Re: [edk2-devel] [RFC] Design review for Lazy Page Accept in TDVF

["Gerd Hoffmann" <kraxel@redhat.com>]

On Fri, Sep 03, 2021 at 12:31:57AM +0000, Yao, Jiewen wrote:
> Hi
> It is good idea to have a protocol to abstract TDX and SEV.
> 
> I think we need clearly document what service can be used in EFI_ACCEPT_MEMORY.
> For example, can we use memory allocation service, GCD service, or MP service?

Likewise the expected behavior.  For example whenever the protocol
driver or the memory core should update the GCD maps.

> Couple of dependency issue:
> If EFI_ACCEPT_MEMORY cannot use MP service, then there might be performance concern.
> If it uses MP service, then we need ensure MP service is installed earlier and before memory accept request.
> I think we need a way to ensure there is enough memory *before* the protocol is installed, right?

Yes.  Same for booting the OS, the kernel must have enough memory so it
can boot up to the point where the driver handling the lazy page accept
loads.

We should also define how we hand over memory range state from one stage
to the other (see also my reply to the sev-snp series posted yesterday)
so ovmf knows which ranges are accepted/validated already.

take care,
  Gerd