[systemd-devel] [PATCH] systemd-detect-s390-virt: add virtualization detection on s390x

[Thomas Blume]

On Mon, 7 Jul 2014, Lennart Poettering wrote:

>> IMHO the main difference is the level of maturity.
>> z/VM is about 30 years old and has a huge amount of tools for everything you
>> could imagine. KVM is relatively new and under heavy development.
>> Furthermore, KVM is bound to the linux kernel, while z/VM is not.
>> Finally, KVM could theoretically run inside z/VM (thought it doesn't make sense
>> running KVM on an already virtualized CPU) but not vice-versa.
>>
>> Kay, my colleague Ihno told me that you were working in the s390 department at SUSE.
>> Any opinion about the use of distinguishing z/VM from KVM under s390?
>
> Well, obviously, we should distuingish kvm from some s390-specific
> virtualization. I was mostly referring to your original's patch
> distinction between "PR/SM" and "z/VM". What is that about?
>

Ah, sorry for the misunderstanding.
PR/SM is the primary hypervisor that runs on the physical hardware, whereas
z/VM can only run on top of PR/SM, but not below.
Under PR/SM, the system resources can be partitioned first via LPAR and then
by running a z/VM on each LPAR.
However, apart from determining the level of virtualization, I don't see much
practical relevance in making a distinction.

Regards
Thomas