Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1679 insertions, 0 deletions

diff --git a/src/VBox/Additions/common/VBoxGuest/VBoxGuestA-os2.asm b/src/VBox/Additions/common/VBoxGuest/VBoxGuestA-os2.asm
new file mode 100644
index 00000000..12df6b42
--- /dev/null
+++ b/src/VBox/Additions/common/VBoxGuest/VBoxGuestA-os2.asm
@@ -0,0 +1,1679 @@
+; $Id: VBoxGuestA-os2.asm $
+;; @file
+; VBoxGuest - OS/2 assembly file, the first file in the link.
+;
+
+;
+; Copyright (C) 2007-2023 Oracle and/or its affiliates.
+;
+; This file is part of VirtualBox base platform packages, as
+; available from https://www.virtualbox.org.
+;
+; This program is free software; you can redistribute it and/or
+; modify it under the terms of the GNU General Public License
+; as published by the Free Software Foundation, in version 3 of the
+; License.
+;
+; This program is distributed in the hope that it will be useful, but
+; WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+; General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program; if not, see <https://www.gnu.org/licenses>.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
+; in the VirtualBox distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
+;-----------------------------------------------------------------------------
+; This code is based on:
+;
+; VBoxDrv - OS/2 assembly file, the first file in the link.
+;
+; Copyright (c) 2007-2010 knut st. osmundsen <bird-src-spam@anduin.net>
+;
+; Permission is hereby granted, free of charge, to any person
+; obtaining a copy of this software and associated documentation
+; files (the "Software"), to deal in the Software without
+; restriction, including without limitation the rights to use,
+; copy, modify, merge, publish, distribute, sublicense, and/or sell
+; copies of the Software, and to permit persons to whom the
+; Software is furnished to do so, subject to the following
+; conditions:
+;
+; The above copyright notice and this permission notice shall be
+; included in all copies or substantial portions of the Software.
+;
+; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+; OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+; NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+; HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+; WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+; OTHER DEALINGS IN THE SOFTWARE.
+;
+
+
+;*******************************************************************************
+;* Header Files                                                                *
+;*******************************************************************************
+%define RT_INCL_16BIT_SEGMENTS
+%include "iprt/asmdefs.mac"
+%include "iprt/err.mac"
+%include "VBox/VBoxGuest.mac"
+
+
+;*******************************************************************************
+;* Structures and Typedefs                                                     *
+;*******************************************************************************
+;;
+; Request packet header.
+struc PKTHDR
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+endstruc
+
+
+;;
+; Init request packet - input.
+struc PKTINITIN
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+
+    .data_1 resb 1
+    .fpfnDevHlp resd 1
+    .fpszArgs   resd 1
+    .data_2 resb 1
+endstruc
+
+;;
+; Init request packet - output.
+struc PKTINITOUT
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+
+    .cUnits resb 1                      ; block devs only.
+    .cbCode16 resw 1
+    .cbData16 resw 1
+    .fpaBPBs  resd 1                    ; block devs only.
+    .data_2 resb 1
+endstruc
+
+;;
+; Open request packet.
+struc PKTOPEN
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+    .sfn    resw 1
+endstruc
+
+;;
+; Close request packet.
+struc PKTCLOSE
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+    .sfn    resw 1
+endstruc
+
+;;
+; IOCtl request packet.
+struc PKTIOCTL
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+
+    .cat    resb 1
+    .fun    resb 1
+    .pParm  resd 1
+    .pData  resd 1
+    .sfn    resw 1
+    .cbParm resw 1
+    .cbData resw 1
+endstruc
+
+;;
+; Read/Write request packet
+struc PKTRW
+    .cb     resb 1
+    .unit   resb 1
+    .cmd    resb 1
+    .status resw 1
+    .res1   resd 1
+    .link   resd 1
+
+    .media  resb 1
+    .PhysTrans resd 1
+    .cbTrans resw 1
+    .start  resd 1
+    .sfn    resw 1
+endstruc
+
+
+;*******************************************************************************
+;*  Defined Constants And Macros                                               *
+;*******************************************************************************
+; Some devhdr.inc stuff.
+%define DEVLEV_3                0180h
+%define DEV_30                  0800h
+%define DEV_IOCTL               4000h
+%define DEV_CHAR_DEV            8000h
+
+%define DEV_16MB                0002h
+%define DEV_IOCTL2              0001h
+
+; Some dhcalls.h stuff.
+%define DevHlp_VirtToLin        05bh
+%define DevHlp_SAVE_MESSAGE     03dh
+%define DevHlp_EOI              031h
+%define DevHlp_SetIRQ           01bh
+%define DevHlp_PhysToVirt       015h
+
+; Fast IOCtl category, also defined in VBoxGuest.h
+%define VBGL_IOCTL_CATEGORY_FAST    0c3h
+
+;;
+; Got some nasm/link trouble, so emit the stuff ourselves.
+; @param    %1      Must be a GLOBALNAME.
+%macro JMP32TO16 1
+    ;jmp far dword NAME(%1) wrt CODE16
+    db      066h
+    db      0eah
+    dw      NAME(%1) wrt CODE16
+    dw      CODE16
+%endmacro
+
+;;
+; Got some nasm/link trouble, so emit the stuff ourselves.
+; @param    %1      Must be a GLOBALNAME.
+%macro JMP16TO32 1
+    ;jmp far dword NAME(%1) wrt FLAT
+    db      066h
+    db      0eah
+    dd      NAME(%1) ;wrt FLAT
+    dw      TEXT32 wrt FLAT
+%endmacro
+
+
+;*******************************************************************************
+;* External Symbols                                                            *
+;*******************************************************************************
+segment CODE16
+extern DOS16OPEN
+extern DOS16CLOSE
+extern DOS16WRITE
+extern DOS16DEVIOCTL2
+segment TEXT32
+extern KernThunkStackTo32
+extern KernThunkStackTo16
+
+extern NAME(vgdrvOS2Init)
+extern NAME(vgdrvOS2Open)
+extern NAME(vgdrvOS2Close)
+extern NAME(vgdrvOS2IOCtl)
+extern NAME(vgdrvOS2IOCtlFast)
+extern NAME(vgdrvOS2IDCConnect)
+extern NAME(VGDrvOS2IDCService)
+extern NAME(vgdrvOS2ISR)
+
+
+segment DATA16
+
+;;
+; Device headers. The first one is the one we'll be opening and the
+; latter is only used for 32-bit initialization.
