xref: /illumos-gate/usr/src/test/bhyve-tests/tests/kdev/payload_rdmsr_tsc.c (revision 1a2d662a91cee3bf82f41cd47c7ae6f3825d9db2)
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 2023 Oxide Computer Company
14  */
15 
16 #include "payload_common.h"
17 #include "payload_utils.h"
18 #include "test_defs.h"
19 
20 #define	UINT32_MAX	0xffffffff
21 #define	MSR_TSC	0x10
22 
23 void
24 start(void)
25 {
26 	/* write a value to the TSC */
27 	wrmsr(MSR_TSC, TSC_TARGET_WRVAL);
28 
29 	/* loop for as long as the host wants */
30 	for (;;) {
31 		uint64_t tsc = rdmsr(MSR_TSC);
32 		outl(IOP_TEST_VALUE, UINT32_MAX & tsc);
33 		outl(IOP_TEST_VALUE, UINT32_MAX & (tsc >> 32));
34 	}
35 }
36