Messages in this thread | | | Date | Mon, 27 Feb 2023 13:48:09 -0800 | From | Isaku Yamahata <> | Subject | Re: [PATCH v11 021/113] KVM: TDX: Refuse to unplug the last cpu on the package |
| |
On Mon, Jan 16, 2023 at 10:23:16AM +0000, "Huang, Kai" <kai.huang@intel.com> wrote:
> On Thu, 2023-01-12 at 08:31 -0800, isaku.yamahata@intel.com wrote: > > From: Isaku Yamahata <isaku.yamahata@intel.com> > > > > In order to reclaim TDX HKID, (i.e. when deleting guest TD), needs to call > > TDH.PHYMEM.PAGE.WBINVD on all packages. If we have used TDX HKID, refuse > > to offline the last online cpu. Add arch callback for cpu offline. > > I think it is worth to talk about suspend staff, i.e. why we only refuse to > offline the last cpu when there's active TD, but not choose to offline the last > cpu when TDX is enabled in KVM. People may not be able to understand > immediately the reason behind this design.
Updated the comment.
> Btw, I certainly don't want to speak for Sean, but it seems this was suggested > by Sean? If so, add a 'Suggested-by' tag?
Added suggested-by.
> > > > Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> > > --- > > > > [snip] > > > + > > +int tdx_offline_cpu(void) > > +{ > > + int curr_cpu = smp_processor_id(); > > + cpumask_var_t packages; > > + int ret = 0; > > + int i; > > + > > + if (!atomic_read(&nr_configured_hkid)) > > + return 0; > > As mentioned above, I think it also worth to add some comment here. When people > are trying to understand some code, I think mostly they are just going to look > at the code itself, but won't use 'git blame' to dig out the entire changelog to > understand some code.
Makes sense. Added a comment. -- Isaku Yamahata <isaku.yamahata@gmail.com>
| |