On Wed, Oct 25, 2017 at 05:50 PM +0200, David Hildenbrand <david@xxxxxxxxxx> wrote: > On 25.10.2017 17:09, Boris Fiuczynski wrote: >> On 10/25/2017 12:23 PM, David Hildenbrand wrote: >>> On 25.10.2017 12:18, Christian Borntraeger wrote: >>>> Ping, I plan to submit belows patch for 2.11. We can then still look into >>>> a libvirt<->qemu interface for limiting host-model depending on machine versions >>>> (or not). >>> >>> I think this would be sufficient for now. >>> >>> Having different host models, depending on the the machine type sounds >>> wrong. But maybe we'll need it in the future. >>> >> >> David, I disagree if your proposal is to generally tolerate new cpu >> features in old machine types. This *might* work for gs but how do you >> guaranty that guests do not behave differently/wrong when suddenly new >> cpu features are made available to guest when (re-)starting them. >> That is my feedback for the qemu side of this mater. > > Just re-reading this section, so what you mean is: > > a) guest is started, host model is copied and used. guest works. > b) guest is stopped. > c) QEMU/KVM/HW is updated. > d) guest is started, new host model is copied. guest no longer works. > > d) could be because there are now some additional features with e.g. > broken guest implementation or now missing features. > > > What you propose (if I am not wrong) is a to bind features somehow to a > QEMU machine. I think that should never be done. You could not catch now > missing features. What exactly do you mean by the last sentence? > > What would you think about a persistent host-model copy option? So > instead of copying at every start, only copy and replace it once in the XML? > > Easy to specify by the user and no CPU feature changes will happend > "blindly". > > > -- > > Thanks, > > David > -- Beste Grüße / Kind regards Marc Hartmayer IBM Deutschland Research & Development GmbH Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294 -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
