Re: [PATCHv2 0/4] x86/tdx: Adjust TD settings on boot

kirill.shutemov
2024-04-12T15:02:02Z

On Wed, Apr 10, 2024 at 02:41:13PM +0000, Edgecombe, Rick P wrote:
> On Wed, 2024-04-10 at 17:37 +0300, Kirill A. Shutemov wrote:
> > On Mon, Mar 25, 2024 at 12:46:03PM +0200, Kirill A. Shutemov wrote:
> > > Adjust TD setting on boot:
> > >
> > >    - Disable EPT violation #VE on private memory if TD can
> > >      control it;
> > >
> > >    - Enable virtualization of topology-related CPUID leafs
> > >      X2APIC_APICID MSR;
> >
> > Any feedback?
>
> It is missing a lot of the normal things that come in coverletters like what is
> the problem and importance. It might help attract more review.

What about this:

The patchset adjusts a few TD settings on boot for the optimal functioning
of the system:

- Disable EPT violation #VE on private memory if TD can control it

The newer TDX module allows the guest to control whether it wants to
see #VE on EPT violation on private memory. The Linux kernel does not
want such #VEs and needs to disable them.

- Enable virtualization of topology-related CPUID leafs X2APIC_APICID MSR;

The ENUM_TOPOLOGY feature allows the VMM to provide topology
information to the guest. Enabling the feature eliminates
topology-related #VEs: the TDX module virtualizes accesses to the
CPUID leafs and the MSR.

It allows TDX guest to run with non-trivial topology configuration.
--
Kiryl Shutsemau / Kirill A. Shutemov