Custom module VBoxVgaBiosAlternative

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evgeny8788
Posts: 4
Joined: 14. Sep 2023, 17:26

Custom module VBoxVgaBiosAlternative

Post by evgeny8788 »

Hello all

Im try compile virtualbox myself. my need is pretty simple. i need modify VBoxVgaBiosAlternative.asm files

can any expert here can explain how these 3 files are generated ?

Folder Location: src\VBox\Devices\Graphics\BIOS

VBoxVgaBiosAlternative286.asm
VBoxVgaBiosAlternative386.asm
VBoxVgaBiosAlternative8086.asm

My goal is modify vga BIOS display adapter description.

'VirtualBox VESA BIOS'
'Oracle Corporation'
'Oracle VM VirtualBox VBE Adapter'
'Oracle VM VirtualBox Version 6.0.23'
'VirtualBox VBE Display Adapter enabled'
'No VirtualBox VBE support available!'

what correct way i can modify these data, since this Assembler Source (.asm) cannot be edited direct. any help is welcome. Thanks in advance
mpack
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Posts: 39156
Joined: 4. Sep 2008, 17:09
Primary OS: MS Windows 10
VBox Version: PUEL
Guest OSses: Mostly XP

Re: Custom module VBoxVgaBiosAlternative

Post by mpack »

I can't help on your primary problem, but if your goal is to hide the fact that it's a VM then this will not do it. E.g. the VT-x enabled flag is visible to the guest OS, and there are many other giveaways.
evgeny8788
Posts: 4
Joined: 14. Sep 2023, 17:26

Re: Custom module VBoxVgaBiosAlternative

Post by evgeny8788 »

You correct, this a part of my final goal, but its a experimental project.
i need remove these signatures oracle on VGA BIOS module. its just a visual tweek on display adapter inside Guest VMs
All other module is already Patched, only this module missing :(
Last edited by evgeny8788 on 14. Sep 2023, 17:58, edited 1 time in total.
evgeny8788
Posts: 4
Joined: 14. Sep 2023, 17:26

Re: Custom module VBoxVgaBiosAlternative

Post by evgeny8788 »

mpack wrote: 14. Sep 2023, 17:48 I can't help on your primary problem, but if your goal is to hide the fact that it's a VM then this will not do it. E.g. the VT-x enabled flag is visible to the guest OS, and there are many other giveaways.
Are you familiar with GCC ? how oracle devs generate this assembly source file "VBoxVgaBiosAlternative386.asm" ?
fth0
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Re: Custom module VBoxVgaBiosAlternative

Post by fth0 »

AFAIU, using an old Open Watcom compiler is the key. Take a look at src/VBox/Devices/Graphics/BIOS/Makefile.kmk.
evgeny8788
Posts: 4
Joined: 14. Sep 2023, 17:26

Re: Custom module VBoxVgaBiosAlternative

Post by evgeny8788 »

fth0 wrote: 15. Sep 2023, 01:50 AFAIU, using an old Open Watcom compiler is the key. Take a look at src/VBox/Devices/Graphics/BIOS/Makefile.kmk.
Thankssssssssssssssss mi king

If it not mess up you, can you give me more details how compile it ? just put C source file then output is the VBoxVgaBiosAlternative.asm files ?
fth0
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Re: Custom module VBoxVgaBiosAlternative

Post by fth0 »

Sorry, but I do not intend to explain the Makefile concepts. I just wanted to point you to a suitable starting point for self-study (although that starting point (the Makefile.kmk file) should have been obvious by itself). And we're talking about assembler source files here, not C.
evgeny8788
Posts: 4
Joined: 14. Sep 2023, 17:26

Re: Custom module VBoxVgaBiosAlternative

Post by evgeny8788 »

fth0 wrote: 15. Sep 2023, 13:02 Sorry, but I do not intend to explain the Makefile concepts. I just wanted to point you to a suitable starting point for self-study (although that starting point (the Makefile.kmk file) should have been obvious by itself). And we're talking about assembler source files here, not C.
Thank you

The point you told me, i get output source file VBoxVgaBiosAlternative.asm

My goal is get this assembly source VBoxVgaBiosAlternative.asm source. I need generate new ones

More reference to contribute with this topic: https://www.virtualbox.org/ticket/12011
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