On 05.11.18 16:36, Halil Pasic wrote:
>
>
> On 11/05/2018 04:14 PM, Michael Mueller wrote:
>>
>>
>> On 05.11.18 15:51, Pierre Morel wrote:
>>> On 25/10/2018 14:37, Michael Mueller wrote:
> [..]
>>>> +
>>>> +void kvm_s390_gib_init(u8 nisc)
>>>> +{
>>>> + int rc;
>>>> +
>>>> + if (gib)
>>>> + return;
>>>> +
>>>> + if (!css_general_characteristics.aiv) {
>>>> + KVM_EVENT(3, "%s", "gib not initialized, no AIV facility");
>>>> + return;
>>>> + }
>>>> +
>>>> + gib = (struct kvm_s390_gib *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
>>>> + if (!gib) {
>>>> + KVM_EVENT(3, "%s", "gib memory allocation failed");
>>>> + return;
>>>> + }
>>>
>>> Why should we survive this error?
>>
>> Design question.
>>
>
> I'm with Pierre on this one. We should fail starting the guest
> if this allocation fails.
>
Halil, the GIB is global to KVM, we would need to fail loading/init of
KVM, which I'd like to avoid.
Neither GIB nor gisa is necessary for a VM to run, so we shouldn't stop
on an error.
>>>
>>>
>>>> +
>>>> + gib->nisc = nisc;
>>>> + rc = chsc_sgib((u32)(u64)gib);
>>>> + if (rc) {
>>>> + KVM_EVENT(3, "gib 0x%pK AIV association failed rc: %d",
>>>> + gib, rc);
>>>> + free_page((unsigned long)gib);
>>>> + gib = NULL;
>>>> + return;
>>>> + }
>>>
>>> or this failure ?
>>>
>>> shouldn't we better return an error and abort loading KVM?
>>
>> Design question.
>>
>
> Same here I guess. This would be only either due to a guest or
> a host bug, or?
>
> I would prefer being fairly deterministic about whether we do have
> a gib or not.
Same as above
>
> Regards,
> Halil
>
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