On Mon, 2022-11-07 at 21:43 -0800, Isaku Yamahata wrote: > On Tue, Nov 08, 2022 at 01:09:27AM +0000, > "Huang, Kai" <kai.huang@xxxxxxxxx> wrote: > > > On Mon, 2022-11-07 at 13:46 -0800, Isaku Yamahata wrote: > > > > On Fri, Nov 04, 2022, Isaku Yamahata wrote: > > > > > Thanks for the patch series. I the rebased TDX KVM patch series and it > > > > > worked. > > > > > Since cpu offline needs to be rejected in some cases(To keep at least one > > > > > cpu > > > > > on a package), arch hook for cpu offline is needed. > > > > > > > > I hate to bring this up because I doubt there's a real use case for SUSPEND > > > > with > > > > TDX, but the CPU offline path isn't just for true offlining of CPUs. When > > > > the > > > > system enters SUSPEND, only the initiating CPU goes through > > > > kvm_suspend()+kvm_resume(), > > > > all responding CPUs go through CPU offline+online. I.e. disallowing all > > > > CPUs from > > > > going "offline" will prevent suspending the system. > > > > > > The current TDX KVM implementation disallows CPU package from offline only > > > when > > > TDs are running. If no TD is running, CPU offline is allowed. So before > > > SUSPEND, TDs need to be killed via systemd or something. After killing TDs, > > > the > > > system can enter into SUSPEND state. > > > > This seems not correct. You need one cpu for each to be online in order to > > create TD as well, as TDH.MNG.KEY.CONFIG needs to be called on all packages, > > correct? > > That's correct. In such case, the creation of TD fails. TD creation checks if > at least one cpu is online on all CPU packages. If no, error. I think we can just always refuse to offline the last cpu for each package when TDX is enabled. It's simpler I guess.
