Re: [kvm-unit-tests PATCH v3 1/9] s390x: uv-host: Fix UV init test memory allocation

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

On 5/10/23 10:51, Nico Boehr wrote:
> Quoting Janosch Frank (2023-05-02 15:07:24)
>> The init memory has to be above 2G and 1M aligned but we're currently
>> aligning on 2G which means the allocations need a lot of unused
>> memory.
> 
> I know I already gave my R-b here, but...
> 
>> diff --git a/s390x/uv-host.c b/s390x/uv-host.c
>> index 33e6eec6..9dfaebd7 100644
>> --- a/s390x/uv-host.c
>> +++ b/s390x/uv-host.c
>> @@ -500,14 +500,17 @@ static void test_config_create(void)
>>   static void test_init(void)
>>   {
>>          int rc;
>> -       uint64_t mem;
>> +       uint64_t tmp;
>>   
>> -       /* Donated storage needs to be over 2GB */
>> -       mem = (uint64_t)memalign_pages_flags(SZ_1M, uvcb_qui.uv_base_stor_len, AREA_NORMAL);
> 
> ...maybe out of coffee, but can you point me to the place where we're aligning
> to 2G here? I only see alignment to 1M and your change only seems to rename
> mem to tmp:
> 
>> +       /*
>> +        * Donated storage needs to be over 2GB, AREA_NORMAL does that
>> +        * on s390x.
>> +        */

This comment explains it :)
Its a re-name of mem to tmp and an extension of this comment so it makes 
more sense.

>> +       tmp = (uint64_t)memalign_pages_flags(SZ_1M, uvcb_qui.uv_base_stor_len, AREA_NORMAL);