blob: 5509a742ce53893739c834f113bc4e77af4530b3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2021 Jason King
*/
#include <sys/x86_archext.h>
#include <sys/tsc.h>
/* For VMs, this leaf will contain the largest VM leaf supported in EAX */
#define CPUID_VM_LEAF_MAX 0x40000000
/*
* From https://lwn.net/Articles/301888/, CPUID leaf 0x40000010 (when present)
* on VMware will contain the TSC frequency in kHz. While it would have been
* nice to locate an official bit of documentation from VMware, implementations
* in both Linux and FreeBSD agree with the above link, so it seems reasonable
* to use it as well.
*/
#define CPUID_VM_LEAF_FREQ 0x40000010
static boolean_t
tsc_calibrate_vmware(uint64_t *freqp)
{
if (get_hwenv() != HW_VMWARE)
return (B_FALSE);
struct cpuid_regs regs = { 0 };
/* First determine the largest VM leaf supported */
regs.cp_eax = CPUID_VM_LEAF_MAX;
__cpuid_insn(®s);
if (regs.cp_eax < CPUID_VM_LEAF_FREQ)
return (B_FALSE);
regs.cp_eax = CPUID_VM_LEAF_FREQ;
__cpuid_insn(®s);
/*
* While not observed in the wild, as a precautionary measure,
* we treat a value of 0 as a failure out of an excess of caution.
*/
if (regs.cp_eax == 0)
return (B_FALSE);
/* Convert from kHz to Hz */
*freqp = (uint64_t)regs.cp_eax * 1000;
return (B_TRUE);
}
static tsc_calibrate_t tsc_calibration_vmware = {
.tscc_source = "VMware",
.tscc_preference = 100,
.tscc_calibrate = tsc_calibrate_vmware,
};
TSC_CALIBRATION_SOURCE(tsc_calibration_vmware);
|
