Rebooting from loader causes a "fault" in VMware Workstation

[Andriy Gapon]

on 23/04/2013 17:36 Dimitry Andric said the following:
> I have tried to ascertain it actually arrives at this code when
> rebooting from the loader, but it does not seem to ever make it there,
> at least not to the jump to f000:fff0.  Maybe VMware intercepts the
> switching back to real mode in the previous part, and dies on that, I am
> not sure.  It is of course rather tricky to print off any debug messages
> at that point. :-)

For the inquisitive minds here how last instructions (and CPU state) look
according to qemu log:

IN:
0x000000000000a030:  xor    %eax,%eax
0x000000000000a032:  int    $0x30

----------------
IN:
0x00000000000093e0:  cmp    $0x1,%eax
0x00000000000093e3:  jne    0x93ff

----------------
IN:
0x00000000000093ff:  orb    $0x1,%ss:0x9007
0x0000000000009407:  jmp    0x90d2

----------------
IN:
0x00000000000090d2:  cli
0x00000000000090d3:  mov    $0x1800,%esp
0x00000000000090d8:  mov    %cr0,%eax
0x00000000000090db:  and    $0x7fffffff,%eax
0x00000000000090e0:  mov    %eax,%cr0

----------------
IN:
0x00000000000090e3:  xor    %ecx,%ecx
0x00000000000090e5:  mov    %ecx,%cr3

----------------
IN:
0x00000000000090e8:  lgdtl  0x95d0
0x00000000000090ef:  ljmpw  $0x18,$0x90f5

Triple fault
CPU Reset (CPU 0)
ESI=0004503c EDI=3fe50968 EBP=00094a80 ESP=00001800
EIP=000090ef EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0033 0000a000 ffffffff 00cff300 DPL=3 DS   [-WA]
CS =0008 00000000 ffffffff 00cf9a00 DPL=0 CS32 [-R-]
SS =0010 00000000 ffffffff 00cf9300 DPL=0 DS   [-WA]
DS =0033 0000a000 ffffffff 00cff300 DPL=3 DS   [-WA]
FS =0033 0000a000 ffffffff 00cff300 DPL=3 DS   [-WA]
GS =0033 0000a000 ffffffff 00cff300 DPL=3 DS   [-WA]
LDT=0000 00000000 0000ffff 00008200 DPL=0 LDT
TR =0038 00005f98 00002067 00008900 DPL=0 TSS32-avl
GDT=     ff85c789 00000000
IDT=     00005e00 00000197
CR0=00000011 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
CCS=00000001 CCD=00000000 CCO=LOGICL
EFER=0000000000000000

-- 
Andriy Gapon