Re: Does kvm_pr work on G5 mac with host kernel 6.12.xx ?

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Le 15/06/2026 à 15:33, BALATON Zoltan a écrit :
> On Mon, 15 Jun 2026, Andrew Randrianasulu wrote:
>> I also tried to see "info registers" as you showed in another email from
>> 2021 where you tried to use kvm-pr on qemu-emulated G5 and it showed
>>
>> info registers
>>                NIP 0000000000000700   LR 0000000000000000 CTR
>> 0000000000000000 XER 0000000000000000 CPU#0
>> MSR 8000000000000000 HID0 0000000060000000  HF 8000000000000000 iidx 3 
>> didx
>> 3                      TB 00000000 00000000 DECR 0
>>                                              GPR00 0000000000000000
>> 0000000000000000 0000000000000000 0000000000000000
>> GPR04 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                        GPR08 0000000000000000 0000000000000000
>> 0000000000000000 0000000000000000                          GPR12
>> 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>> GPR16 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                        GPR20 0000000000000000 0000000000000000
>> 0000000000000000 0000000000000000                          GPR24
>> 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                  GPR28 0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000
>> CR 00000000  [ -  -  -  -  -  -  -  -  ]             RES ffffffffffffffff
>>                        FPR00 0000000000000000 0000000000000000
>> 0000000000000000 0000000000000000                          FPR04
>> 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                  FPR08 0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000
>> FPR12 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                        FPR16 0000000000000000 0000000000000000
>> 0000000000000000 0000000000000000                          FPR20
>> 0000000000000000 0000000000000000 0000000000000000 0000000000000000
>>                  FPR24 0000000000000000 0000000000000000 0000000000000000
>> 0000000000000000                          FPR28 0000000000000000
>> 0000000000000000 0000000000000000 0000000000000000
>> FPSCR 0000000000000000
>>                        SRR0 0000000000000100  SRR1 8000000000080000    
>> PVR
>> 00000000003c0301 VRSAVE 0000000000000000      SPRG0 0000000000000000 
>> SPRG1
>> 0000000000000000  SPRG2 0000000000000000  SPRG3 0000000000000000      
>> SPRG4
>> 0000000000000000 SPRG5 0000000000000000  SPRG6 0000000000000000  SPRG7
>> 0000000000000000
>> SDR1 0000000000000000   DAR 0000000000000000  DSISR 0000000000000000
>>
>> (qemu) q
>>
>> not sure if instruction pointer moved or not ...
>>
>> looking at some scroll buffer in Termux (I ssh into powermac ) it was at
>> 700 all 3 times I typed "info registers" into qemu monitor.
>>
>> but this debug msg
>>
>> [154992.595845] Couldn't emulate instruction 0x00000000 (op 0 xop 0)
>> [154992.595859] kvmppc_exit_pr_progint: emulation at 100 failed 
>> (00000000)
>>
>>
>> fills logs FAST!
> 
> NIP=0x700 is illegal instruction exception due to trying to execute 0 
> opcode at 0x100 which is the reset vector but shouldn't it try to start 
> at 0xfff00100? Maybe there's some issue with setting up KVM correctly?

On powerpc32 it is 0x100 or 0xfff00100 based on whether bit IP 
(Interrupt Prefix) is 0 or 1 in MSR register.

On powerpc64 MSR[IP] doesn't exist.

Christophe

> You can trace what is executed in TCG with -d in_asm but that does not 
> work for KVM as it's a TCG debug option. I don't know how to trace 
> execution with KVM but probably there are some trace points for that. 
> Maybe you get some info with -trace enable="kvm*" but I don't know how 
> to understand that output.
> 
> Regards,
> BALATON Zoltan
>