[Plex86-devel] plex86 physical page out of bound error

[philippe lhardy]

Hi,

I am facing a bug and can't tun plex86 that stop on :
bochs: CMOS: write reg 14h: value = 04h
::plex86 panic: 
::emulate:1 default case of 3

Fatal monitor error caused Panic
eax:0x148000
ebx:0x7c00
ecx:0x140001
edx:0xf000
ebp:0x0
esi:0x0
edi:0x500
esp:0xc
eflags:0x7046
6 PF
4 ZF
111000001000110
niioditsz a p c
too     f f f f
 pp
 ll
 3
eip:0xf00ad0
cs:s=0xff53, dl=0xf530ffff, dh=0x9b0f, valid=1
ss:s=0x0, dl=0xffff, dh=0x9300, valid=1
ds:s=0xff53, dl=0xf530ffff, dh=0x930f, valid=1
es:s=0x0, dl=0xffff, dh=0x9300, valid=1
fs:s=0x0, dl=0xffff, dh=0x9300, valid=1
gs:s=0x0, dl=0xffff, dh=0x9300, valid=1
ldtr:s=0x0, dl=0x0, dh=0x0, valid=0
tr:s=0x0, dl=0x0, dh=0x0, valid=0
gdtr:base=0x0, limit=0x0
idtr:base=0x0, limit=0x3ff
dr0:0x0
dr1:0x0
dr2:0x0
dr3:0x0
dr6:0xffff0ff0
dr7:0x400
tr3:0x0
tr4:0x0
tr5:0x0
tr6:0x0
tr7:0x0
cr0:0x60000032
          ..00110010
              netemp
              etsmpe
      0110..
      pcn
      gdw
no paging
cache disable
not write through
protection enable = 0
extension type=1

cr1:0x0
cr2:0x0
cr3:0x0
cr4:0x0
inhibit_mask:0
Stack dump:
Current instruction:
 FF53.00F00AD0  7F45                     jg      FF53:0B17

i tried with different configurations ( see # )

####################################################################
# This is an example plex86 configuration file
####################################################################


####################################################################
# Memory settings
####################################################################

# number of megabytes for vm
memory = 16


####################################################################
# Plugins
####################################################################

plugin = ./plugins/bochs/plugin-bochs.so
plugin = ./plugins/bochs/iodev/cmos.so
plugin = ./plugins/bochs/iodev/dma.so
plugin = ./plugins/bochs/iodev/system.so
plugin = ./plugins/bochs/iodev/vga.so
plugin = ./plugins/bochs/iodev/serial.so
plugin = ./plugins/bochs/iodev/parallel.so
plugin = ./plugins/bochs/iodev/keyboard.so
plugin = ./plugins/bochs/iodev/floppy.so
plugin = ./plugins/bochs/iodev/harddrv.so

bochs-opt boot: c

#bochs-opt diskc: file="../../10M.vga", cyl=306, heads=4, spt=17
bochs-opt diskc: file="../../10M.vga", cyl=20, heads=16, spt=63
#bochs-opt floppya: 1_44=../../tomsrtbt-2.0.103/tomsrtbt.raw, status=inserted

bochs-opt floppya: 1_44=/reiser2/compilations/tomsrtbt-1.7.361/tomsrtbt.raw, 
status=inserted

bochs-opt keyboard_serial_delay: 200

bochs-opt floppy_command_delay: 500

bochs-opt vga_update_interval: 200000

bochs-opt mouse: enabled=0

bochs-opt private_colormap: enabled=0

bochs-opt i440fxsupport: enabled=0

bochs-opt newharddrivesupport: enabled=0

bochs-opt ips: 1000000

#bochs-opt time0: 938581955
#bochs-init

CMOSChecksum

# The system BIOS
load-rom: file=../bios/BIOS-plex86-current, address=0xf0000
#load-rom: file=../bios/BIOS-plex86-2000_1228a, address=0xf0000
#load-rom: file=../bios/BIOS-plex86-2000_0817a, address=0xf0000
#load-rom: file=../bios/BIOS-plex86-2000_0802a, address=0xf0000

# The VGA BIOS
#load-rom: file=../bios/VGABIOS-elpin-2.40, address=0xc0000
#load-rom: file=../bios/VGABIOS-lgpl-latest.debug.bin, address=0xc0000


####################################################################
# Debugging settings
####################################################################

# syntax for disassembly
#db_syntax = at&t
db_syntax = intel


####################################################################
# VM tweaks            
####################################################################
  
# Maximum depth that the scan-before-execute code will try
# to recursively prescan code in the current code page, by
# following intra-page branches.
prescan: depth = 3, ring3 = on



####################################################################
# end of config file
####################################################################

----------------------------------------------------------------------

It seems related to consuming of memory vecause error occurs at diferent point 
if i allocate more memory :

memory = 8 =>  FF53.00700AD0  7F45                     jg      FF53:0B17
memory = 4 =>  FF53.00300AD0  7F45                     jg      FF53:0B17

I think i occurs in BIOS, perhaps even it is the initial memory check that 
fails.
We are not in protected mode and memory is not paged.
perhaps the on board memory returned is false and then the whole memory check 
fail....

I would be interested by any hint how to debug that step by step or by adding 
traces or whatever...