Re: [RFC PATCH v2 0/2] i386/sev: Support measured direct kernel boot on SNP

[Dov Murik]

On 16/02/2023 10:49, Dov Murik wrote:
> This RFC patch series is based on AMD's RFC upmv10-snpv3 tree [1].
> 

Note that in order to test this you must use '-machine pc-q35-7.1'
to circumvent the SETUP_RNG_SEED bug [1] that interferes with the
measured kernel.

[1] 20230208211212.41951-1-mst@redhat.com/">https://lore.kernel.org/qemu-devel/20230208211212.41951-1-mst@redhat.com/


-Dov


> 
> In order to enable measured direct kernel boot on SNP, QEMU needs to
> fill the hashes page when kernel-hashes=on.  This relies on several
> changes to the SNP metadata published by OVMF (See [2] for proposed
> OVMF patches).
> 
> Patch 1 pulls the 'kernel-hashes' property from the SEV guest settings
> to the common settings to make it available for both SEV and SNP.
> 
> Patch 2 adds the hashes table for SNP guests (or validates the page as a
> zero page if kernel-hashes=off).
> 
> This patch series is also available at [3].
> 
> 
> [1] https://github.com/mdroth/qemu/commits/upmv10-snpv3
> [2] https://edk2.groups.io/g/devel/message/100286
> [3] 
> https://github.com/confidential-containers-demo/qemu/tree/snp-kernel-hashes-v2
> 
> v2 changes:
> * Rebase on top of upmv10-snpv3 which includes kernel-hashes.
> 
> v1: 
> https://lore.kernel.org/qemu-devel/20220329064038.96006-1-dovmurik%40linux.ibm.com/
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Daniel P. Berrangé <berrange@redhat.com>
> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Cc: Eduardo Habkost <eduardo@habkost.net>
> Cc: Eric Blake <eblake@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> Cc: Marcelo Tosatti <mtosatti@redhat.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: James Bottomley <jejb@linux.ibm.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: Michael Roth <michael.roth@amd.com>
> Cc: Ashish Kalra <ashish.kalra@amd.com>
> Cc: Mario Smarduch <mario.smarduch@amd.com>
> Cc: Tobin Feldman-Fitzthum <tobin@linux.ibm.com>
> 
> Dov Murik (2):
>   qapi, i386: Move kernel-hashes to SevCommonProperties
>   i386/sev: Allow measured direct kernel boot on SNP
> 
>  qapi/qom.json     | 12 +++---
>  target/i386/sev.c | 95 +++++++++++++++++++++++++++++------------------
>  2 files changed, 65 insertions(+), 42 deletions(-)
>