+GLOBALNAME g_VBoxGuestHdr1
+    dw  NAME(g_VBoxGuestHdr2) wrt DATA16            ; NextHeader.off
+    dw  DATA16                                      ; NextHeader.sel
+    dw  DEVLEV_3 | DEV_30 | DEV_CHAR_DEV | DEV_IOCTL; SDevAtt
+    dw  NAME(VGDrvOS2Entrypoint) wrt CODE16         ; StrategyEP
+    dw  NAME(VGDrvOS2IDC) wrt CODE16                ; IDCEP
+    db  'vboxgst$'                                  ; DevName
+    dw  0                                           ; SDevProtCS
+    dw  0                                           ; SDevProtDS
+    dw  0                                           ; SDevRealCS
+    dw  0                                           ; SDevRealDS
+    dd  DEV_16MB | DEV_IOCTL2                       ; SDevCaps
+
+align 4
+GLOBALNAME g_VBoxGuestHdr2
+    dd  0ffffffffh                                  ; NextHeader (NIL)
+    dw  DEVLEV_3 | DEV_30 | DEV_CHAR_DEV            ; SDevAtt
+    dw  NAME(vgdrvOS2InitEntrypoint) wrt CODE16     ; StrategyEP
+    dw  0                                           ; IDCEP
+    db  'vboxgs1$'                                  ; DevName
+    dw  0                                           ; SDevProtCS
+    dw  0                                           ; SDevProtDS
+    dw  0                                           ; SDevRealCS
+    dw  0                                           ; SDevRealDS
+    dd  DEV_16MB | DEV_IOCTL2                       ; SDevCaps
+
+
+;; Tristate 32-bit initialization indicator [0 = need init, -1 = init failed, 1 init succeeded].
+; Check in the open path of the primary driver. The secondary driver will
+; open the primary one during it's init and thereby trigger the 32-bit init.
+GLOBALNAME g_fInitialized
+    db 0
+
+align 4
+;; Pointer to the device helper service routine
+; This is set during the initialization of the 2nd device driver.
+GLOBALNAME g_fpfnDevHlp
+    dd 0
+
+
+;; vgdrvFindAdapter Output
+; @{
+
+;; The MMIO base of the VMMDev.
+GLOBALNAME g_PhysMMIOBase
+    dd 0
+;; The size of the MMIO memory of the VMMDev.
+GLOBALNAME g_cbMMIO
+    dd 0
+;; The I/O port base of the VMMDev.
+GLOBALNAME g_IOPortBase
+    dw 0
+;; The VMMDev Interrupt Line.
+GLOBALNAME g_bInterruptLine
+    db 0
+;; The PCI bus number returned by Find PCI Device.
+GLOBALNAME g_bPciBusNo
+    db 0
+;; The PCI Device No / Function Number returned by Find PCI Device.
+; (The upper 5 bits is the number, and the lower 3 the function.)
+GLOBALNAME g_bPciDevFunNo
+    db 0
+;; Flag that is set by the vboxgst$ init routine if VMMDev was found.
+; Both init routines must refuse loading the driver if the
+; device cannot be located.
+GLOBALNAME g_fFoundAdapter
+    db 0
+;; @}
+
+
+%ifdef DEBUG_READ
+;; Where we write to the log.
+GLOBALNAME g_offLogHead
+    dw 0
+;; Where we read from the log.
+GLOBALNAME g_offLogTail
+    dw 0
+;; The size of the log. (power of two!)
+%define LOG_SIZE 16384
+GLOBALNAME g_cchLogMax
+    dw LOG_SIZE
+;; The log buffer.
+GLOBALNAME g_szLog
+    times LOG_SIZE db 0
+%endif ; DEBUG_READ
+
+
+;
+; The init data.
+;
+segment DATA16_INIT
+GLOBALNAME g_InitDataStart
+
+;; Far pointer to the device argument.
+g_fpszArgs:
+    dd      0
+
+%if 0
+;; Message table for the Save_Message device helper.
+GLOBALNAME g_MsgTab
+    dw  1178                                        ; MsgId - 'MSG_REPLACEMENT_STRING'.
+    dw  1                                           ; cMsgStrings
+    dw  NAME(g_szInitText)                          ; MsgStrings[0]
+    dw  seg NAME(g_szInitText)
+%else
+;; Far pointer to DOS16WRITE (corrected set before called).
+; Just a temporary hack to work around a wlink issue.
+GLOBALNAME g_fpfnDos16Write
+    dw  DOS16WRITE
+    dw  seg DOS16WRITE
+%endif
+
+;; Size of the text currently in the g_szInitText buffer.
+GLOBALNAME g_cchInitText
+    dw      0
+;; The max size of text that can fit into the g_szInitText buffer.
+GLOBALNAME g_cchInitTextMax
+    dw      512
+;; The init text buffer.
+GLOBALNAME g_szInitText
+    times 512 db 0
+
+;; Message string that's written on failure.
+g_achLoadFailureMsg1:
+    db      0dh,0ah,'VBoxGuest: load failure no. '
+g_cchLoadFailureMsg1 EQU $ - g_achLoadFailureMsg1
+g_achLoadFailureMsg2:
+    db      '!',0dh,0ah
+g_cchLoadFailureMsg2 EQU $ - g_achLoadFailureMsg2
+
+
+;
+; The 16-bit code segment.
+;
+segment CODE16
+
+
+;;
+; The strategy entry point (vboxdrv$).
+;
+; ss:bx -> request packet
+; ds:si -> device header
+;
+; Can clobber any registers it likes except SP.
+;
+BEGINPROC VGDrvOS2Entrypoint
+    push    ebp
+    mov     ebp, esp
+    push    es                                      ; bp - 2
+    push    bx                                      ; bp - 4
+    and     sp, 0fffch
+
+    ;
+    ; Check for the most frequent first.
+    ;
+    cmp     byte [es:bx + PKTHDR.cmd], 10h          ; Generic IOCtl
+    jne near vgdrvOS2EP_NotGenIOCtl
+
+
+    ;
+    ; Generic I/O Control Request.
+    ;
+vgdrvOS2EP_GenIOCtl:
+
+    ; Fast IOCtl?
+    cmp     byte [es:bx + PKTIOCTL.cat], VBGL_IOCTL_CATEGORY_FAST
+    jne     vgdrvOS2EP_GenIOCtl_Other
+
+    ;
+    ; Fast IOCtl.
+    ;   DECLASM(int) vgdrvOS2IOCtlFast(uint16_t sfn, uint8_t iFunction, uint16_t *pcbParm)
+    ;
+vgdrvOS2EP_GenIOCtl_Fast:
+    mov     ax, [es:bx + PKTIOCTL.pData + 2]        ; LDT selector to flat address.
+    shr     ax, 3
+    shl     eax, 16
+    mov     ax, [es:bx + PKTIOCTL.pData]
+    push    eax                                     ; 08h - pointer to the rc buffer.
+
+    ; function.
+    movzx   edx, byte [es:bx + PKTIOCTL.fun]
+    push    edx                                     ; 04h
+
+    ; system file number.
+    movzx   eax, word [es:bx + PKTIOCTL.sfn]
+    push    eax                                     ; 00h
+
+    JMP16TO32 vgdrvOS2EP_GenIOCtl_Fast_32
+segment TEXT32
+GLOBALNAME vgdrvOS2EP_GenIOCtl_Fast_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code (don't cleanup the stack).
