Changeset 97333 in vbox for trunk/src/VBox/VMM

Timestamp:

Oct 28, 2022 2:16:35 PM (2 years ago)

Author:

vboxsync

Message:

VMM/IEM: Disable two incorrect assertions about EIP when fetching opcode bytes in 16-bit mode.

File:

• trunk/src/VBox/VMM/VMMAll/IEMAll.cpp (modified) (2 diffs)

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

@@ -765 +765 @@
         {
             GCPtrFirst = pVCpu->cpum.GstCtx.eip + (offBuf - (uint32_t)(int32_t)pVCpu->iem.s.offCurInstrStart);
-            Assert(!(GCPtrFirst & ~(uint32_t)UINT16_MAX) || pVCpu->iem.s.enmCpuMode == IEMMODE_32BIT);
+            /* Assert(!(GCPtrFirst & ~(uint32_t)UINT16_MAX) || pVCpu->iem.s.enmCpuMode == IEMMODE_32BIT); - this is allowed */
             if (RT_LIKELY((uint32_t)GCPtrFirst <= pVCpu->cpum.GstCtx.cs.u32Limit))
             { /* likely */ }
-            else
+            else /** @todo For CPUs older than the 386, we should not generate #GP here but wrap around! */
                 iemRaiseSelectorBoundsJmp(pVCpu, X86_SREG_CS, IEM_ACCESS_INSTRUCTION);
             cbMaxRead = pVCpu->cpum.GstCtx.cs.u32Limit - (uint32_t)GCPtrFirst + 1;
@@ -1002 +1002 @@
     {
         uint32_t GCPtrNext32 = pVCpu->cpum.GstCtx.eip;
-        Assert(!(GCPtrNext32 & ~(uint32_t)UINT16_MAX) || pVCpu->iem.s.enmCpuMode == IEMMODE_32BIT);
+        /* Assert(!(GCPtrNext32 & ~(uint32_t)UINT16_MAX) || pVCpu->iem.s.enmCpuMode == IEMMODE_32BIT); - this is allowed */
         GCPtrNext32 += pVCpu->iem.s.cbOpcode;
         if (GCPtrNext32 > pVCpu->cpum.GstCtx.cs.u32Limit)
+            /** @todo For CPUs older than the 386, we should not generate #GP here but wrap around! */
             return iemRaiseSelectorBounds(pVCpu, X86_SREG_CS, IEM_ACCESS_INSTRUCTION);
         cbToTryRead = pVCpu->cpum.GstCtx.cs.u32Limit - GCPtrNext32 + 1;