Re: [PATCH 1/3] powerpc/xmon: Check for HV mode when dumping XIVE info from OPAL

["Cédric Le Goater" <clg@kaod.org>]

On 15/08/2019 09:30, Jordan Niethe wrote:
> On Wed, 2019-08-14 at 17:47 +0200, Cédric Le Goater wrote:
>> Currently, the xmon 'dx' command calls OPAL to dump the XIVE state in
>> the OPAL logs and also outputs some of the fields of the internal
>> XIVE
>> structures in Linux. The OPAL calls can only be done on baremetal
>> (PowerNV) and they crash a pseries machine. Fix by checking the
>> hypervisor feature of the CPU.
>>
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> ---
>>  arch/powerpc/xmon/xmon.c | 17 ++++++++++-------
>>  1 file changed, 10 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
>> index 14e56c25879f..25d4adccf750 100644
>> --- a/arch/powerpc/xmon/xmon.c
>> +++ b/arch/powerpc/xmon/xmon.c
>> @@ -2534,13 +2534,16 @@ static void dump_pacas(void)
>>  static void dump_one_xive(int cpu)
>>  {
>>  	unsigned int hwid = get_hard_smp_processor_id(cpu);
>> -
>> -	opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
>> -	opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
>> -	opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
>> -	opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
>> -	opal_xive_dump(XIVE_DUMP_VP, hwid);
>> -	opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
>> +	bool hv = cpu_has_feature(CPU_FTR_HVMODE);
>> +
>> +	if (hv) {
>> +		opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
>> +		opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
>> +		opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
>> +		opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
>> +		opal_xive_dump(XIVE_DUMP_VP, hwid);
>> +		opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
>> +	}
>>  
>>  	if (setjmp(bus_error_jmp) != 0) {
>>  		catch_memory_errors = 0;
> dump_one_xive() / other xive functions are guarded by #ifdef
> CONFIG_PPC_POWERNV in xmon.c aren't they? With this series would it be
> that these guards can be removed?

One could compile without CONFIG_PPC_POWERNV but we would still want 
these commands to be available for pseries. I missed that.

I think we should move the opal_xive_dump calls to some other command, 
dxo for 'dump_xive_opal' may be, as they only output in the OPAL logs.

This needs some rework.

Thanks,

C.