1 | /* $Id: PDMAllCritSect.cpp 8677 2008-05-07 18:13:32Z vboxsync $ */
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2 | /** @file
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3 | * PDM Critical Sections
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2006-2007 Sun Microsystems, Inc.
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8 | *
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9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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10 | * available from http://www.virtualbox.org. This file is free software;
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11 | * you can redistribute it and/or modify it under the terms of the GNU
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12 | * General Public License (GPL) as published by the Free Software
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13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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16 | *
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17 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
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18 | * Clara, CA 95054 USA or visit http://www.sun.com if you need
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19 | * additional information or have any questions.
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20 | */
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21 |
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22 |
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23 | /*******************************************************************************
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24 | * Header Files *
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25 | *******************************************************************************/
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26 | #define LOG_GROUP LOG_GROUP_PDM//_CRITSECT
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27 | #include "PDMInternal.h"
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28 | #include <VBox/pdm.h>
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29 | #include <VBox/mm.h>
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30 | #include <VBox/vm.h>
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31 | #include <VBox/err.h>
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32 |
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33 | #include <VBox/log.h>
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34 | #include <iprt/asm.h>
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35 | #include <iprt/assert.h>
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36 | #ifdef IN_RING3
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37 | # include <iprt/semaphore.h>
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38 | #endif
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39 |
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40 |
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41 | /**
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42 | * Enters a PDM critical section.
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43 | *
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44 | * @returns VINF_SUCCESS if entered successfully.
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45 | * @returns rcBusy when encountering a busy critical section in GC/R0.
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46 | * @returns VERR_SEM_DESTROYED if the critical section is dead.
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47 | *
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48 | * @param pCritSect The PDM critical section to enter.
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49 | * @param rcBusy The status code to return when we're in GC or R0
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50 | * and the section is busy.
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51 | */
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52 | PDMDECL(int) PDMCritSectEnter(PPDMCRITSECT pCritSect, int rcBusy)
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53 | {
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54 | Assert(pCritSect->s.Core.cNestings < 8); /* useful to catch incorrect locking */
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55 | #ifdef IN_RING3
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56 | NOREF(rcBusy);
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57 |
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58 | STAM_STATS({ if (pCritSect->s.Core.cLockers >= 0 && !RTCritSectIsOwner(&pCritSect->s.Core)) STAM_COUNTER_INC(&pCritSect->s.StatContentionR3); });
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59 | int rc = RTCritSectEnter(&pCritSect->s.Core);
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60 | STAM_STATS({ if (pCritSect->s.Core.cNestings == 1) STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l); });
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61 | return rc;
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62 |
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63 | #else
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64 | AssertMsgReturn(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC, ("%RX32\n", pCritSect->s.Core.u32Magic),
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65 | VERR_SEM_DESTROYED);
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66 | PVM pVM = pCritSect->s.CTXALLSUFF(pVM);
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67 | Assert(pVM);
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68 |
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69 | /*
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70 | * Try take the lock.
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71 | */
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72 | if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, 0, -1))
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73 | {
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74 | pCritSect->s.Core.cNestings = 1;
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75 | ASMAtomicXchgSize(&pCritSect->s.Core.NativeThreadOwner, pVM->NativeThreadEMT);
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76 | STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
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77 | return VINF_SUCCESS;
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78 | }
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79 |
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80 | /*
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81 | * Nested?
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82 | */
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83 | if (pCritSect->s.Core.NativeThreadOwner == pVM->NativeThreadEMT)
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84 | {
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85 | pCritSect->s.Core.cNestings++;
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86 | ASMAtomicIncS32(&pCritSect->s.Core.cLockers);
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87 | return VINF_SUCCESS;
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88 | }
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89 |
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90 | /*
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91 | * Failed.
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92 | */
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93 | LogFlow(("pcnetLock: locked => HC (%Vrc)\n", rcBusy));
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94 | STAM_COUNTER_INC(&pCritSect->s.StatContentionR0GCLock);
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95 | return rcBusy;
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96 | #endif
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97 | }
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98 |
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99 |
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100 | #ifdef IN_RING3
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101 | /**
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102 | * Enters a PDM critical section.
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103 | *
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104 | * @returns VINF_SUCCESS if entered successfully.
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105 | * @returns rcBusy when encountering a busy critical section in GC/R0.
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106 | * @returns VERR_SEM_DESTROYED if the critical section is dead.
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107 | *
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108 | * @param pCritSect The PDM critical section to enter.
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109 | * @param fCallHost Whether this is a VMMGCCallHost() or VMMR0CallHost() request.
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110 | */
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111 | PDMR3DECL(int) PDMR3CritSectEnterEx(PPDMCRITSECT pCritSect, bool fCallHost)
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112 | {
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113 | int rc = PDMCritSectEnter(pCritSect, VERR_INTERNAL_ERROR);
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114 | if ( rc == VINF_SUCCESS
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115 | && fCallHost
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116 | && pCritSect->s.Core.Strict.ThreadOwner != NIL_RTTHREAD)
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117 | {
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118 | RTThreadWriteLockDec(pCritSect->s.Core.Strict.ThreadOwner);
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119 | ASMAtomicUoWriteSize(&pCritSect->s.Core.Strict.ThreadOwner, NIL_RTTHREAD);
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120 | }
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121 | return rc;
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122 | }
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123 | #endif /* IN_RING3 */
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124 |
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125 |
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126 | /**
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127 | * Leaves a critical section entered with PDMCritSectEnter().