+    call    NAME(vgdrvOS2IOCtlFast)
+
+    ; switch back the stack.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    JMP32TO16 vgdrvOS2EP_GenIOCtl_Fast_32
+segment CODE16
+GLOBALNAME vgdrvOS2EP_GenIOCtl_Fast_16
+
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    or      eax, eax
+    jnz near vgdrvOS2EP_GeneralFailure
+
+    ; setup output stuff.
+    mov     edx, esp
+    mov     eax, [ss:edx + 0ch]                     ; output sizes.
+    mov     [es:bx + PKTIOCTL.cbParm], eax          ; update cbParm and cbData.
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+
+    mov     sp, bp
+    pop     ebp
+    retf
+
+    ;
+    ; Other IOCtl (slow)
+    ;
+vgdrvOS2EP_GenIOCtl_Other:
+    mov     eax, [es:bx +  PKTIOCTL.cbParm]         ; Load cbParm and cbData
+    push    eax                                     ; 1eh - in/out data size.
+                                                    ; 1ch - in/out parameter size.
+    push    edx                                     ; 18h - pointer to data size (filled in later).
+    push    ecx                                     ; 14h - pointer to param size (filled in later).
+
+    ; pData (convert to flat 32-bit)
+    mov     ax,  word [es:bx + PKTIOCTL.pData + 2]  ; selector
+    cmp     ax, 3                                   ; <= 3 -> nil selector...
+    jbe     .no_data
+    movzx   esi, word [es:bx + PKTIOCTL.pData]      ; offset
+    mov     dl, DevHlp_VirtToLin
+    call far [NAME(g_fpfnDevHlp)]
+    jc near vgdrvOS2EP_GeneralFailure
+    jmp     .finish_data
+.no_data:
+    xor     eax, eax
+.finish_data:
+    push    eax                                     ; 10h
+
+    ; pParm (convert to flat 32-bit)
+    mov     ax,  word [es:bx + PKTIOCTL.pParm + 2]  ; selector
+    cmp     ax, 3                                   ; <= 3 -> nil selector...
+    jbe     .no_parm
+    movzx   esi, word [es:bx + PKTIOCTL.pParm]      ; offset
+    mov     dl, DevHlp_VirtToLin
+    call far [NAME(g_fpfnDevHlp)]
+    jc near vgdrvOS2EP_GeneralFailure
+    jmp     .finish_parm
+.no_parm:
+    xor     eax, eax
+.finish_parm:
+    push    eax                                     ; 0ch
+
+    ; function.
+    movzx   edx, byte [es:bx + PKTIOCTL.fun]
+    push    edx                                     ; 08h
+
+    ; category.
+    movzx   ecx, byte [es:bx + PKTIOCTL.cat]
+    push    ecx                                     ; 04h
+
+    ; system file number.
+    movzx   eax, word [es:bx + PKTIOCTL.sfn]
+    push    eax                                     ; 00h
+
+    JMP16TO32 vgdrvOS2EP_GenIOCtl_Other_32
+segment TEXT32
+GLOBALNAME vgdrvOS2EP_GenIOCtl_Other_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; update in/out parameter pointers
+    lea     eax, [esp + 1ch]
+    mov     [esp + 14h], eax
+    lea     edx, [esp + 1eh]
+    mov     [esp + 18h], edx
+
+    ; call the C code (don't cleanup the stack).
+    call    NAME(vgdrvOS2IOCtl)
+
+    ; switch back the stack.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    JMP32TO16 vgdrvOS2EP_GenIOCtl_Other_16
+segment CODE16
+GLOBALNAME vgdrvOS2EP_GenIOCtl_Other_16
+
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    or      eax, eax
+    jnz near vgdrvOS2EP_GeneralFailure
+
+    ; setup output stuff.
+    mov     edx, esp
+    mov     eax, [ss:edx + 1ch]                     ; output sizes.
+    mov     [es:bx + PKTIOCTL.cbParm], eax          ; update cbParm and cbData.
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+
+    mov     sp, bp
+    pop     ebp
+    retf
+
+
+    ;
+    ; Less Performance Critical Requests.
+    ;
+vgdrvOS2EP_NotGenIOCtl:
+    cmp     byte [es:bx + PKTHDR.cmd], 0dh          ; Open
+    je      vgdrvOS2EP_Open
+    cmp     byte [es:bx + PKTHDR.cmd], 0eh          ; Close
+    je      vgdrvOS2EP_Close
+    cmp     byte [es:bx + PKTHDR.cmd], 00h          ; Init
+    je      vgdrvOS2EP_Init
+%ifdef DEBUG_READ
+    cmp     byte [es:bx + PKTHDR.cmd], 04h          ; Read
+    je near vgdrvOS2EP_Read
+%endif
+    jmp near vgdrvOS2EP_NotSupported
+
+
+    ;
+    ; Open Request. w/ ring-0 init.
+    ;
+vgdrvOS2EP_Open:
+    cmp     byte [NAME(g_fInitialized)], 1
+    jne     vgdrvOS2EP_OpenOther
+
+    ; First argument, the system file number.
+    movzx   eax, word [es:bx + PKTOPEN.sfn]
+    push    eax
+
+    JMP16TO32 vgdrvOS2EP_Open_32
+segment TEXT32
+GLOBALNAME vgdrvOS2EP_Open_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code.
+    call    NAME(vgdrvOS2Open)
+
+    ; switch back the stack.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    JMP32TO16 vgdrvOS2EP_Open_16
+segment CODE16
+GLOBALNAME vgdrvOS2EP_Open_16
+
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    or      eax, eax
+    jnz near vgdrvOS2EP_GeneralFailure
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+    jmp near vgdrvOS2EP_Done
+
+    ; Initializing or failed init?
+vgdrvOS2EP_OpenOther:
+    cmp     byte [NAME(g_fInitialized)], 0
+    jne     vgdrvOS2EP_OpenFailed
+
+    mov     byte [NAME(g_fInitialized)], -1
+    call    NAME(vgdrvRing0Init)
+    cmp     byte [NAME(g_fInitialized)], 1
+    je      vgdrvOS2EP_Open
+
+vgdrvOS2EP_OpenFailed:
+    mov     word [es:bx + PKTHDR.status], 0810fh    ; error, done, init failed.
+    jmp near vgdrvOS2EP_Done
+
+
+    ;
+    ; Close Request.
+    ;
+vgdrvOS2EP_Close:
+    ; First argument, the system file number.
+    movzx   eax, word [es:bx + PKTOPEN.sfn]
+    push    eax
+
+    JMP16TO32 vgdrvOS2EP_Close_32
+segment TEXT32
+GLOBALNAME vgdrvOS2EP_Close_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code.
