Oxide Computer Company
14  */
15 
16 #include <stdio.h>
17 #include <unistd.h>
18 #include <stdlib.h>
19 #include <strings.h>
20 #include <libgen.h>
21 #include <assert.h>
22 
23 #include <sys/types.h>
24 #include <sys/sysmacros.h>
25 #include <sys/debug.h>
26 #include <sys/vmm.h>
27 #include <sys/vmm_dev.h>
28 #include <vmmapi.h>
29 
30 #include "in_guest.h"
31 #include "test_defs.h"
32 
33 typedef struct reading {
34 	hrtime_t	when;
35 	uint16_t	value;
36 } reading_t;
37 
38 static bool
39 check_reading(reading_t before, reading_t after, uint_t tick_margin,
40     uint_t ppm_margin)
41 {
42 	hrtime_t time_delta = after.when - before.when;
43 	uint16_t tick_delta;
44 
45 	tick_delta = before.value - after.value;
46 
47 	/* is the number of ticks OK? */
48 	if (tick_delta < ATPIT_TARGET_TICKS) {
49 		test_fail_msg("inadequate passage of ticks %u < %u\n",
50 		    tick_delta, ATPIT_TARGET_TICKS);
51 	} else if ((tick_delta - ATPIT_TARGET_TICKS) > tick_margin) {
52 		(void) printf("%u ticks outside margin %u\n", tick_delta,
53 		    ATPIT_TARGET_TICKS + tick_margin);
54 		return (false);
55 	}
56 
57 	hrtime_t time_target = (tick_delta * NANOSEC) / ATPIT_FREQ;
58 
59 	hrtime_t offset;
60 	if (time_delta < time_target) {
61 		offset = time_target - time_delta;
62 	} else {
63 		offset = time_delta - time_target;
64 	}
65 	uint64_t ppm = (offset * 1000000) / time_target;
66 	(void) printf("margin limits: ticks=%u ppm=%lu\n",
67 	    tick_margin, ppm_margin);
68 	(void) printf("%u ticks in %lu ns (error %lu ppm)\n",
69 	    tick_delta, time_delta, ppm);
70 	if (ppm > ppm_margin) {
71 		(void) printf("UNACCEPTABLE!\n");
72 		return (false);
73 	}
74 	return (true);
75 }
76 
77 int
78 main(int argc, char *argv[])
79 {
80 	const char *test_suite_name = basename(argv[0]);
81 	struct vmctx *ctx = NULL;
82 	int err;
83 
84 	ctx = test_initialize(test_suite_name);
85 
86 	err = test_setup_vcpu(ctx, 0, MEM_LOC_PAYLOAD, MEM_LOC_STACK);
87 	if (err != 0) {
88 		test_fail_errno(err, "Could not initialize vcpu0");
89 	}
90 
91 	struct vm_entry ventry = { 0 };
92 	struct vm_exit vexit = { 0 };
93 	reading_t readings[2];
94 	uint_t nread = 0;
95 	uint_t nrepeat = 0;
96 
97 	/*
98 	 * Since the PIT is slower to read back (requiring 3 emulated reads),
99 	 * operate with a more loose ticks margin.
100 	 */
101 	const uint_t margin_ticks = MAX(1, ATPIT_TARGET_TICKS / 2500);
102 	const uint_t margin_ppm = 400;
103 
104 	do {
105 		const enum vm_exit_kind kind =
106 		    test_run_vcpu(ctx, 0, &ventry, &vexit);
107 		if (kind == VEK_REENTR) {
108 			continue;
109 		} else if (kind != VEK_UNHANDLED) {
110 			test_fail_vmexit(&vexit);
111 		}
112 
113 		uint32_t v;
114 		if (vexit_match_inout(&vexit, false, IOP_TEST_VALUE, 2, &v)) {
115 			readings[nread].when = gethrtime();
116 			readings[nread].value = v;
117 
118 			ventry_fulfill_inout(&vexit, &ventry, 0);
119 
120 			nread++;
121 			if (nread != 2) {
122 				continue;
123 			}
124 
125 			if (check_reading(readings[0], readings[1],
126 			    margin_ticks, margin_ppm)) {
127 				test_pass();
128 			} else {
129 				nrepeat++;
130 				if (nrepeat < 3) {
131 					nread = 0;
132 					(void) printf("retry %u\n", nrepeat);
133 					continue;
134 				}
135 				test_fail_msg("bad result after %u retries\n",
136 				    nrepeat);
137 			}
138 		} else {
139 			test_fail_vmexit(&vexit);
140 		}
141 
142 	} while (true);
143 
144 	return (0);
145 }
146