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128 | *
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129 | * @param pCritSect The PDM critical section to leave.
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130 | */
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131 | PDMDECL(void) PDMCritSectLeave(PPDMCRITSECT pCritSect)
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132 | {
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133 | #ifdef IN_RING3
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134 | # ifdef VBOX_WITH_STATISTICS
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135 | if (pCritSect->s.Core.cNestings == 1)
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136 | STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
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137 | # endif
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138 | RTSEMEVENT EventToSignal = pCritSect->s.EventToSignal;
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139 | if (RT_LIKELY(EventToSignal == NIL_RTSEMEVENT))
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140 | {
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141 | int rc = RTCritSectLeave(&pCritSect->s.Core);
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142 | AssertRC(rc);
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143 | }
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144 | else
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145 | {
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146 | pCritSect->s.EventToSignal = NIL_RTSEMEVENT;
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147 | int rc = RTCritSectLeave(&pCritSect->s.Core);
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148 | AssertRC(rc);
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149 | LogBird(("signalling %#x\n", EventToSignal));
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150 | rc = RTSemEventSignal(EventToSignal);
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151 | AssertRC(rc);
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152 | }
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153 |
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154 | #else /* !IN_RING3 */
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155 | Assert(VALID_PTR(pCritSect));
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156 | Assert(pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC);
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157 | Assert(pCritSect->s.Core.cNestings > 0);
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158 | Assert(pCritSect->s.Core.cLockers >= 0);
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159 | PVM pVM = pCritSect->s.CTXALLSUFF(pVM);
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160 | Assert(pVM);
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161 | Assert(pCritSect->s.Core.NativeThreadOwner == pVM->NativeThreadEMT);
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162 |
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163 | /*
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164 | * Deal with nested attempts first.
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165 | * (We're exploiting nesting to avoid queuing multiple R3 leaves for the same section.)
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166 | */
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167 | pCritSect->s.Core.cNestings--;
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168 | if (pCritSect->s.Core.cNestings > 0)
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169 | {
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170 | ASMAtomicDecS32(&pCritSect->s.Core.cLockers);
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171 | return;
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172 | }
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173 |
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174 | /*
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175 | * Try leave it.
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176 | */
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177 | if (pCritSect->s.Core.cLockers == 0)
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178 | {
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179 | STAM_PROFILE_ADV_STOP(&pCritSect->s.StatLocked, l);
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180 | ASMAtomicXchgSize(&pCritSect->s.Core.NativeThreadOwner, NIL_RTNATIVETHREAD);
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181 | if (ASMAtomicCmpXchgS32(&pCritSect->s.Core.cLockers, -1, 0))
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182 | return;
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183 |
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184 | /* darn, someone raced in on us. */
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185 | ASMAtomicXchgSize(&pCritSect->s.Core.NativeThreadOwner, pVM->NativeThreadEMT);
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186 | STAM_PROFILE_ADV_START(&pCritSect->s.StatLocked, l);
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187 | }
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188 | pCritSect->s.Core.cNestings = 1;
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189 |
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190 | /*
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191 | * Queue the request.
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192 | */
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193 | RTUINT i = pVM->pdm.s.cQueuedCritSectLeaves++;
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194 | LogFlow(("PDMCritSectLeave: [%d]=%p => R3\n", i, pCritSect));
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195 | AssertFatal(i < RT_ELEMENTS(pVM->pdm.s.apQueuedCritSectsLeaves));
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196 | pVM->pdm.s.apQueuedCritSectsLeaves[i] = MMHyperCCToR3(pVM, pCritSect);
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197 | VM_FF_SET(pVM, VM_FF_PDM_CRITSECT);
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198 | VM_FF_SET(pVM, VM_FF_TO_R3);
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199 | STAM_COUNTER_INC(&pVM->pdm.s.StatQueuedCritSectLeaves);
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200 | STAM_COUNTER_INC(&pCritSect->s.StatContentionR0GCUnlock);
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201 | #endif
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202 | }
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203 |
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204 |
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205 | /**
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206 | * Checks the caller is the owner of the critical section.
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207 | *
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208 | * @returns true if owner.
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209 | * @returns false if not owner.
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210 | * @param pCritSect The critical section.
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211 | */
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212 | PDMDECL(bool) PDMCritSectIsOwner(PCPDMCRITSECT pCritSect)
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213 | {
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214 | #ifdef IN_RING3
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215 | return RTCritSectIsOwner(&pCritSect->s.Core);
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216 | #else
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217 | PVM pVM = pCritSect->s.CTXALLSUFF(pVM);
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218 | Assert(pVM);
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219 | return pCritSect->s.Core.NativeThreadOwner == pVM->NativeThreadEMT;
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220 | #endif
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221 | }
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222 |
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223 |
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224 | /**
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225 | * Checks if a critical section is initialized or not.
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226 | *
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227 | * @returns true if initialized.
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228 | * @returns false if not initialized.
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229 | * @param pCritSect The critical section.
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230 | */
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231 | PDMDECL(bool) PDMCritSectIsInitialized(PCPDMCRITSECT pCritSect)
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232 | {
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233 | return pCritSect->s.Core.u32Magic == RTCRITSECT_MAGIC;
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234 | }
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235 |
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