Changeset 51325 in vbox for trunk/src/VBox/Additions/WINNT/Graphics/Video

Timestamp:

May 21, 2014 1:30:19 PM (11 years ago)

Author:

vboxsync

Message:

wddm: fix IRQ handling racing

File:

• trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp (modified) (2 diffs)

trunk/src/VBox/Additions/WINNT/Graphics/Video/mp/wddm/VBoxMPWddm.cpp

@@ -1462 +1462 @@
 
     do {
+        /* re-read flags right here to avoid host-guest racing,
+         * i.e. the situation:
+         * 1. guest reads flags ant it is HGSMIHOSTFLAGS_IRQ, i.e. HGSMIHOSTFLAGS_GCOMMAND_COMPLETED no set
+         * 2. host completes guest command, sets the HGSMIHOSTFLAGS_GCOMMAND_COMPLETED and raises IRQ
+         * 3. guest clleans IRQ and exits  */
+        flags = VBoxCommonFromDeviceExt(pDevExt)->hostCtx.pfHostFlags->u32HostFlags;
+
         if (flags & HGSMIHOSTFLAGS_GCOMMAND_COMPLETED)
         {
@@ -1506 +1513 @@
         else
             break;
-
-        flags = VBoxCommonFromDeviceExt(pDevExt)->hostCtx.pfHostFlags->u32HostFlags;
-
     } while (1);