Re: [PATCH/RFC 5/9] KVM: s390: introduce post handlers for STSI

[Paolo Bonzini <pbonzini@redhat.com>]

On 16/03/2015 13:18, Christian Borntraeger wrote:
> Its up to a page and the content depends on the function code, selector1
> and selector2.
> See arch/s390/kernel/sysinfo.c for the details or zarchitecture principles of
> opration the STSI instruction.
> 
> 
> Some time ago we had patches that passed the guest name
> and UUID into the kernel - then Alex Graf asked, why we cant do that in 
> userspace.
> https://lists.nongnu.org/archive/html/qemu-devel/2014-04/msg00094.html
> 
> Now, stsi also gives the bare information as provides by upper
> layers: e.g. 2.2.2 gives basic LPAR information. When doing that under
> KVM or z/VM, KVM or z/VM will pass that information along to the underlying 
> LPAR hypervisor and give the result back to the guest.
> 
> So I came up with the idea to let KVM do what it needs but also allow
> QEMU to override (3.2.2 - this 2nd level hypervisor)

If it's up to a page it definitely makes sense to do it this way.

Thanks,

Paolo