+    call    NAME(vgdrvOS2Close)
+
+    ; switch back the stack.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    JMP32TO16 vgdrvOS2EP_Close_16
+segment CODE16
+GLOBALNAME vgdrvOS2EP_Close_16
+
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    or      eax, eax
+    jnz near vgdrvOS2EP_GeneralFailure
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+    jmp near vgdrvOS2EP_Done
+
+
+    ;
+    ; Init Request.
+    ; Find the VMMDev adapter so we can unload the driver (and avoid trouble) if not found.
+    ;
+vgdrvOS2EP_Init:
+    call    NAME(vgdrvFindAdapter)
+    test    ax, ax
+    jz      .ok
+    mov     word [es:bx + PKTHDR.status], 0810fh    ; error, done, init failed.
+    call    NAME(vgdrvOS2InitFlushText)
+    jmp     .next
+.ok:
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+.next:
+    mov     byte [es:bx + PKTINITOUT.cUnits], 0
+    mov     word [es:bx + PKTINITOUT.cbCode16], NAME(g_InitCodeStart) wrt CODE16
+    mov     word [es:bx + PKTINITOUT.cbData16], NAME(g_InitDataStart) wrt DATA16
+    mov     dword [es:bx + PKTINITOUT.fpaBPBs], 0
+    jmp near vgdrvOS2EP_Done
+
+
+%ifdef DEBUG_READ
+    ;
+    ; Read Request.
+    ; Return log data.
+    ;
+vgdrvOS2EP_Read:
+    ; Any log data available?
+    xor     dx, dx
+    mov     ax, [NAME(g_offLogTail)]
+    cmp     ax, [NAME(g_offLogHead)]
+    jz near .log_done
+
+    ; create a temporary mapping of the physical buffer. Docs claims it trashes nearly everything...
+    push    ebp
+    mov     cx, [es:bx + PKTRW.cbTrans]
+    push    cx
+    mov     ax, [es:bx + PKTRW.PhysTrans + 2]
+    mov     bx, [es:bx + PKTRW.PhysTrans]
+    mov     dh, 1
+    mov     dl, DevHlp_PhysToVirt
+    call far [NAME(g_fpfnDevHlp)]
+    pop     bx                                      ; bx = cbTrans
+    pop     ebp
+    jc near .log_phystovirt_failed
+                                                    ; es:di -> the output buffer.
+
+    ; setup the copy operation.
+    mov     ax, [NAME(g_offLogTail)]
+    xor     dx, dx                                  ; dx tracks the number of bytes copied.
+.log_loop:
+    mov     cx, [NAME(g_offLogHead)]
+    cmp     ax, cx
+    je      .log_done
+    jb      .log_loop_before
+    mov     cx, LOG_SIZE
+.log_loop_before:                                   ; cx = end offset
+    sub     cx, ax                                  ; cx = sequential bytes to copy.
+    cmp     cx, bx
+    jbe     .log_loop_min
+    mov     cx, bx                                  ; output buffer is smaller than available data.
+.log_loop_min:
+    mov     si, NAME(g_szLog)
+    add     si, ax                                  ; ds:si -> the log buffer.
+    add     dx, cx                                  ; update output counter
+    add     ax, cx                                  ; calc new offLogTail
+    and     ax, LOG_SIZE - 1
+    rep movsb                                       ; do the copy
+    mov     [NAME(g_offLogTail)], ax                ; commit the read.
+    jmp     .log_loop
+
+.log_done:
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    mov     word [es:bx + PKTRW.cbTrans], dx
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+    jmp near vgdrvOS2EP_Done
+
+.log_phystovirt_failed:
+    les     bx, [bp - 4]                            ; Reload the packet pointer.
+    jmp     vgdrvOS2EP_GeneralFailure
+%endif ; DEBUG_READ
+
+
+    ;
+    ; Return 'unknown command' error.
+    ;
+vgdrvOS2EP_NotSupported:
+    mov     word [es:bx + PKTHDR.status], 08103h    ; error, done, unknown command.
+    jmp     vgdrvOS2EP_Done
+
+    ;
+    ; Return 'general failure' error.
+    ;
+vgdrvOS2EP_GeneralFailure:
+    mov     word [es:bx + PKTHDR.status], 0810ch    ; error, done, general failure.
+    jmp     vgdrvOS2EP_Done
+
+    ;
+    ; Non-optimized return path.
+    ;
+vgdrvOS2EP_Done:
+    mov     sp, bp
+    pop     ebp
+    retf
+ENDPROC VGDrvOS2Entrypoint
+
+
+;;
+; The helper device entry point.
+;
+; This is only used to do the DosOpen on the main driver so we can
+; do ring-3 init and report failures.
+;
+GLOBALNAME vgdrvOS2InitEntrypoint
+    ; The only request we're servicing is the 'init' one.
+    cmp     word [es:bx + PKTHDR.cmd], 0
+    je near NAME(vgdrvOS2InitEntrypointServiceInitReq)
+
+    ; Ok, it's not the init request, just fail it.
+    mov     word [es:bx + PKTHDR.status], 08103h    ; error, done, unknown command.
+    retf
+
+
+;;
+; The OS/2 IDC entry point.
+;
+; This is only used to setup connection, the returned structure
+; will provide the entry points that we'll be using.
+;
+; @cproto  void far __cdecl VGDrvOS2IDC(VBOXGUESTOS2IDCCONNECT far *fpConnectInfo);
+;
+; @param   fpConnectInfo   [bp + 8]     Pointer to an VBOXGUESTOS2IDCCONNECT structure.
+;
+GLOBALNAME VGDrvOS2IDC
+    push    ebp                         ; bp -  0h
+    mov     ebp, esp
+    ; save everything we might touch.
+    push    es                          ; bp -  2h
+    push    ds                          ; bp -  4h
+    push    eax                         ; bp -  8h
+    push    ebx                         ; bp - 0ch
+    push    ecx                         ; bp - 10h
+    push    edx                         ; bp - 14h
+    and     sp, 0fffch
+
+    JMP16TO32 VGDrvOS2IDC_32
+segment TEXT32
+GLOBALNAME VGDrvOS2IDC_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code.
+    call    NAME(vgdrvOS2IDCConnect)
+
+    ;
+    ; Load the return buffer address into ds:ebx and setup the buffer.
+    ; (eax == u32Session)
+    ;
+    mov     cx, [ebp + 08h + 2]
+    mov     ds, cx
+    movzx   ebx, word [ebp + 08h]
+
+    mov     dword [ebx + VBGLOS2ATTACHDD.u32Version       ], VBGL_IOC_VERSION
+    mov     dword [ebx + VBGLOS2ATTACHDD.u32Session       ], eax
+    mov     dword [ebx + VBGLOS2ATTACHDD.pfnServiceEP     ], NAME(VGDrvOS2IDCService)
+    mov     word  [ebx + VBGLOS2ATTACHDD.fpfnServiceEP    ], NAME(VGDrvOS2IDCService16) wrt CODE16
+    mov     word  [ebx + VBGLOS2ATTACHDD.fpfnServiceEP + 2], CODE16
+    mov     word  [ebx + VBGLOS2ATTACHDD.fpfnServiceAsmEP ], NAME(VGDrvOS2IDCService16Asm) wrt CODE16
+    mov     word  [ebx + VBGLOS2ATTACHDD.fpfnServiceAsmEP+2],CODE16
+
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+
+    ; switch back the stack.
