Changeset 91808 in vbox for trunk

Timestamp:

Oct 18, 2021 9:20:07 AM (3 years ago)

Author:

vboxsync

Message:

VMM/PDMCritSect: Don't preempt while on custom stack. bugref:10124

Location:

trunk/src/VBox/VMM

Files:

• Makefile.kmk (modified) (1 diff)
• VMMAll/PDMAllCritSect.cpp (modified) (6 diffs)
• VMMR0/VMMR0StackBack-darwin.asm (added)

trunk/src/VBox/VMM/Makefile.kmk

@@ -570 +570 @@
 VMMR0_SOURCES.x86 = \
         VMMR0/VMMR0JmpA-x86.asm
+VMMR0_SOURCES.darwin.amd64 = \
+        VMMR0/VMMR0StackBack-darwin.asm
 
 VMMR0_LIBS = \

trunk/src/VBox/VMM/VMMAll/PDMAllCritSect.cpp

@@ -418 +418 @@
 
 
+#if defined(VMM_R0_SWITCH_STACK) && defined(IN_RING0)
+/**
+ * We must be on kernel stack before disabling preemption, thus this wrapper.
+ */
+DECLASM(int) StkBack_pdmR0CritSectEnterContendedOnKrnlStk(PVMCC pVM, PVMCPUCC pVCpu, PPDMCRITSECT pCritSect,
+                                                          RTNATIVETHREAD hNativeSelf, int rcBusy, PCRTLOCKVALSRCPOS pSrcPos)
+{
+    VMMR0EMTBLOCKCTX Ctx;
+    int rc = VMMR0EmtPrepareToBlock(pVCpu, rcBusy, __FUNCTION__, pCritSect, &Ctx);
+    if (rc == VINF_SUCCESS)
+    {
+        Assert(RTThreadPreemptIsEnabled(NIL_RTTHREAD));
+
+        rc = pdmR3R0CritSectEnterContended(pVM, pVCpu, pCritSect, hNativeSelf, pSrcPos, rcBusy);
+
+        VMMR0EmtResumeAfterBlocking(pVCpu, &Ctx);
+    }
+    else
+        STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLockBusy);
+    return rc;
+}
+decltype(StkBack_pdmR0CritSectEnterContendedOnKrnlStk) pdmR0CritSectEnterContendedOnKrnlStk;
+#endif
+
+
 /**
  * Common worker for the debug and normal APIs.
@@ -518 +543 @@
     if (pVCpu)
     {
+#  ifndef VMM_R0_SWITCH_STACK
         VMMR0EMTBLOCKCTX Ctx;
         int rc = VMMR0EmtPrepareToBlock(pVCpu, rcBusy, __FUNCTION__, pCritSect, &Ctx);
@@ -531 +557 @@
             STAM_REL_COUNTER_INC(&pCritSect->s.StatContentionRZLockBusy);
         return rc;
+#  else
+        return pdmR0CritSectEnterContendedOnKrnlStk(pVM, pVCpu, pCritSect, hNativeSelf, rcBusy, pSrcPos);
+#  endif
     }
 
@@ -778 +807 @@
 #endif /* IN_RING3 */
 
+
+#if defined(VMM_R0_SWITCH_STACK) && defined(IN_RING0)
+/**
+ * We must be on kernel stack before disabling preemption, thus this wrapper.
+ */
+DECLASM(int) StkBack_pdmR0CritSectLeaveSignallingOnKrnlStk(PVMCC pVM, PVMCPUCC pVCpu, PPDMCRITSECT pCritSect,
+                                                           int32_t const cLockers, SUPSEMEVENT const hEventToSignal)
+{
+    VMMR0EMTBLOCKCTX    Ctx;
+    bool                fLeaveCtx = false;
+    if (cLockers < 0)
+        AssertMsg(cLockers == -1, ("cLockers=%d\n", cLockers));
+    else
+    {
+        /* Someone is waiting, wake up one of them. */
+        Assert(cLockers < _8K);
+        SUPSEMEVENT hEvent = (SUPSEMEVENT)pCritSect->s.Core.EventSem;
+        if (!RTSemEventIsSignalSafe() && (pVCpu = VMMGetCpu(pVM)) != NULL)
+        {
+            int rc = VMMR0EmtPrepareToBlock(pVCpu, VINF_SUCCESS, __FUNCTION__, pCritSect, &Ctx);
+            VMM_ASSERT_RELEASE_MSG_RETURN(pVM, RT_SUCCESS(rc), ("rc=%Rrc\n", rc), rc);
+            fLeaveCtx = true;
+        }
+        int rc = SUPSemEventSignal(pVM->pSession, hEvent);
+        AssertRC(rc);
+    }
+
+    /*
+     * Signal exit event.
+     */
+    if (RT_LIKELY(hEventToSignal == NIL_SUPSEMEVENT))
+    { /* likely */ }
+    else
+    {
+        if (!fLeaveCtx && pVCpu != NULL && !RTSemEventIsSignalSafe() && (pVCpu = VMMGetCpu(pVM)) != NULL)
+        {
+            int rc = VMMR0EmtPrepareToBlock(pVCpu, VINF_SUCCESS, __FUNCTION__, pCritSect, &Ctx);
+            VMM_ASSERT_RELEASE_MSG_RETURN(pVM, RT_SUCCESS(rc), ("rc=%Rrc\n", rc), rc);
+            fLeaveCtx = true;
+        }
+        Log8(("Signalling %#p\n", hEventToSignal));
+        int rc = SUPSemEventSignal(pVM->pSession, hEventToSignal);
+        AssertRC(rc);
+    }
+
+    /*
+     * Restore HM context if needed.
+     */
+    if (!fLeaveCtx)
+    { /* contention should be unlikely */ }
+    else
+        VMMR0EmtResumeAfterBlocking(pVCpu, &Ctx);
+
+# ifdef DEBUG_bird
+    VMMTrashVolatileXMMRegs();
+# endif
+    return VINF_SUCCESS;
+}
+decltype(StkBack_pdmR0CritSectLeaveSignallingOnKrnlStk) pdmR0CritSectLeaveSignallingOnKrnlStk;
+#endif
 
 /**
@@ -934 +1023 @@
         if (!fQueueIt)
         {
+# ifndef VMM_R0_SWITCH_STACK
             VMMR0EMTBLOCKCTX    Ctx;
             bool                fLeaveCtx = false;
@@ -979 +1069 @@
                 VMMR0EmtResumeAfterBlocking(pVCpu, &Ctx);
 
-# ifdef DEBUG_bird
+#  ifdef DEBUG_bird
             VMMTrashVolatileXMMRegs();
-# endif
+#  endif
             return VINF_SUCCESS;
+# else
+            return pdmR0CritSectLeaveSignallingOnKrnlStk(pVM, pVCpu, pCritSect, cLockers, hEventToSignal);
+# endif
         }