------- Comment From mdr...@us.ibm.com 2018-04-05 12:50 EDT------- (In reply to comment #9) > So all that, to provide a -sxxm type that is NOT the default (not in your > patches, so I didn't make it the default in mine). > > 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. > > Since we are not changing the deafault (pseries-bionic) is what we > essentially support. > We don't even have to wrap it into the 2.11 type. > > Todays machine types in Bionic: > [Upstream types] > pseries-2.10 pSeries Logical Partition (PAPR compliant) > pseries-2.11 pSeries Logical Partition (PAPR compliant) > pseries-2.12 pSeries Logical Partition (PAPR compliant) > [...] > [Ubuntu recommended types (the defaults)] > pseries pSeries Logical Partition (PAPR compliant) (alias of > pseries-bionic) > pseries-bionic pSeries Logical Partition (PAPR compliant) (default) > [...] > > Your patch will add > pseries-2.12-sxxm based on the 2.12 that was added in the stable 2.11.1 > patches. > I mentioned this before on other places. > That might be a nice simplification for users, but since 2.12 is not yet set > in stone (at least it is on -rc now) we can't (and won't) make any > guarantees about cross release migrations. > > pseries-bionic is what we can control, and the default and what we consider > that shall work across releases. > Since you provided the extra type as non-default convenience type I'll do > the same. > > 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. > If you want any of these sxxm defaults to be the default of the default > machine type ... ARGL too much default exception. > Rephrase: > If you want the changes to the CAPs that the 2.12-sxxm type starts to be > applied to the default machine type "pseries-bionic" let me know. > > Until Bionic release we could set: > smc->default_caps.caps[SPAPR_CAP_CFPC] = SPAPR_CAP_WORKAROUND; > smc->default_caps.caps[SPAPR_CAP_SBBC] = SPAPR_CAP_WORKAROUND; > smc->default_caps.caps[SPAPR_CAP_IBS] = SPAPR_CAP_FIXED_CCD; > In the pseries-bionic type (but not after release anymore). > > 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. 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). 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: 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 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. ------- Comment From mdr...@us.ibm.com 2018-04-05 12:51 EDT------- *** Bug 166063 has been marked as a duplicate of this bug. *** -- 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