+    call    KernThunkStackTo16
+
+    JMP32TO16 VGDrvOS2IDC_16
+segment CODE16
+GLOBALNAME VGDrvOS2IDC_16
+
+    ; restore.
+    lea     sp, [bp - 14h]
+    pop     edx
+    pop     ecx
+    pop     ebx
+    pop     eax
+    pop     ds
+    pop     es
+    pop     ebp
+    retf
+ENDPROC VGDrvOS2IDC
+
+
+;;
+; The 16-bit IDC entry point, cdecl.
+;
+; All this does is thunking the request into something that fits
+; the 32-bit IDC service routine.
+;
+;
+; @returns VBox status code.
+; @param   u32Session          bp +  8h - The above session handle.
+; @param   iFunction           bp + 0ch - The requested function.
+; @param   fpReqHdr            bp + 0eh - The input/output data buffer. The caller ensures that this
+;                                         cannot be swapped out, or that it's acceptable to take a
+;                                         page in fault in the current context. If the request doesn't
+;                                         take input or produces output, passing NULL is okay.
+; @param   cbReq               bp + 12h - The size of the data buffer.
+;
+; @cproto long far __cdecl VGDrvOS2IDCService16(uint32_t u32Session, uint16_t iFunction, void far *fpReqHdr, uint16_t cbReq);
+;
+GLOBALNAME VGDrvOS2IDCService16
+    push    ebp                         ; bp -  0h
+    mov     ebp, esp
+    push    es                          ; bp -  2h
+    push    ds                          ; bp -  4h
+    push    ecx                         ; bp -  8h
+    push    edx                         ; bp - 0ch
+    push    esi                         ; bp - 10h
+    and     sp, 0fffch                  ; align the stack.
+
+    ; locals
+    push    dword 0                     ; esp + 18h (dd): cbDataReturned
+
+    ; load our ds (for g_fpfnDevHlp).
+    mov     ax, DATA16
+    mov     ds, ax
+
+    ;
+    ; Create the call frame before switching.
+    ;
+    movzx   ecx, word [bp + 12h]
+    push    ecx                         ; esp + 10h:    cbData
+
+    ; thunk data argument if present.
+    mov     ax,  [bp + 0eh + 2]         ; selector
+    cmp     ax, 3                       ; <= 3 -> nil selector...
+    jbe     .no_data
+    movzx   esi, word [bp + 0eh]        ; offset
+    mov     dl, DevHlp_VirtToLin
+    call far [NAME(g_fpfnDevHlp)]
+    jc near VGDrvOS2IDCService16_InvalidPointer
+    jmp     .finish_data
+.no_data:
+    xor     eax, eax
+.finish_data:
+    push    eax                         ; esp + 08h:    pvData
+    movzx   edx, word [bp + 0ch]
+    push    edx                         ; esp + 04h:    iFunction
+    mov     ecx, [bp + 08h]
+    push    ecx                         ; esp + 00h:    u32Session
+
+    JMP16TO32 VGDrvOS2IDCService16_32
+segment TEXT32
+GLOBALNAME VGDrvOS2IDCService16_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code (don't cleanup the stack).
+    call    NAME(VGDrvOS2IDCService)
+
+    ; switch back the stack.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    JMP32TO16 VGDrvOS2IDCService16_16
+segment CODE16
+GLOBALNAME VGDrvOS2IDCService16_16
+
+VGDrvOS2IDCService16_Done:
+    lea     sp, [bp - 10h]
+    pop     esi
+    pop     edx
+    pop     ecx
+    pop     ds
+    pop     es
+    pop     ebp
+    retf
+
+VGDrvOS2IDCService16_InvalidPointer:
+    mov     ax, VERR_INVALID_POINTER
+    jmp     VGDrvOS2IDCService16_Done
+ENDPROC VGDrvOS2IDCService16
+
+
+;;
+; The 16-bit IDC entry point, register based.
+;
+; This is just a wrapper around VGDrvOS2IDCService16 to simplify
+; calls from 16-bit assembly code.
+;
+; @returns ax: VBox status code; cx: The amount of data returned.
+;
+; @param   u32Session          eax   - The above session handle.
+; @param   iFunction           dl    - The requested function.
+; @param   pvData              es:bx - The input/output data buffer.
+; @param   cbData              cx    - The size of the data buffer.
+;
+GLOBALNAME VGDrvOS2IDCService16Asm
+    push    ebp                         ; bp - 0h
+    mov     ebp, esp
+    push    edx                         ; bp - 4h
+
+    push    cx                          ; cbData
+    push    es
+    xor     dh, dh
+    push    dx
+    push    eax
+    call    NAME(VGDrvOS2IDCService16)
+
+    mov     cx, [es:bx + VBGLREQHDR.cbOut]
+
+    mov     edx, [bp - 4]
+    mov     esp, ebp
+    pop     ebp
+    retf
+ENDPROC VGDrvOS2IDCService16Asm
+
+
+
+;;
+; The 16-bit interrupt service routine.
+;
+; OS/2 saves all registers according to the docs, although it doesn't say whether
+; this includes the 32-bit parts. Since it doesn't cost much to be careful, save
+; everything.
+;
+; @returns  CF=0 if it's our interrupt, CF=1 it it isn't.
+;
+;
+GLOBALNAME vgdrvOS2ISR16
+    push    ebp
+    mov     ebp, esp
+    pushf                               ; bp - 02h
+    cli
+    push    eax                         ; bp - 06h
+    push    edx                         ; bp - 0ah
+    push    ebx                         ; bp - 0eh
+    push    ds                          ; bp - 10h
+    push    es                          ; bp - 12h
+    push    ecx                         ; bp - 16h
+    push    esi                         ; bp - 1ah
+    push    edi                         ; bp - 1eh
+
+    and     sp, 0fff0h                  ; align the stack (16-bytes make GCC extremely happy).
+
+    JMP16TO32 vgdrvOS2ISR16_32
+segment TEXT32
+GLOBALNAME vgdrvOS2ISR16_32
+
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+
+    call    KernThunkStackTo32
+
+    call    NAME(vgdrvOS2ISR)
+    mov     ebx, eax
+
+    call    KernThunkStackTo16
+
+    JMP32TO16 vgdrvOS2ISR16_16
+segment CODE16
+GLOBALNAME vgdrvOS2ISR16_16
+
+    lea     sp, [bp - 1eh]
+    pop     edi
+    pop     esi
+    pop     ecx
+    pop     es
+    pop     ds
+    test    bl, 0ffh
+    jnz     .our
+    pop     ebx
+    pop     edx
+    pop     eax
+    popf
+    pop     ebp
+    stc
+    retf
+
+    ;
+    ; Do EIO.
