Re: [PATCH] s390x: kvm: Fix number of cpu reports for stsi 3.2.2

[David Hildenbrand <david@redhat.com>]

On 31.03.20 12:11, Cornelia Huck wrote:
> On Mon, 30 Mar 2020 18:04:09 +0200
> David Hildenbrand <david@redhat.com> wrote:
> 
>> On 30.03.20 17:38, Janosch Frank wrote:
>>> The cpu number reporting is handled by KVM and QEMU only fills in the
>>> VM name, uuid and other values.
>>>
>>> Unfortuantely KVM doesn't report reserved cpus and doesn't even know  
>>
>> s/Unfortuantely/Unfortunately/
>>
>>> they exist until the are created via the ioctl.
>>>
>>> So let's fix up the cpu values after KVM has written its values to the
>>> 3.2.2 sysib.  
>>
>> Maybe mention "similar to TCG in target/s390x/misc_helper.c:HELPER(stsi)".
>>
>>>
>>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>>> ---
>>>  target/s390x/kvm.c | 18 +++++++++++++++++-
>>>  1 file changed, 17 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
>>> index 3630c15f45a48864..a1c4890bdf0c65e4 100644
>>> --- a/target/s390x/kvm.c
>>> +++ b/target/s390x/kvm.c
>>> @@ -1819,8 +1819,10 @@ static int handle_tsch(S390CPU *cpu)
>>>  
>>>  static void insert_stsi_3_2_2(S390CPU *cpu, __u64 addr, uint8_t ar)
>>>  {
>>> +    const MachineState *ms = MACHINE(qdev_get_machine());
>>> +    uint16_t total_cpus = 0, conf_cpus = 0, reserved_cpus = 0;
>>>      SysIB_322 sysib;
>>> -    int del;
>>> +    int del, i;
>>>  
>>>      if (s390_is_pv()) {
>>>          s390_cpu_pv_mem_read(cpu, 0, &sysib, sizeof(sysib));
>>> @@ -1842,6 +1844,20 @@ static void insert_stsi_3_2_2(S390CPU *cpu, __u64 addr, uint8_t ar)
>>>          memset(sysib.ext_names[del], 0,
>>>                 sizeof(sysib.ext_names[0]) * (sysib.count - del));
>>>      }
>>> +
>>> +    /* count the cpus and split them into configured and reserved ones */
>>> +    for (i = 0; i < ms->possible_cpus->len; i++) {
>>> +        total_cpus++;
>>> +        if (ms->possible_cpus->cpus[i].cpu) {
>>> +            conf_cpus++;
>>> +        } else {
>>> +            reserved_cpus++;
>>> +        }
>>> +    }  
>>
>> We could of course factor this calculation out :)
>>
>> (and one could shrink the variables from 3 to 2)
> 
> I'd vote for queuing this one on s390-fixes now (with the patch
> description tweaks) and doing any cleanup on top for the next release.
> Ok?

Fine with me.


-- 
Thanks,

David / dhildenb