Changeset 60660 in vbox for trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TrapRmV86Init.c

Timestamp:

Apr 22, 2016 4:45:50 PM (9 years ago)

Author:

vboxsync

Message:

bs3kit: Don't try override IVT[0x6d] as it turns out real VGA BIOSes likes using it and it may totally blow up INT 10h.

File:

• trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TrapRmV86Init.c (modified) (1 diff)

trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-TrapRmV86Init.c

@@ -87 +87 @@
      * cannot move the IVT from its default location.  So, modify it in place.
      *
-     * Note! We must keep int 10h working, which is easy since the CPU does
+     * Note! We must keep INT 10h working, which is easy since the CPU does
      *       use it (well, it's been reserved for 30+ years).
+     *       Turns out we must not hook INT 6Dh either then, as some real VGA
+     *       BIOS installs their INT 10h handler there as well, and seemingly
+     *       must be using it internally or something.
      */
     for (iIvt = 0; iIvt < 256; iIvt++)
-        if (iIvt != 0x10 && iIvt != BS3_TRAP_SYSCALL)
+        if (iIvt != 0x10 && iIvt != 0x6d && iIvt != BS3_TRAP_SYSCALL)
         {
             paIvt[iIvt].off = (uint16_t)(uintptr_t)Bs3TrapRmV86GenericEntries + iIvt * 8;