So why implement this code path if we have nothing that hits it? Best regards, Alex Ionescu
On Fri, Apr 14, 2017 at 4:18 AM, <tfa...@svn.reactos.org> wrote: > Author: tfaber > Date: Fri Apr 14 11:18:22 2017 > New Revision: 74305 > > URL: http://svn.reactos.org/svn/reactos?rev=74305&view=rev > Log: > [NTOS:KE] > - Gracefully handle page faults during V86 code execution. This is a bit > of a hack because with our limited use of V86 code it is unclear how a page > fault can even occur. > CORE-12993 #resolve > > Modified: > trunk/reactos/ntoskrnl/include/internal/i386/ke.h > trunk/reactos/ntoskrnl/ke/i386/traphdlr.c > trunk/reactos/ntoskrnl/vdm/vdmexec.c > > Modified: trunk/reactos/ntoskrnl/include/internal/i386/ke.h > URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ > ntoskrnl/include/internal/i386/ke.h?rev=74305&r1=74304&r2=74305&view=diff > ============================================================ > ================== > --- trunk/reactos/ntoskrnl/include/internal/i386/ke.h [iso-8859-1] > (original) > +++ trunk/reactos/ntoskrnl/include/internal/i386/ke.h [iso-8859-1] Fri > Apr 14 11:18:22 2017 > @@ -478,6 +478,12 @@ > NTAPI > VdmDispatchBop( > IN PKTRAP_FRAME TrapFrame > +); > + > +BOOLEAN > +NTAPI > +VdmDispatchPageFault( > + _In_ PKTRAP_FRAME TrapFrame > ); > > BOOLEAN > > Modified: trunk/reactos/ntoskrnl/ke/i386/traphdlr.c > URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ > ntoskrnl/ke/i386/traphdlr.c?rev=74305&r1=74304&r2=74305&view=diff > ============================================================ > ================== > --- trunk/reactos/ntoskrnl/ke/i386/traphdlr.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/ke/i386/traphdlr.c [iso-8859-1] Fri Apr 14 > 11:18:22 2017 > @@ -1304,8 +1304,20 @@ > UNIMPLEMENTED_FATAL(); > } > #endif > + > /* Check for VDM trap */ > - ASSERT((KiVdmTrap(TrapFrame)) == FALSE); > + if (KiVdmTrap(TrapFrame)) > + { > + DPRINT1("VDM PAGE FAULT at %lx:%lx for address %lx\n", > + TrapFrame->SegCs, TrapFrame->Eip, Cr2); > + if (VdmDispatchPageFault(TrapFrame)) > + { > + /* Return and end VDM execution */ > + DPRINT1("VDM page fault with status 0x%lx resolved\n", > Status); > + KiEoiHelper(TrapFrame); > + } > + DPRINT1("VDM page fault with status 0x%lx NOT resolved\n", > Status); > + } > > /* Either kernel or user trap (non VDM) so dispatch exception */ > if (Status == STATUS_ACCESS_VIOLATION) > > Modified: trunk/reactos/ntoskrnl/vdm/vdmexec.c > URL: http://svn.reactos.org/svn/reactos/trunk/reactos/ > ntoskrnl/vdm/vdmexec.c?rev=74305&r1=74304&r2=74305&view=diff > ============================================================ > ================== > --- trunk/reactos/ntoskrnl/vdm/vdmexec.c [iso-8859-1] (original) > +++ trunk/reactos/ntoskrnl/vdm/vdmexec.c [iso-8859-1] Fri Apr 14 > 11:18:22 2017 > @@ -239,7 +239,7 @@ > KeLowerIrql(OldIrql); > return STATUS_INVALID_SYSTEM_SERVICE; > } > - > + > /* Now do the VDM Swap */ > VdmSwapContext(VdmFrame, &VdmTib->MonitorContext, &VdmContext); > > @@ -269,7 +269,7 @@ > > /* Make a copy of the monitor context */ > Context = VdmTib->MonitorContext; > - > + > /* Check if V86 mode was enabled or the trap was edited */ > if ((Context.EFlags & EFLAGS_V86_MASK) || (Context.SegCs & > FRAME_EDITED)) > { > @@ -291,7 +291,7 @@ > /* Remove real IF flag */ > VdmTib->VdmContext.EFlags &= ~EFLAGS_INTERRUPT_MASK; > } > - > + > /* Turn off VIP and VIF */ > TrapFrame->EFlags &= ~(EFLAGS_VIP | EFLAGS_VIF); > VdmTib->VdmContext.EFlags &= ~(EFLAGS_VIP | EFLAGS_VIF); > @@ -362,4 +362,45 @@ > return TRUE; > } > > - > +BOOLEAN > +NTAPI > +VdmDispatchPageFault( > + _In_ PKTRAP_FRAME TrapFrame) > +{ > + NTSTATUS Status; > + PVDM_TIB VdmTib; > + > + PAGED_CODE(); > + > + /* Get the VDM TIB so we can terminate V86 execution */ > + Status = VdmpGetVdmTib(&VdmTib); > + if (!NT_SUCCESS(Status)) > + { > + /* Not a proper VDM fault, keep looking */ > + DPRINT1("VdmDispatchPageFault: no VDM TIB, Vdm=%p\n", > NtCurrentTeb()->Vdm); > + return FALSE; > + } > + > + /* Must be coming from V86 code */ > + ASSERT(TrapFrame->EFlags & EFLAGS_V86_MASK); > + > + _SEH2_TRY > + { > + /* Fill out a VDM Event */ > + VdmTib->EventInfo.Event = VdmMemAccess; > + VdmTib->EventInfo.InstructionSize = 0; > + > + /* End VDM Execution */ > + VdmEndExecution(TrapFrame, VdmTib); > + } > + _SEH2_EXCEPT(EXCEPTION_EXECUTE_HANDLER) > + { > + Status = _SEH2_GetExceptionCode(); > + } > + _SEH2_END; > + > + /* Consider the exception handled if we succeeded */ > + DPRINT1("VdmDispatchPageFault EFlags %lx exit with 0x%lx\n", > TrapFrame->EFlags, Status); > + return NT_SUCCESS(Status); > +} > + > > >
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