On Fri, 18 Oct 2019, Xiaoyao Li wrote: > On 10/17/2019 8:29 PM, Thomas Gleixner wrote: > > The more I look at this trainwreck, the less interested I am in merging any > > of this at all. > > > > The fact that it took Intel more than a year to figure out that the MSR is > > per core and not per thread is yet another proof that this industry just > > works by pure chance. > > > > Whether it's per-core or per-thread doesn't affect much how we implement for > host/native. How useful. > And also, no matter it's per-core or per-thread, we always can do something in > VIRT. It matters a lot. If it would be per thread then we would not have this discussion at all. > Maybe what matters is below. > > > Seriously, this makes only sense when it's by default enabled and not > > rendered useless by VIRT. Otherwise we never get any reports and none of > > the issues are going to be fixed. > > > > For VIRT, it doesn't want old guest to be killed due to #AC. But for native, > it doesn't want VIRT to disable the #AC detection > > I think it's just about the default behavior that whether to disable the > host's #AC detection or kill the guest (SIGBUS or something else) once there > is an split-lock #AC in guest. > > So we can provide CONFIG option to set the default behavior and module > parameter to let KVM set/change the default behavior. Care to read through the whole discussion and figure out WHY it's not that simple? Thanks, tglx
