On 25/01/2023 3:24 pm, Jan Beulich wrote: > Versions of the two final patches were submitted standalone earlier > on. The series here tries to carry out a suggestion from Andrew, > which the two of us have been discussing. Then said previously posted > patches are re-based on top, utilizing the new functionality. > > 1: spec-ctrl: add logic to issue IBPB on exit to guest > 2: spec-ctrl: defer context-switch IBPB until guest entry > 3: limit issuing of IBPB during context switch > 4: PV: issue branch prediction barrier when switching 64-bit guest to kernel > mode
In the subject, you mean IBPB. I think all the individual patches are fine. Do you have an implementation of VMASST_TYPE_mode_switch_no_ibpb for Linux yet? The thing I'd like to avoid is that we commit this perf it to Xen, without lining Linux up to be able to skip it. ~Andrew