Re: [PATCH 2/5] efi/x86: Implement support for unaccepted memory

Kirill A. Shutemov
2021-08-10T19:08:59Z

On Tue, Aug 10, 2021 at 11:30:42AM -0700, Dave Hansen wrote:
> On 8/9/21 11:26 PM, Kirill A. Shutemov wrote:
> > +config UNACCEPTED_MEMORY
> > + bool
> > + depends on EFI_STUB
> > + help
> > + Some Virtual Machine platforms, such as Intel TDX, introduce
> > + the concept of memory acceptance, requiring memory to be accepted
> > + before it can be used by the guest. This protects against a class of
> > + attacks by the virtual machine platform.
> > +
> > + This option adds support for unaccepted memory and makes such memory
> > + usable by kernel.
>
> Do we really need a full-blown user-visible option here? If we, for
> instance, just did:
>
> config UNACCEPTED_MEMORY
> bool
> depends on EFI_STUB
>
> it could be 'select'ed from the TDX Kconfig and no users would ever be
> bothered with it. Would a user *ever* turn this on if they don't have
> TDX (or equivalent)?

But it's already not user selectable. Note that there's no prompt next to
the "bool". The "help" section is just for documentation. I think it can
be useful.

--
Kirill A. Shutemov