Re: [PATCH v9 2/2] s390/kvm: diagnose 0x318 sync and reset

Collin Walling
2020-06-22T16:45:59Z

On 6/22/20 12:35 PM, Cornelia Huck wrote:
> On Mon, 22 Jun 2020 12:23:45 -0400
> Collin Walling <walling@linux.ibm.com> wrote:
>
>> Mind if I get some early feedback for the first run? How does this sound:
>>
>> 8.24 KVM_CAP_S390_DIAG318
>> -------------------------
>>
>> :Architecture: s390
>>
>> This capability allows for information regarding the control program
>> that may be observed via system/firmware service events. The
>> availability of this capability indicates that KVM handling of the
>> register synchronization, reset, and VSIE shadowing of the DIAGNOSE
>> 0x318 related information is present.
>>
>> The information associated with the instruction is an 8-byte value
>> consisting of a one-byte Control Program Name Code (CPNC), and a 7-byte
>> Control Program Version Code (CPVC). The CPNC determines what
>> environment the control program is running in (e.g. Linux, z/VM...), and
>> the CPVC is used for extraneous information specific to OS (e.g. Linux
>> version, Linux distribution...)
>>
>> The CPNC must be stored in the SIE block for the CPU that executes the
>> diag instruction, which is communicated from userspace to KVM via
>> register synchronization using the KVM_SYNC_DIAG318 flag. Both codes are
>> stored together in the kvm_vcpu_arch struct.
>
> Hm... what about replacing that last paragraph with
>
> "If this capability is available, the CPNC and CPVC are available for
> synchronization between KVM and userspace via the sync regs mechanism
> (KVM_SYNC_DIAG318)."
>
> ?
>

I like it!

--
Regards,
Collin

Stay safe and stay healthy