+    ;
+.our:
+    mov     al, [NAME(g_bInterruptLine)]
+    mov     dl, DevHlp_EOI
+    call far [NAME(g_fpfnDevHlp)]
+
+    pop     ebx
+    pop     edx
+    pop     eax
+    popf
+    pop     ebp
+    clc
+    retf
+ENDPROC vgdrvOS2ISR16
+
+
+
+
+
+
+;
+; The 32-bit text segment.
+;
+segment TEXT32
+;;
+; 32-bit worker for registering the ISR.
+;
+; @returns  0 on success, some non-zero OS/2 error code on failure.
+; @param    bIrq        [ebp + 8]       The IRQ number. (uint8_t)
+;
+GLOBALNAME vgdrvOS2DevHlpSetIRQ
+    push    ebp
+    mov     ebp, esp
+    push    ebx
+    push    ds
+
+    call    KernThunkStackTo16
+
+    movzx   ebx, byte [ebp + 8]         ; load bIrq into BX.
+
+    JMP32TO16 vgdrvOS2DevHlpSetIRQ_16
+segment CODE16
+GLOBALNAME vgdrvOS2DevHlpSetIRQ_16
+
+    mov     ax, DATA16                  ; for g_fpfnDevHlp.
+    mov     ds, ax
+    mov     ax, NAME(vgdrvOS2ISR16)     ; The devhlp assume it's relative to DS.
+    mov     dh, 1                       ; 1 = shared
+    mov     dl, DevHlp_SetIRQ
+    call far [NAME(g_fpfnDevHlp)]
+    jnc     .ok
+    movzx   eax, ax
+    or      eax, eax
+    jnz     .go_back
+    or      eax, 6
+    jmp     .go_back
+.ok:
+    xor     eax, eax
+
+.go_back:
+    JMP16TO32 vgdrvOS2DevHlpSetIRQ_32
+segment TEXT32
+GLOBALNAME vgdrvOS2DevHlpSetIRQ_32
+
+    pop     ds                          ; KernThunkStackTo32 ASSUMES flat DS and ES.
+
+    mov     ebx, eax
+    call    KernThunkStackTo32
+    mov     eax, ebx
+
+    pop     ebx
+    pop     ebp
+    ret
+ENDPROC vgdrvOS2DevHlpSetIRQ
+
+
+
+
+;
+; The 16-bit init code.
+;
+segment CODE16_INIT
+GLOBALNAME g_InitCodeStart
+
+;; The device name for DosOpen.
+g_szDeviceName:
+    db  '\DEV\vboxgst$', 0
+
+; icsdebug can't see where stuff starts otherwise. (kDevTest)
+int3
+int3
+int3
+int3
+int3
+int3
+
+;;
+; The Ring-3 init code.
+;
+BEGINPROC vgdrvOS2InitEntrypointServiceInitReq
+    push    ebp
+    mov     ebp, esp
+    push    es                                      ; bp - 2
+    push    sp                                      ; bp - 4
+    push    -1                                      ; bp - 6: hfOpen
+    push    0                                       ; bp - 8: usAction
+    and     sp, 0fffch
+
+    ; check for the init package.
+    cmp     word [es:bx + PKTHDR.cmd], 0
+    jne near .not_init
+
+    ; check that we found the VMMDev.
+    test    byte [NAME(g_fFoundAdapter)], 1
+    jz near .done_err
+
+    ;
+    ; Copy the data out of the init packet.
+    ;
+    mov     eax, [es:bx + PKTINITIN.fpfnDevHlp]
+    mov     [NAME(g_fpfnDevHlp)], eax
+    mov     edx, [es:bx + PKTINITIN.fpszArgs]
+    mov     [g_fpszArgs], edx
+
+    ;
+    ; Open the first driver, close it, and check status.
+    ;
+
+    ; APIRET _Pascal DosOpen(PSZ pszFname, PHFILE phfOpen, PUSHORT pusAction,
+    ;                        ULONG ulFSize, USHORT usAttr, USHORT fsOpenFlags,
+    ;                        USHORT fsOpenMode, ULONG ulReserved);
+    push    seg g_szDeviceName                      ; pszFname
+    push    g_szDeviceName
+    push    ss                                      ; phfOpen
+    lea     dx, [bp - 6]
+    push    dx
+    push    ss                                      ; pusAction
+    lea     dx, [bp - 8]
+    push    dx
+    push    dword 0                                 ; ulFSize
+    push    0                                       ; usAttr = FILE_NORMAL
+    push    1                                       ; fsOpenFlags = FILE_OPEN
+    push    00040h                                  ; fsOpenMode = OPEN_SHARE_DENYNONE | OPEN_ACCESS_READONLY
+    push    dword 0                                 ; ulReserved
+    call far DOS16OPEN
+
+    push    ax                                      ; Quickly flush any text.
+    call    NAME(vgdrvOS2InitFlushText)
+    pop     ax
+
+    or      ax, ax
+    jnz     .done_err
+
+    ; APIRET  APIENTRY DosClose(HFILE hf);
+    mov     cx, [bp - 6]
+    push    cx
+    call far DOS16CLOSE
+    or      ax, ax
+    jnz     .done_err                               ; This can't happen (I hope).
+
+    ;
+    ; Ok, we're good.
+    ;
+    mov     word [es:bx + PKTHDR.status], 00100h    ; done, ok.
+    mov     byte [es:bx + PKTINITOUT.cUnits], 0
+    mov     word [es:bx + PKTINITOUT.cbCode16], NAME(g_InitCodeStart) wrt CODE16
+    mov     word [es:bx + PKTINITOUT.cbData16], NAME(g_InitDataStart) wrt DATA16
+    mov     dword [es:bx + PKTINITOUT.fpaBPBs], 0
+    jmp     .done
+
+    ;
+    ; Init failure.
+    ;
+.done_err:
+    mov     word [es:bx + PKTHDR.status], 0810fh    ; error, done, init failed.
+    mov     byte [es:bx + PKTINITOUT.cUnits], 0
+    mov     word [es:bx + PKTINITOUT.cbCode16], 0
+    mov     word [es:bx + PKTINITOUT.cbData16], 0
+    mov     dword [es:bx + PKTINITOUT.fpaBPBs], 0
+    jmp     .done
+
+    ;
+    ; Not init, return 'unknown command'.
+    ;
+.not_init:
+    mov     word [es:bx + PKTHDR.status], 08103h    ; error, done, unknown command.
+    jmp     .done
+
+    ;
+    ; Request done.
+    ;
+.done:
+    mov     sp, bp
+    pop     ebp
+    retf
+ENDPROC vgdrvOS2InitEntrypointServiceInitReq
+
+
+;;
+; The Ring-0 init code.
+;
+BEGINPROC vgdrvRing0Init
+    push    es
+    push    esi
+    push    ebp
+    mov     ebp, esp
+    and     sp, 0fffch
+
+    ;
+    ; Thunk the argument string pointer first.
