Re: [kvm-unit-tests 3/5] lib: s390x: sie: Free guest memory on destroy

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

On 4/15/26 16:21, Nico Boehr wrote:
> On Wed Apr 15, 2026 at 10:45 AM CEST, Janosch Frank wrote:
>> We never freed the memory that the sie library allocates as the guest
>> ram on destruction of the VM. Most tests reuse the VM or just leak the
>> memory since the standard allocation is one megabyte and tests only
>> use single digit numbers of VMs.
>>
>> It's time to add automatic freeing to the sie library when a VM is
>> destroyed.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>   lib/s390x/sie.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/lib/s390x/sie.c b/lib/s390x/sie.c
>> index a49c45c7..758ead77 100644
>> --- a/lib/s390x/sie.c
>> +++ b/lib/s390x/sie.c
>> @@ -192,4 +192,5 @@ void sie_guest_destroy(struct vm *vm)
>>   	free_page(vm->sblk);
>>   	if (vm->sblk->ecb2 & ECB2_ESCA)
>>   		free_page(vm->sca);
>> +	free_pages((void *)virt_to_pte_phys(get_page_root(), vm->guest_mem));
>>   }
> 
> Is there a particular reason why we have a two-step process of calling
> sie_guest_alloc() for memory allocation
> and then
> sie_guest_create() for initializing the sie_block etc
> 
> but
> sie_guest_destroy()
> cleans up both?
> 

Historical reasons I guess.
There've been a lot of changes to the SIE lib over the years, snippet 
support itself isn't that consistent but it's currently good enough.
s390x/sie.c is the only direct user of the allocation and even that 
usage looks like it could be converted.