Re: [Qemu-devel] Sparc sun4v machine currently broken?

[Artyom Tarasenko]

On Fri, Feb 10, 2017 at 6:29 PM, Thomas Huth <address@hidden> wrote:
> On 10.02.2017 14:49, Thomas Huth wrote:
>>  Hi,
>>
>> is it just me, or could it be that the sun4v machine is currently broken?
>> I get the following error when I try to run QEMU with this machine:
>>
>> qemu-system-sparc64 -nographic -M sun4v
>> qemu: fatal: Trap 0x0010 while trap level (6) >= MAXTL (6), Error state
>> pc: 0000000000000200  npc: 0000000000000204
>> %g0-3: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %g4-7: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %o0-3: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %o4-7: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %l0-3: 0000000007f00000 000001ff00000000 000001fff0080000 0000000000000000
>> %l4-7: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %i0-3: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %i4-7: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f00:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f08:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f16:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f24:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f32:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f40:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f48:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> %f56:  0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> pstate: 00000014 ccr: 44 (icc: -Z-- xcc: -Z--) asi: 00 tl: 6 pil: 0 gl: 8
>> tbr: 0000000000000000 hpstate: 0000000000000004 htba: 0000000000000000
>> cansave: 6 canrestore: 0 otherwin: 0 wstate: 0 cleanwin: 6 cwp: 7
>> fsr: 0000000000000000 y: 0000000000000000 fprs: 0000000000000000
>>
>> Aborted (core dumped)
>>
>> It works for when I use an older version of QEMU (version 2.7)...
>
> FWIW, it's also still working when I use QEMU 2.8, so this must be a
> recent regression...

Oh. This is surprising. Sun4v practically wasn't implemented before my
niagara series.
So, OpenBIOS worked because -M sun4v was like -M sun4u with some sun4v
instructions.
Now sun4v is closer to a real sun4v - it has sun4v MMU, so OpenBIOS is
not compatible with it anymore.
The proper fix would be adding sun4v support to OpenBIOS, but it may
take some time.


-- 
Regards,
Artyom Tarasenko

SPARC and PPC PReP under qemu blog: http://tyom.blogspot.com/search/label/qemu