Re: [kvm-unit-tests PATCH 2/2] s390x: smp: Setup CRs from cpu 0

[Janosch Frank <frankja@linux.ibm.com>]

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On 12/11/19 1:32 PM, David Hildenbrand wrote:
> On 11.12.19 12:59, Janosch Frank wrote:
>> Grab the CRs (currently only 0, 1, 7, 13) from cpu 0, so we can
>> bringup the new cpu in DAT mode or set other control options.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  lib/s390x/smp.c  | 5 ++++-
>>  s390x/cstart64.S | 2 +-
>>  2 files changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
>> index e17751a..4dfe7c6 100644
>> --- a/lib/s390x/smp.c
>> +++ b/lib/s390x/smp.c
>> @@ -191,7 +191,10 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
>>  	cpu->lowcore->sw_int_grs[15] = (uint64_t)cpu->stack + (PAGE_SIZE * 4);
>>  	lc->restart_new_psw.mask = 0x0000000180000000UL;
>>  	lc->restart_new_psw.addr = (uint64_t)smp_cpu_setup_state;
>> -	lc->sw_int_crs[0] = 0x0000000000040000UL;
>> +	lc->sw_int_crs[0] = stctg(0);
>> +	lc->sw_int_crs[1] = stctg(1);
>> +	lc->sw_int_crs[7] = stctg(7);
>> +	lc->sw_int_crs[13] = stctg(13);
> 
> Wouldn't it be better to also be able to specify the CRs explicitly here?
> 

Yes, but currently there are no users for something like that and it
would mean that we might need to add more code to support it.

As I said in the cover letter, this is a good first step to allow DAT on
additional cpus without any real setup needed in a test. Later we could
add a function to specify the CRs explicitly.


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