Re: [PATCH v14 111/113] RFC: KVM: x86, TDX: Add check for setting CPUID

From: Huang, Kai
Date: Wed Jun 14 2023 - 05:45:33 EST


On Tue, 2023-06-13 at 10:31 -0700, Isaku Yamahata wrote:
> On Tue, Jun 06, 2023 at 11:57:35PM +0000,
> "Huang, Kai" <kai.huang@xxxxxxxxx> wrote:
>
> > On Sun, 2023-05-28 at 21:20 -0700, isaku.yamahata@xxxxxxxxx wrote:
> > > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > >
> > > Add a hook to setting CPUID for additional consistency check of
> > > KVM_SET_CPUID2.
> > >
> > > Because intel TDX or AMD SNP has restriction on the value of cpuid. Some
> > > value can't be changed after boot. Some can be only set at the VM
> > > creation time and can't be changed later. Check if the new values are
> > > consistent with the old values.
> >
> > You might want to use some grammar tool to check against the changelog.
> >
> > Also, personally I think it's better to briefly mention why we choose this
> > design but not another (e.g., why we just don't make KVM remember all CPUIDs in
> > TDH.MNG.INIT and simply ignores/rejects further KVM_SET_CPUID2). It would be
> > helpful for the reviewer, or some git blamer in the future.
> >
>
> > And why this patch is placed at the very bottom of this series? This logic
> > should belong to TD creation part which should be at a relative earlier position
> > in this series.
>
> Because this is nice-to-have, not necessary for this patch series to work.

Is it? I thought Sean suggested we should to this.

I think you should just include it to this series and place it in a proper
position (or even merge it to some other patch).