+    ;
+    movzx   esi, word [g_fpszArgs]                  ; offset
+    mov     ax, [g_fpszArgs + 2]                    ; selector
+    mov     dl, DevHlp_VirtToLin
+    call far [NAME(g_fpfnDevHlp)]
+    jc near vgdrvRing0Init_done                     ; eax is non-zero on failure (can't happen)
+    push    eax                                     ; 00h - pszArgs (for vgdrvOS2Init).
+
+    ;
+    ; Do 16-bit init?
+    ;
+
+
+    ;
+    ; Do 32-bit init
+    ;
+    JMP16TO32 vgdrvRing0Init_32
+segment TEXT32
+GLOBALNAME vgdrvRing0Init_32
+
+    ; switch stack to 32-bit.
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     es, ax
+    call    KernThunkStackTo32
+
+    ; call the C code.
+    call    NAME(vgdrvOS2Init)
+
+    ; switch back the stack and reload ds.
+    push    eax
+    call    KernThunkStackTo16
+    pop     eax
+
+    mov     dx, seg NAME(g_fInitialized)
+    mov     ds, dx
+
+    JMP32TO16 vgdrvRing0Init_16
+segment CODE16_INIT
+GLOBALNAME vgdrvRing0Init_16
+
+    ; check the result and set g_fInitialized on success.
+    or      eax, eax
+    jnz     vgdrvRing0Init_done
+    mov     byte [NAME(g_fInitialized)], 1
+
+vgdrvRing0Init_done:
+    mov     sp, bp
+    pop     ebp
+    pop     esi
+    pop     es
+    ret
+ENDPROC vgdrvRing0Init
+
+
+;;
+; Flush any text in the text buffer.
+;
+BEGINPROC vgdrvOS2InitFlushText
+    push    bp
+    mov     bp, sp
+
+    ; Anything in the buffer?
+    mov     ax, [NAME(g_cchInitText)]
+    or      ax, ax
+    jz      .done
+
+%if 1
+    ; Write it to STDOUT.
+    ; APIRET  _Pascal DosWrite(HFILE hf, PVOID pvBuf, USHORT cbBuf, PUSHORT pcbBytesWritten);
+    push    ax                                      ; bp - 2 : cbBytesWritten
+    mov     cx, sp
+    push    1                                       ; STDOUT
+    push    seg NAME(g_szInitText)                  ; pvBuf
+    push    NAME(g_szInitText)
+    push    ax                                      ; cbBuf
+    push    ss                                      ; pcbBytesWritten
+    push    cx
+%if 0 ; wlink generates a non-aliased fixup here which results in 16-bit offset with the flat 32-bit selector.
+    call far DOS16WRITE
+%else
+    ; convert flat pointer to a far pointer using the tiled algorithm.
+    push    ds
+    mov     ax, DATA32 wrt FLAT
+    mov     ds, ax
+    mov     eax, g_pfnDos16Write wrt FLAT
+    movzx   eax, word [eax + 2]                     ; High word of the flat address (in DATA32).
+    shl     ax, 3
+    or      ax, 0007h
+    pop     ds
+    mov     [NAME(g_fpfnDos16Write) + 2], ax        ; Update the selector (in DATA16_INIT).
+    ; do the call
+    call far [NAME(g_fpfnDos16Write)]
+%endif
+
+%else ; alternative workaround for the wlink issue.
+    ; Use the save message devhlp.
+    push    esi
+    push    ebx
+    xor     bx, bx
+    mov     si, NAME(g_MsgTab)
+    mov     dx, seg NAME(g_MsgTab)
+    mov     ds, dx
+    mov     dl, DevHlp_SAVE_MESSAGE
+    call far [NAME(g_fpfnDevHlp)]
+    pop     ebx
+    pop     esi
+%endif
+
+    ; Empty the buffer.
+    mov     word [NAME(g_cchInitText)], 0
+    mov     byte [NAME(g_szInitText)], 0
+
+.done:
+    mov     sp, bp
+    pop     bp
+    ret
+ENDPROC vgdrvOS2InitFlushText
+
+
+;; The device name for DosOpen.
+g_szOemHlpDevName:
+    db  '\DEV\OEMHLP$', 0
+
+
+;;
+; Talks to OEMHLP$ about finding the VMMDev PCI adapter.
+;
+; On success g_fFoundAdapter is set to 1, and g_cbMMIO,
+; g_PhysMMIOBase and g_IOPortBase are initialized with
+; the PCI data.
+;
+; @returns  0 on success, non-zero on failure. (eax)
+;
+; @remark   ASSUMES DS:DATA16.
+; @uses     nothing.
+;
+BEGINPROC vgdrvFindAdapter
+    push    ebx
+    push    ecx
+    push    edx
+    push    esi
+    push    edi
+    push    ebp
+    mov     ebp, esp
+    push    -1                                      ; bp - 2: hfOpen
+%define hfOpen      bp - 2
+    push    0                                       ; bp - 4: usAction
+%define usAction    bp - 4
+    sub     sp, 20h                                 ; bp - 44: 32 byte parameter buffer.
+%define abParm      bp - 24h
+    sub     sp, 40h                                 ; bp - c4: 32 byte data buffer.
+%define abData      bp - 44h
+
+;; VBox stuff
+%define VBOX_PCI_VENDORID       080eeh
+%define VMMDEV_DEVICEID         0cafeh
+
+;; OEMHLP$ stuff.
+%define IOCTL_OEMHLP            80h
+%define OEMHLP_PCI              0bh
+%define PCI_FIND_DEVICE         1
+%define PCI_READ_CONFIG         3
+
+;; PCI stuff
+%define PCI_INTERRUPT_LINE      03ch                ;;< 8-bit RW - Interrupt line.
+%define PCI_BASE_ADDRESS_0      010h                ;;< 32-bit RW */
+%define PCI_BASE_ADDRESS_1      014h                ;;< 32-bit RW */
+
+
+%macro CallIOCtl 2
+    ; APIRET _Pascal DosDevIOCtl2(PVOID pData, USHORT cbData, PVOID pParm,
+    ;                             USHORT cbParm, USHORT usFun, USHORT usCategory,
+    ;                             HFILE hDev);
+    push    ss                                      ; pData
+    lea     dx, [abData]
+    push    dx
+    push    %2                                      ; cbData
+
+    push    ss                                      ; pParm
+    lea     dx, [abParm]
+    push    dx
+    push    %1                                      ; cbParm
+    push    OEMHLP_PCI                              ; usFun
+    push    IOCTL_OEMHLP                            ; usCategory
+
+    mov     ax, [hfOpen]                            ; hDev
+    push    ax
+    call far DOS16DEVIOCTL2
+
+    ; check for error.
