On 06.03.2018 12:53, Christian Borntraeger wrote:
>
>
> On 03/06/2018 12:38 PM, Christian Borntraeger wrote:
>> On 03/06/2018 12:32 PM, Christian Borntraeger wrote:
>>> David,
>>>
>>> this seems to have broken VSIE für guests with >64vcpus as we only pin
>>> the first page of the SCA. Starting guest3 with 240 vcpu triggers
>>> quickly guest2 crashes. Can you have a look?
>>>
>>
>> Hmm, or maybe it was always broken and we never supported pinning of
>> ESCA properly?
>
> 4.15.0 is also broken, must be an earlier change.
>
We never claimed ESCA support for L2 (because all SCA CPU entries are
invalid). But I once implemented support for > 64 CPUs if all entries
are unused in kvm
commit a6940674c384ebf56aa0c44f417032de2b67100c
Author: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Date: Mon Aug 8 22:39:32 2016 +0200
KVM: s390: allow 255 VCPUs when sca entries aren't used
If the SCA entries aren't used by the hardware (no SIGPIF), we
can simply not set the entries, stick to the basic sca and allow more
than 64 VCPUs.
To hinder any other facility from using these entries, let's properly
provoke intercepts by not setting the MCN and keeping the entries
unset.
This effectively allows when running KVM under KVM (vSIE) or under
z/VM to
provide more than 64 VCPUs to a guest. Let's limit it to 255 for now, to
not run into problems if the CPU numbers are limited somewhere else.
Signed-off-by: David Hildenbrand <dahi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Maybe something was broken in that part of the code.
--
Thanks,
David / dhildenb
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