Re: [Qemu-devel] [Bug] qemu-system-ppc: "invalid/unsupported opcode" during debug session

[Aurelien Jarno]

On Tue, Dec 29, 2009 at 04:09:17PM +0100, Stefan Weil wrote:
> Test environment:
> 
> * ppc-softmmu/qemu-system-ppc running on x86_64 host
> * emulated ppc is running debian lenny
> 
> 
> 
> While debugging on the emulated ppc (each time when
> a shared library is loaded after "r" command?),
> qemu-system-ppc prints this error message:
> 
> invalid/unsupported opcode: 00 - 00 - 00 (00000000) 4800fa44 1
> 
> 
> 
> If logging is enabled, the error message goes to qemu.log:
> 
> IN:
> 0xc0013488:  nop
> 0xc001348c:  rlwinm  r3,r3,0,0,19
> 0xc0013490:  li      r4,128
> 0xc0013494:  mtctr   r4
> 0xc0013498:  mr      r6,r3
> 0xc001349c:  dcbst   r0,r3
> 
> invalid/unsupported opcode: 00 - 00 - 00 (00000000) 4800fa44 1
> IN:
> 0x4800fa40:  twge    r2,r2
> 0x4800fa44:  .long 0x0
> 

The problem is that QEMU doesn't stop the decoding of instructions when
it encounters a trap instruction. We should probably either end the TB 
in that case, or avoid printing "invalid/unsupported opcode", as this
instruction will actually never been executed.
 

-- 
Aurelien Jarno                          GPG: 1024D/F1BCDB73
address@hidden                 http://www.aurel32.net