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The current firmware descriptor schema for flash requires that both the executable to NVRAM template paths be provided. This is fine for the most common usage of EDK2 builds in virtualization where the separate _CODE and _VARS files are provided. With confidential computing technology like AMD SEV, persistent storage of variables may be completely disabled because the firmware requires a known clean state on every cold boot. There is no way to express this in the firmware descriptor today. Even with regular EDK2 builds it is possible to create a firmware that has both executable code and variable persistence in a single file. This hasn't been commonly used, since it would mean every guest bootup would need to clone the full firmware file, leading to redundant duplicate storage of the code portion. In some scenarios this may not matter and might even be beneficial. For example if a public cloud allows users to bring their own firmware, such that the user can pre-enroll their own secure boot keys, you're going to have this copied on disk for each tenant already. At this point the it can be simpler to just deal with a single file rather than split builds. The firmware descriptor ought to be able to express this combined firmware model too. This all points towards expanding the schema for flash with a 'mode' concept: - "split" - the current implicit behaviour with separate files for code and variables. - "combined" - the alternate behaviour where a single file contains both code and variables. - "stateless" - the confidential computing use case where storage of variables is completely disable, leaving only the code. Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> |
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| .. | ||
| barrier.rst | ||
| bitmaps.rst | ||
| dbus-display.rst | ||
| dbus-vmstate.rst | ||
| dbus.rst | ||
| firmware.json | ||
| index.rst | ||
| live-block-operations.rst | ||
| nbd.txt | ||
| parallels.txt | ||
| pr-helper.rst | ||
| prl-xml.txt | ||
| qcow2.txt | ||
| qed_spec.txt | ||
| qemu-ga-ref.rst | ||
| qemu-ga.rst | ||
| qemu-qmp-ref.rst | ||
| qemu-storage-daemon-qmp-ref.rst | ||
| qmp-intro.txt | ||
| qmp-spec.txt | ||
| vhost-user-gpu.rst | ||
| vhost-user.json | ||
| vhost-user.rst | ||
| vhost-vdpa.rst | ||
| virtio-balloon-stats.rst | ||
| vnc-ledstate-Pseudo-encoding.txt | ||