On Mon, Sep 19, 2022 at 12:26 AM Like Xu <like.xu.linux@xxxxxxxxx> wrote: > > On 14/9/2022 7:42 am, Jim Mattson wrote: > > How does live migration work? I don't see any mechanism for recording > > the current LBR MSRs on suspend or restoring them on resume. > > Considering that LBR is still a model specific feature, migration is less > valuable unless > both LBR_FMT values of the migration side are the same, the compatibility check > (based on cpu models) is required (gathering dust in my to-do list); This seems like a problem best solved in the control plane. > and there is another dusty missing piece is how to ensure that vcpu can get LBR > hardware in > vmx transition when KVM lbr event fails in host lbr event competition, the > complexity here is > that the host and guest may have different LBR filtering options. In case of a conflict, who currently wins? The host or the guest? I'd like the guest to win, but others may feel differently. Maybe we need a configuration knob? > The good news is the Architecture LBR will add save/restore support since Paolo > is not averse to > putting more msr's into msrs_to_save_all[], perhaps a dynamic addition mechanism > is a prerequisite. > > Please let me know what your priority preferences are for these tasks above.
