Re: [PATCH v19 039/130] KVM: TDX: initialize VM with TDX specific parameters

Isaku Yamahata
2024-04-11T20:46:30Z

On Thu, Apr 11, 2024 at 07:51:55PM +0000,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com> wrote:

> On Thu, 2024-04-11 at 12:26 -0700, Isaku Yamahata wrote:
> > >
> > > So this enables features based on xss support in the passed CPUID, but these
> > > features are not
> > > dependent xsave. You could have CET without xsave support. And in fact
> > > Kernel IBT doesn't use it. To
> > > utilize CPUID leafs to configure features, but diverge from the HW meaning
> > > seems like asking for
> > > trouble.
> >
> > TDX module checks the consistency.  KVM can rely on it not to re-implement it.
> > The TDX Base Architecture specification describes what check is done.
> > Table 11.4: Extended Features Enumeration and Execution Control
>
> The point is that it is an strange interface. Why not take XFAM as a specific
> field in struct kvm_tdx_init_vm?

Now I see your point. Yes, we can add xfam to struct kvm_tdx_init_vm and
move the burden to create xfam from the kernel to the user space.
--
Isaku Yamahata <isaku.yamahata@intel.com>