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
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