> > > I wonder, what is the benefit of this then. > > If users need to change the machine type, then they can just as well set > the > > CFPC/SBBC/IBS caps right? > > I believe the issue is similar to what we initially hit with: > > Bug 165081 - LP1752026- Ubuntu18.04:POWER9:DD2.2: Unable to start a KVM > guest with default machine type(pseries-bionic) complaining "KVM > implementation does not support Transactional Memory, try cap-htm=off" > (kvm) > > where due to lack of "-machine pseries-*,cap-*=on/off/*" support via > libvirt we need to rely on machine type behavior to enable certain > options in the interim. >
Yes exactly. And this is why I was asking for more guidance on the preferred defaults, as the addition of an extra type still needs the user to do something (e.g. selecting that type). [...] > IFF there are changes to 2.12 in the remaining upstream 2.12 or the coming > > Ubuntu 18.10 development cycle we will not try (too hard) to keep e.g. a > > Bionic pseries-2.12-sxxm in sync with that of 18.10. > > Doesn't seem likely to change at this point but that seems reasonable > either way. > Yeah, as much as upstream can't change 2.11 anymore (which is why you make it a 2.12 type) we can't change 2.12 yet (in this release). [...] > Same (=please let me know asap) is true if instead you want any of: > > pseries-2.11-sxxm > > pseries-bionic-sxxm > > Adding pseries-2.11-sxxm/pseries-bionic-sxxm gives us some flexibility > with different firmware/hardware and migration strategies so this would > be our preference. Ok, will do so. We will keep the 2.12 type as-is in code, but it might change (if it changes upstream - unlikely). While together we will try to keep the bionic types stable. > This is also in line with how things are done with > spectre-related CPU capabilities in 2.12/2.11.1 for x86 (new explicit > cpu types as opposed to changed defaults). > Yes, that is true on x86 > In terms of upstream patches that need to be backported I think we also > want "ppc/spapr-caps: Disallow setting workaround for spapr-cap-ibs". I > got a pretty clean backport on top of 2.11.1 just cherry-picking: > I already have this patch in my current build - I added it to the description here when I was dupping the other bug onto this. > > ppc/spapr-caps: Define the pseries-2.12-sxxm machine type > ppc/spapr-caps: Convert cap-ibs to custom spapr-cap > ppc/spapr-caps: Disallow setting workaround for spapr-cap-ibs > ppc/spapr-caps: Convert cap-sbbc to custom spapr-cap > ppc/spapr-caps: Convert cap-cfpc to custom spapr-cap > ppc/spapr-caps: Add support for custom spapr_capabilities > target/ppc: Check mask when setting cap_ppc_safe_indirect_branch > That is exactly the series I already have in my ppa since yesterday ~noon > Then an ubuntu-specific pseries-2.11-sxxm patch would basically mirror > the "ppc/spapr-caps: Define the pseries-2.12-sxxm machine type" > implementation and pseries-bionic-sxxm could point to that. > Exactly my thought will do so and respin the build in the ppa. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1761372 Title: backport needed for spectre/meltdown mitigation machine type qemu patches (kvm) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1761372/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
