Re: [PATCH net-next v3 7/7] net/smc: manage system EID in SMC stack instead of ISM driver

[Alexandra Winter <wintera@linux.ibm.com>]

On 04.12.23 13:36, Wen Gu wrote:
>> Here we only check the first smcd device to determine whether we support v2.
>> Which is ok, for today's platform firmware ISM devices, as they are always the same version.
>>
>> When you add virtual ISM devices (loopback-ism, virtio-ism) then this needs to be changed.
>> IMO the logic then needs to be "if all smcd devices support v2,
>> then smc_ism_v2_capable = true;
>> else smc_ism_v2_capable = false;"
>>
> 
> Thank you. I will change this in the loopback-ism patch set.
> 
> But I am wondering if loopback-ism coexists with s390 ISMv1, why smc_ism_v2_capable shouldn't be set?
> Is it because the SEID generated in this way is not correct if the s390 ISMv2 does not exist?

I think you're right: 'At least one IMSv2 device' is sufficient for smc_ism_v2_capable.

Actually, we could even always do smc_ism_v2_capable=true, and append an empty ISMv2 device list.
(I am not sure that would be a good idea...)

Interesting sceanrios to consider for ism-loopback:
e.g.: 2 ISMv1 device and 1 ism-loopback...