Re: [kvm-unit-tests PATCH 1/2] s390x: smp: Use full PSW to bringup new cpu

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

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On 12/11/19 1:31 PM, David Hildenbrand wrote:
> On 11.12.19 12:59, Janosch Frank wrote:
>> Up to now we ignored the psw mask and only used the psw address when
>> bringing up a new cpu. For DAT we need to also load the mask, so let's
>> do that.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>  lib/s390x/smp.c  | 2 ++
>>  s390x/cstart64.S | 2 +-
>>  2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/s390x/smp.c b/lib/s390x/smp.c
>> index f57f420..e17751a 100644
>> --- a/lib/s390x/smp.c
>> +++ b/lib/s390x/smp.c
>> @@ -185,6 +185,8 @@ int smp_cpu_setup(uint16_t addr, struct psw psw)
>>  	cpu->stack = (uint64_t *)alloc_pages(2);
>>  
>>  	/* Start without DAT and any other mask bits. */
>> +	cpu->lowcore->sw_int_psw.mask = psw.mask;
>> +	cpu->lowcore->sw_int_psw.addr = psw.addr;
>>  	cpu->lowcore->sw_int_grs[14] = psw.addr;
> 
> Not looking at the code (sorry :D ), do we still need this then? (you
> drop the br bewlo)

r14 is the return address, saving/initialising it doesn't sound like a
bad idea to me. If we ever have stack traces, it might show up, or won't it?

> 
>>  	cpu->lowcore->sw_int_grs[15] = (uint64_t)cpu->stack + (PAGE_SIZE * 4);
>>  	lc->restart_new_psw.mask = 0x0000000180000000UL;
>> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
>> index 86dd4c4..e6a6bdb 100644
>> --- a/s390x/cstart64.S
>> +++ b/s390x/cstart64.S
>> @@ -159,7 +159,7 @@ smp_cpu_setup_state:
>>  	xgr	%r1, %r1
>>  	lmg     %r0, %r15, GEN_LC_SW_INT_GRS
>>  	lctlg   %c0, %c0, GEN_LC_SW_INT_CRS
>> -	br	%r14
>> +	lpswe	GEN_LC_SW_INT_PSW
>>  
>>  pgm_int:
>>  	SAVE_REGS
>>
> 
> 



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