Re: [kvm-unit-tests PATCH v2 4/6] s390x: Add initial smp code

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

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On 9/9/19 5:37 PM, Thomas Huth wrote:
> On 05/09/2019 12.39, Janosch Frank wrote:
>> Let's add a rudimentary SMP library, which will scan for cpus and has
>> helper functions that manage the cpu state.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
> [...]
>> +/*Expected to be called from boot cpu */
>> +extern uint64_t *stackptr;
>> +void smp_setup(void)
>> +{
>> +	int i = 0;
>> +	unsigned short cpu0_addr = stap();
>> +	struct ReadCpuInfo *info = (void *)cpu_info_buffer;
>> +
>> +	spin_lock(&lock);
>> +	sclp_mark_busy();
>> +	info->h.length = PAGE_SIZE;
>> +	sclp_service_call(SCLP_READ_CPU_INFO, cpu_info_buffer);
>> +
>> +	if (smp_query_num_cpus() > 1)
>> +		printf("SMP: Initializing, found %d cpus\n", info->nr_configured);
>> +
>> +	cpus = calloc(info->nr_configured, sizeof(cpus));
>> +	for (i = 0; i < info->nr_configured; i++) {
>> +		if (info->entries[i].address == cpu0_addr) {
>> +			cpu0 = &cpus[i];
>> +			cpu0->stack = stackptr;
>> +			cpu0->lowcore = (void *)0;
>> +			cpu0->active = true;
> 
> So here cpus[i].active gets set to true ...
> 
>> +		}
>> +		cpus[i].addr = info->entries[i].address;
>> +		cpus[i].active = false;
> 
> ... but here it is set back to false.
> 
> Maybe move the if-statement below this line?
> 
>> +	}
>> +	spin_unlock(&lock);
>> +}
> [...]
>> diff --git a/s390x/cstart64.S b/s390x/cstart64.S
>> index 36f7cab..a45ea8f 100644
>> --- a/s390x/cstart64.S
>> +++ b/s390x/cstart64.S
>> @@ -172,6 +172,13 @@ diag308_load_reset:
>>  	lhi	%r2, 1
>>  	br	%r14
>>  
>> +.globl smp_cpu_setup_state
>> +smp_cpu_setup_state:
>> +	xgr	%r1, %r1
>> +	lmg     %r0, %r15, 512(%r1)
> 
> Can you use GEN_LC_SW_INT_GRS instead of 512?
> 
>> +	lctlg   %c0, %c0, 776(%r1)
> 
> ... and here GEN_LC_SW_INT_CR0 instead of 776?
> 
> Apart from that, the patch looks fine to me.

Thanks, just fixed that



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