+    test    ax, ax
+    jnz near .done_err_close
+    cmp     [abData + 0], byte 0
+    jne near .done_err_close
+%endmacro
+
+
+    ;
+    ; Open the OEMHLP$ driver.
+    ;
+
+    ; APIRET _Pascal DosOpen(PSZ pszFname, PHFILE phfOpen, PUSHORT pusAction,
+    ;                        ULONG ulFSize, USHORT usAttr, USHORT fsOpenFlags,
+    ;                        USHORT fsOpenMode, ULONG ulReserved);
+    mov     di, '0'
+    push    seg g_szOemHlpDevName                   ; pszFname
+    push    g_szOemHlpDevName
+    push    ss                                      ; phfOpen
+    lea     dx, [hfOpen]
+    push    dx
+    push    ss                                      ; pusAction
+    lea     dx, [usAction]
+    push    dx
+    push    dword 0                                 ; ulFSize
+    push    0                                       ; usAttr = FILE_NORMAL
+    push    1                                       ; fsOpenFlags = FILE_OPEN
+    push    00040h                                  ; fsOpenMode = OPEN_SHARE_DENYNONE | OPEN_ACCESS_READONLY
+    push    dword 0                                 ; ulReserved
+    call far DOS16OPEN
+    or      ax, ax
+    jnz near .done
+
+
+    ;
+    ; Send a PCI_FIND_DEVICE request.
+    ;
+
+    ; Initialize the parameter packet.
+    mov     [abParm + 0], byte PCI_FIND_DEVICE      ; 0 - db - SubFunction Number
+    mov     [abParm + 1], word VMMDEV_DEVICEID      ; 1 - dw - Device ID
+    mov     [abParm + 3], word VBOX_PCI_VENDORID    ; 3 - dw - Vendor ID
+    mov     [abParm + 5], byte 0                    ; 5 - db - (Device) Index
+
+    ; Zero padd the data packet.
+    mov     [abData + 0], dword 0
+
+    mov     di, '1'
+    CallIOCtl 6, 3
+
+    mov     al, [abData + 1]                        ; 1 - db - Bus Number.
+    mov     [NAME(g_bPciBusNo)], al
+    mov     al, [abData + 2]                        ; 2 - db - DevFunc Number.
+    mov     [NAME(g_bPciDevFunNo)], al
+
+    ;
+    ; Read the interrupt register (byte).
+    ;
+    mov     di, '2'
+    mov     ax, PCI_INTERRUPT_LINE | 0100h
+    call .NestedReadReg
+    mov     [NAME(g_bInterruptLine)], al
+
+    ;
+    ; Read the first base address (dword), this shall must be in I/O space.
+    ;
+    mov     di, '3'
+    mov     ax, PCI_BASE_ADDRESS_0 | 0400h
+    call .NestedReadReg
+    mov     di, '4'
+    test    al, 1h                                  ; Test that it's an I/O space address.
+    jz      .done_err_close
+    mov     di, '5'
+    test    eax, 0ffff0002h                         ; These shall all be 0 according to the specs.
+    jnz     .done_err_close
+    and     ax, 0fffeh
+    mov     [NAME(g_IOPortBase)], ax
+
+    ;
+    ; Read the second base address (dword), this shall be in memory space if present.
+    ;
+    mov     di, '6'
+    mov     ax, PCI_BASE_ADDRESS_1 | 0400h
+    call .NestedReadReg
+    mov     di, '7'
+    test    al, 1h                                  ; Test that it's a memory space address.
+    jnz     .done_err_close
+    and     eax, 0fffffff0h
+    mov     [NAME(g_PhysMMIOBase)], eax
+
+    ;or      eax, eax
+    ;jz      .done_success                             ; No memory region.
+    ;; @todo If there is a simple way of determining the size do that, if
+    ;        not we can easily handle it the code that does the actual mapping.
+
+
+    ;
+    ; Ok, we're good!
+    ;
+.done_success:
+    or      [NAME(g_fFoundAdapter)], byte 1
+    jmp     .done_close
+
+    ;
+    ; Close the OEMHLP$ driver.
+    ;
+.done_err_close:
+    or      ax, 80h
+.done_close:
+    ; APIRET  APIENTRY DosClose(HFILE hf);
+    push    ax                                      ; Save result
+    mov     cx, [hfOpen]
+    push    cx
+    call far DOS16CLOSE
+    or      ax, ax
+    jnz     .bitch                                  ; This can't happen (I hope).
+    pop     ax
+    or      ax, ax
+    jnz     .bitch
+
+    ;
+    ; Return to vgdrvOS2EP_Init.
+    ;
+.done:
+    mov     esp, ebp
+    pop     ebp
+    pop     edi
+    pop     esi
+    pop     edx
+    pop     ecx
+    pop     ebx
+    ret
+
+
+    ;
+    ; Puts the reason for failure in message buffer.
+    ; The caller will flush this.
+    ;
+.bitch:
+    push    es
+
+    mov     ax, ds
+    mov     es, ax
+    mov     ax, di                                  ; save the reason.
+    mov     di, NAME(g_szInitText)
+    add     di, [NAME(g_cchInitText)]
+
+    mov     si, g_achLoadFailureMsg1
+    mov     cx, g_cchLoadFailureMsg1
+    rep movsb
+
+    stosb
+
+    mov     si, g_achLoadFailureMsg2
+    mov     cx, g_cchLoadFailureMsg2
+    rep movsb
+
+    mov     [di], byte 0
+    sub     di, NAME(g_szInitText)
+    mov     [NAME(g_cchInitText)], di
+
+    pop     es
+    jmp     .done
+
+
+    ;
+    ; Nested function which reads a PCI config register.
+    ; (This operates on the vgdrvFindAdapter stack frame.)
+    ;
+    ; Input:
+    ;   al - register to read
+    ;   ah - register size.
+    ;
+    ; Output:
+    ;   eax - the value.
+    ;
+    ; Uses:
+    ;   dx
+    ;
+.NestedReadReg:
+    ; Fill in the request packet.
+    mov     [abParm + 0], byte PCI_READ_CONFIG      ; 0 - db - SubFunction Number
+    mov     dl, [NAME(g_bPciBusNo)]
+    mov     [abParm + 1], dl                        ; 1 - db - Bus Number
+    mov     dl, [NAME(g_bPciDevFunNo)]
+    mov     [abParm + 2], dl                        ; 2 - db - DevFunc Number
+    mov     [abParm + 3], al                        ; 3 - db - Configuration Register
+    mov     [abParm + 4], ah                        ; 4 - db - (Register) Size
+
+    ; Pad the data packet.
+    mov     [abData + 0], dword 0
+    mov     [abData + 4], dword 0
+
+    CallIOCtl 5, 5
+
+    mov     eax, [abData + 1]                       ; 1 - dd - Data
+
+    ret
+
+ENDPROC vgdrvFindAdapter
+
+
+
+;;
+; This must be present
+segment DATA32
+g_pfnDos16Write:
+    dd  DOS16WRITE  ; flat
+