VirtualBox

source: vbox/trunk/src/VBox/VMM/tools/VBoxCpuReportMsrLinux.cpp@ 104116

Last change on this file since 104116 was 98103, checked in by vboxsync, 2 years ago

Copyright year updates by scm.

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1/* $Id: VBoxCpuReportMsrLinux.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
2/** @file
3 * MsrLinux - Linux-specific MSR access.
4 */
5
6/*
7 * Copyright (C) 2013-2023 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * SPDX-License-Identifier: GPL-3.0-only
26 */
27
28
29/*********************************************************************************************************************************
30* Header Files *
31*********************************************************************************************************************************/
32#include "VBoxCpuReport.h"
33
34#include <iprt/err.h>
35#include <iprt/file.h>
36#include <iprt/thread.h>
37
38#ifndef RT_OS_WINDOWS
39# include <unistd.h>
40#else /* RT_OS_WINDOWS: for test compiling this file on windows */
41# include <io.h>
42int pread(int, void *, size_t, off_t);
43int pwrite(int, void const *, size_t, off_t);
44#endif
45#include <fcntl.h>
46#include <errno.h>
47
48
49/*********************************************************************************************************************************
50* Defined Constants And Macros *
51*********************************************************************************************************************************/
52#define MSR_DEV_NAME "/dev/cpu/0/msr"
53
54
55/*********************************************************************************************************************************
56* Global Variables *
57*********************************************************************************************************************************/
58/** The /dev/xxx/msr file descriptor. */
59static int g_fdMsr;
60
61
62/**
63 * @interface_method_impl{VBCPUREPMSRACCESSORS,pfnMsrProberRead}
64 */
65static DECLCALLBACK(int) linuxMsrProberRead(uint32_t uMsr, RTCPUID idCpu, uint64_t *puValue, bool *pfGp)
66{
67 int rc = VINF_SUCCESS;
68
69 if (idCpu != NIL_RTCPUID)
70 return VERR_INVALID_PARAMETER;
71
72 if (g_fdMsr < 0)
73 return VERR_INVALID_STATE;
74
75 *pfGp = true;
76 if (pread(g_fdMsr, puValue, sizeof(*puValue), uMsr) != sizeof(*puValue))
77 rc = VERR_READ_ERROR;
78 else
79 *pfGp = false;
80
81 return RT_SUCCESS(rc) && !pfGp;
82}
83
84
85/**
86 * @interface_method_impl{VBCPUREPMSRACCESSORS,pfnMsrProberWrite}
87 */
88static DECLCALLBACK(int) linuxMsrProberWrite(uint32_t uMsr, RTCPUID idCpu, uint64_t uValue, bool *pfGp)
89{
90 int rc = VINF_SUCCESS;
91
92 if (idCpu != NIL_RTCPUID)
93 return VERR_INVALID_PARAMETER;
94
95 if (g_fdMsr < 0)
96 return VERR_INVALID_STATE;
97
98 *pfGp = true;
99 if (pwrite(g_fdMsr, &uValue, sizeof(uValue), uMsr) != sizeof(uValue))
100 rc = VERR_WRITE_ERROR;
101 else
102 *pfGp = false;
103
104 return RT_SUCCESS(rc) && !pfGp;
105}
106
107/**
108 * @interface_method_impl{VBCPUREPMSRACCESSORS,pfnMsrProberModify}
109 */
110static DECLCALLBACK(int) linuxMsrProberModify(uint32_t uMsr, RTCPUID idCpu, uint64_t fAndMask, uint64_t fOrMask,
111 PSUPMSRPROBERMODIFYRESULT pResult)
112{
113 int rc = VINF_SUCCESS;
114 uint64_t uBefore, uWrite, uAfter;
115 int rcBefore, rcWrite, rcAfter, rcRestore;
116
117 if (idCpu != NIL_RTCPUID)
118 return VERR_INVALID_PARAMETER;
119
120 if (g_fdMsr < 0)
121 return VERR_INVALID_STATE;
122
123#if 0
124 vbCpuRepDebug("MSR %#x\n", uMsr);
125 RTThreadSleep(10);
126#endif
127 rcBefore = pread(g_fdMsr, &uBefore, sizeof(uBefore), uMsr);
128 uWrite = (uBefore & fAndMask) | fOrMask;
129 rcWrite = pwrite(g_fdMsr, &uWrite, sizeof(uWrite), uMsr);
130 rcAfter = pread(g_fdMsr, &uAfter, sizeof(uAfter), uMsr);
131 rcRestore = pwrite(g_fdMsr, &uBefore, sizeof(uBefore), uMsr);
132
133#if 0
134 vbCpuRepDebug("MSR: %#x, %#llx -> %#llx -> %#llx (%d/%d/%d/%d)\n",
135 uMsr, uBefore, uWrite, uAfter,
136 rcBefore, rcWrite != sizeof(uWrite), rcAfter, rcRestore);
137#endif
138 pResult->uBefore = uBefore;
139 pResult->uWritten = uWrite;
140 pResult->uAfter = uAfter;
141 pResult->fBeforeGp = rcBefore != sizeof(uBefore);
142 pResult->fModifyGp = rcWrite != sizeof(uWrite);
143 pResult->fAfterGp = rcAfter != sizeof(uAfter);
144 pResult->fRestoreGp = rcRestore != sizeof(uBefore);
145
146 return rc;
147}
148
149
150/**
151 * @interface_method_impl{VBCPUREPMSRACCESSORS,pfnTerm}
152 */
153static DECLCALLBACK(void) linuxMsrProberTerm(void)
154{
155 if (g_fdMsr >= 0)
156 {
157 close(g_fdMsr);
158 g_fdMsr = -1;
159 }
160}
161
162int VbCpuRepMsrProberInitPlatform(PVBCPUREPMSRACCESSORS pMsrAccessors)
163{
164 RTFILE hFile;
165 int rc = RTFileOpen(&hFile, MSR_DEV_NAME, RTFILE_O_READWRITE | RTFILE_O_DENY_NONE | RTFILE_O_OPEN);
166 if (RT_SUCCESS(rc))
167 {
168 g_fdMsr = RTFileToNative(hFile);
169 Assert(g_fdMsr != -1);
170
171 pMsrAccessors->fAtomic = false; /* Can't modify/restore MSRs without trip to R3. */
172 pMsrAccessors->pfnMsrProberRead = linuxMsrProberRead;
173 pMsrAccessors->pfnMsrProberWrite = linuxMsrProberWrite;
174 pMsrAccessors->pfnMsrProberModify = linuxMsrProberModify;
175 pMsrAccessors->pfnTerm = linuxMsrProberTerm;
176 return VINF_SUCCESS;
177 }
178 vbCpuRepDebug("warning: Failed to open " MSR_DEV_NAME ": %Rrc\n", rc);
179 return rc;
180}
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