On 28.08.2017 21:38, Christian Borntraeger wrote:
>
>
> On 08/28/2017 09:35 PM, Christian Borntraeger wrote:
>>
>>
>> On 08/28/2017 09:27 PM, David Hildenbrand wrote:
>>>
>>>> rc = handle_sigp_dst(vcpu, order_code, cpu_addr,
>>>> diff --git a/arch/s390/tools/gen_facilities.c b/arch/s390/tools/gen_facilities.c
>>>> index 025ea20..181db5b 100644
>>>> --- a/arch/s390/tools/gen_facilities.c
>>>> +++ b/arch/s390/tools/gen_facilities.c
>>>> @@ -80,6 +80,7 @@ static struct facility_def facility_defs[] = {
>>>> 78, /* enhanced-DAT 2 */
>>>> 130, /* instruction-execution-protection */
>>>> 131, /* enhanced-SOP 2 and side-effect */
>>>> + 138, /* configuration z/architecture mode (czam) */
>>>> 146, /* msa extension 8 */
>>>> -1 /* END */
>>>> }
>>>>
>>>
>>> Thinking about it, this should be the right thing to do instead of the
>>> last hunk:
>>>
>>> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
>>> index 84c069afc02f..39115f5a38df 100644
>>> --- a/arch/s390/kvm/kvm-s390.c
>>> +++ b/arch/s390/kvm/kvm-s390.c
>>> @@ -1927,6 +1927,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned
>>> long type)
>>> memcpy(kvm->arch.model.fac_list, kvm->arch.model.fac_mask,
>>> S390_ARCH_FAC_LIST_SIZE_BYTE);
>>>
>>> + /* we are always in CZAM mode - even on pre z14 machines */
>>> + set_kvm_facility(kvm->arch.model.fac_mask, 138);
>>> + set_kvm_facility(kvm->arch.model.fac_list, 138);
>>> + /* we emulate STHYI in kvm */
>>> set_kvm_facility(kvm->arch.model.fac_mask, 74);
>>> set_kvm_facility(kvm->arch.model.fac_list, 74);
>>> if (MACHINE_HAS_TLB_GUEST) {
>>>
>>> That would produce consistent results for very old QEMU.
>>>
>>
>> This should be identical as the initial fac_list is populated from the fac_mask,
>> which is populated by the facility_defs structure.
>>
>> [..]
>> /* Populate the facility list initially. */
>> kvm->arch.model.fac_list = kvm->arch.sie_page2->fac_list;
>> ----> memcpy(kvm->arch.model.fac_list, kvm->arch.model.fac_mask,
>> S390_ARCH_FAC_LIST_SIZE_BYTE);
>>
>> [,..]
>
> Well not identical. The patch actually enables the czam facility only if the host
> hardware while your variant enables it always. Interesting discussion if it matters
> if we should enable it on z13, z12 and earlier or not
>
This is also what we do on the QEMU side and what I meant by "consistent".
--
Thanks,
David
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