Re: [edk2-devel] measurement to command-line/initrd for loading kernel via -kernel option

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

On Wed, Sep 21, 2022 at 11:24:11AM +0000, Lu, Ken wrote:
> > 
> > > But either in GenericQemuLoadImageLib, it can do measurement for
> > command line and initrd, correct?
> > 
> > Yes, it could.  But why given that the linux kernel efi stub measures anyway?

> If the final decision is the measurement should be done by efi stub in
> Linux kernel.

The reference should be the workflow when you boot linux from efi shell
or using a BootNNNN entry.  Which I think is:

  (1) linux kernel is loaded + measured via Loadimage().
  (2) linux kernel is started via efi stub entry point.
  (3) linux kernel efi stub loads and measures the initrd.

Not fully sure about the command line measurement, IIRC Ard described
that in one of the replies.

> Do we also need remove today's measurement in Grub (I
> have submitted some patch for TDX in grub...)?

Those patches are perfectly fine, tpm measurement and tdx measurement
should be consistent.  In case the grub measurement workflow needs
changes to avoid double measurements (not sure this is actually the
case) those changes should apply to both tpm and tdx.

> According to Bottomley, the same measurement should not be done twice.

Yes, this is the way it should be, although the current state of affairs
is a bit messy and I think we are a bit away from that ideal.

> Or only the one who use GenericQemuLoadImageLib, will give the Linux
> kernel efi stub for measure?

I think we don't have to do anything special in GenericQemuLoadImageLib
because the lib uses Loadimage() which should handle measurement.

take care,
  Gerd