On 05/13/14 14:58, Jaeyong Yoo wrote:
> Hello qemu!
>
>
>
> I am currently writing a vga device emulator and need to debug vga-bios.
>
> What I want is to set break-point on the entry of vga-bios and for this,
>
> I'm reading qemu source around pci device and rom-related memory regions
>
> to find out where should I set break point. And, sadly, got stuck.
>
>
>
> Could you give me any advice about the memory-mapped address of vga-rom or
>
> any pointers?
Some.
The vgabios binary is loaded from the file identified by the "romfile"
property of the VGA card that you select. For example,
-device qxl-vga,romfile=...
or
-vga qxl \
-global qxl-vga.romfile=...
Of course the property has a default value for each VGA card. See the
k->romfile = ...
assignments in:
- cirrus_vga_class_init() -- vgabios-cirrus.bin
- qxl_primary_class_init() -- vgabios-qxl.bin
- vga_class_init() -- vgabios-stdvga.bin
I think the oprom is loaded in
pci_qdev_init() [hw/pci/pci.c]
pci_add_option_rom()
The vgabios oprom is shadowed from ROM (pci address space) to RAM by the
SeaBIOS initialization code, and then POSTed:
handle_post() [src/post.c]
make_bios_writable() [src/fw/shadow.c]
make_bios_writable_intel()
__make_bios_writable_intel() -- shadows vgabios in C segment too
dopost() [src/post.c]
maininit()
vgarom_setup() [src/optionroms.c]
init_pcirom()
init_optionrom()
callrom()
__callrom()
_rom_header_entry [vgasrc/vgaentry.S]
vga_post() [vgasrc/vgainit.c]
You can instrument vga_post() in the SeaBIOS source [vgasrc/vgainit.c],
rebuild the vgabios binary, and load this binary with the video card's
romfile=... property on the qemu command line.
Laszlo
Laszlo
