Changeset 96914 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Sep 28, 2022 10:41:01 AM (2 years ago)

Author:

vboxsync

Message:

IEM: FNSTENV must clear pending math exceptions to avoid exception loops.

File:

• trunk/src/VBox/VMM/VMMAll/IEMAllCImpl.cpp (modified) (1 diff)

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

@@ -9306 +9306 @@
         return rcStrict;
 
+    /* Mask all math exceptions. Any possibly pending exceptions will be cleared. */
+    PX86FXSTATE pFpuCtx = &pVCpu->cpum.GstCtx.XState.x87;
+    pFpuCtx->FCW |=   X86_FCW_PM | X86_FCW_UM | X86_FCW_OM | X86_FCW_ZM | X86_FCW_DM | X86_FCW_IM;
+    pFpuCtx->FSW &= ~(X86_FSW_PE | X86_FSW_UE | X86_FSW_OE | X86_FSW_ZE | X86_FSW_DE | X86_FSW_IE | X86_FSW_ES);
+    iemHlpUsedFpu(pVCpu);
+
     /* Note: C0, C1, C2 and C3 are documented as undefined, we leave them untouched! */
     iemRegAddToRipAndClearRF(pVCpu, cbInstr);