Changeset 83505 in vbox for trunk/src

Timestamp:

Apr 1, 2020 3:30:45 PM (5 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

136799

Message:

VMSVGA: Fixed a possible race which could cause a guest to endlessly wait for SVGA_REG_BUSY to be clear.

File:

• trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Graphics/DevVGA-SVGA.cpp

@@ -3262 +3262 @@
 static void vmsvgaR3FifoSetNotBusy(PPDMDEVINS pDevIns, PVGASTATE pThis, PVGASTATECC pThisCC, PVMSVGAR3STATE pSVGAState, uint32_t offFifoMin)
 {
-    ASMAtomicAndU32(&pThis->svga.fBusy, ~VMSVGA_BUSY_F_FIFO);
+    ASMAtomicAndU32(&pThis->svga.fBusy, ~(VMSVGA_BUSY_F_FIFO | VMSVGA_BUSY_F_EMT_FORCE));
     if (VMSVGA_IS_VALID_FIFO_REG(SVGA_FIFO_BUSY, offFifoMin))
         vmsvgaHCSafeFifoBusyRegUpdate(pThis, pThisCC, pThis->svga.fBusy != 0);
@@ -3843 +3843 @@
          * Mark the FIFO as busy.
          */
-        ASMAtomicWriteU32(&pThis->svga.fBusy, VMSVGA_BUSY_F_FIFO);
+        ASMAtomicWriteU32(&pThis->svga.fBusy, VMSVGA_BUSY_F_FIFO);  // Clears VMSVGA_BUSY_F_EMT_FORCE!
         if (VMSVGA_IS_VALID_FIFO_REG(SVGA_FIFO_BUSY, offFifoMin))
             ASMAtomicWriteU32(&pFIFO[SVGA_FIFO_BUSY], true);