On 05.12.18 12:54, Cornelia Huck wrote: > On Wed, 5 Dec 2018 09:27:44 +0100 > Christian Borntraeger <borntrae...@de.ibm.com> wrote: > >> On 05.12.2018 09:26, David Hildenbrand wrote: >>> On 04.12.18 23:18, Collin Walling wrote: >>>> Add migration and reset support for diagnose 318. This is a new z14 GA2 >>>> hardware feature, but we can provide guest support starting with the >>>> zEC12-full CPU model. >>>> >>>> Because new hardware introduces a new facility-availability byte in >>>> the Read SCP Info block, we lose one byte in the CPU entries list >>>> and must limit the maximum VCPUs to 247 (down from 248). >>> >>> This could break setups that upgrade/migrate. At least forward migration >>> can be broken. Do we care about that? >> >> Can we maybe bind this feature and the cpu limit to the 4.0 machine? > > I think that would make sense.
Won't be that easy, as we'll have different sizes of the struct size. Something that might uglify the code quite a bit. Also we'll get a dependence between the cpu model features (e.g. probed via the NULL machine) and the compat machine. Have to think about this. > >>> >>> Can you split off >>> >>> 1. linux-header changes >>> 2. CPU model changes? (introduction and definition of new feature, but >>> not when it is used?) >>> >>>> >>>> Signed-off-by: Collin Walling <wall...@linux.ibm.com> >>>> --- -- Thanks, David / dhildenb
