OvmfPkg/EnrollDefaultKeys: enroll PK/KEK1 from the Type 11 SMBIOS table

OvmfPkg/EnrollDefaultKeys: enroll PK/KEK1 from the Type 11 SMBIOS table

Disconnect the certificate that is enrolled as both Platform Key and first
Key Exchange Key from Red Hat: expect the hypervisor to specify it, as
part of SMBIOS.

Example usage with QEMU:

* Generate self-signed X509 certificate:

  openssl req \
    -x509 \
    -newkey rsa:2048 \
    -outform PEM \
    -keyout PkKek1.private.key \
    -out PkKek1.pem

  (where "PEM" simply means "DER + base64 + header + footer").

* Strip the header, footer, and newline characters; prepend the
  application prefix:

  sed \
    -e 's/^-----BEGIN CERTIFICATE-----$/4e32566d-8e9e-4f52-81d3-5bb9715f9727:/' \
    -e '/^-----END CERTIFICATE-----$/d' \
    PkKek1.pem \
  | tr -d '\n' \
  > PkKek1.oemstr

* Pass the certificate to EnrollDefaultKeys with the following QEMU
  option:

  -smbios type=11,value="$(< PkKek1.oemstr)"

  (Note: for the above option to work correctly, a QEMU version is needed
  that includes commit 950c4e6c94b1 ("opts: don't silently truncate long
  option values", 2018-05-09). The first upstream release with that commit
  was v3.0.0.

  Once <https://bugs.launchpad.net/qemu/+bug/1826200> is fixed, QEMU will
  learn to read the file directly; passing the blob on the command will be
  necessary no more.)

Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Julien Grall <julien.grall@arm.com>
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1747
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Gary Lin <glin@suse.com>