Re: [PATCH v3 2/9] s390: ap: kvm: setting a hook for PQAP instructions

Pierre Morel
2019-02-15T09:55:57Z

On 15/02/2019 10:26, Cornelia Huck wrote:
> On Thu, 14 Feb 2019 17:45:06 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
>
>> On 14/02/2019 16:54, Cornelia Huck wrote:
>>> On Thu, 14 Feb 2019 14:51:02 +0100
>>> Pierre Morel <pmorel@linux.ibm.com> wrote:
>>>
>>>> This patch adds interception code for the PQAP instructions,
>>>> and a callback inside the KVM arch structure for s390.
>>>>
>>>> If a VFIO-AP drivers needs to intercept PQAP/AQIC or PQAP/TAPQ
>>>
>>> s/drivers/driver/
>>
>> thanks. OK
>>
>
>>>> + *
>>>> + * This callback only handles PQAP/AQIC instruction and
>>>
>>> Here you only talk about PQAP/AQIC, what about PQAP/TAPQ mentioned in
>>> the patch description?
>>
>> I can add "for now" or "in this patch" or suppress the reference to
>> PAPQ/TAPQ
>
> I'd just add a note to the patch description that this patch only
> handles PQAP/AQCI and that handling PQAP/TAPQ is something for a
> follow-on patch.

OK, I will clear this.
Thanks

>
>>
>>>

...snip...

>>>> + /* PQAP instructions are allowed for guest kernel only */
>>>> + if (vcpu->arch.sie_block->gpsw.mask & PSW_MASK_PSTATE)
>>>> + return kvm_s390_inject_program_int(vcpu, PGM_PRIVILEGED_OP);
>>>> + /* AQIC instruction is allowed only if facility 65 is available */
>>>> + if (!test_kvm_facility(vcpu->kvm, 65))
>>>> + return kvm_s390_inject_program_int(vcpu, PGM_SPECIFICATION);
>>>> + /* All right, call the callback */
>>>> + return vcpu->kvm->arch.crypto.pqap_hook(vcpu);
>>>
>>> Can that callback also return -EOPNOTSUPP to order to drop to user
>>> space?
>>
>> Yes.
>> Why not?
>
> Maybe also mention that in the function description?
>

Will do thanks.

Regards,
Pierre

--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany