Re: [libvirt PATCH v4 00/12] tools: provide virt-qemu-sev-validate for SEV(-ES) launch attestation

The libvirt QEMU driver provides all the functionality required for launching a guest on AMD SEV(-ES) platforms, with a configuration that enables attestation of the launch measurement. The documentation for how to actually perform an attestation is severely lacking and not suitable for mere mortals to understand. IOW, someone trying to implement attestation is in for a world of pain and suffering. This series doesn't fix the documentation problem, but it does provide a reference implementation of a tool for performing attestation of SEV(-ES) guests in the context of libvirt / KVM. There will be other tools and libraries that implement attestation logic too, but this tool is likely somewhat unique in its usage of libvirt. Now for a attestation to be trustworthy you don't want to perform it on the hypervisor host, since the goal is to prove that the hypervisor has not acted maliciously. None the less it is still beneficial to have libvirt integration to some extent. When running this tool on a remote (trusted) host, it can connect to the libvirt hypervisor and fetch the data provided by the virDomainLaunchSecurityInfo API, which is safe to trust as the key pieces are cryptographically measured. Attestation is a complex problem though and it is very easy to screw up and feed the wrong information and then waste hours trying to figure out what piece was wrong, to cause the hash digest to change. For debugging such problems, you can thus tell the tool to operate insecurely, by querying libvirt for almost all of the configuration information required to determine the expected measurement. By comparing these results,to the results obtained in offline mode it helps narrow down where the mistake lies. So I view this tool as being useful in a number of ways: * Quality assurance engineers needing to test libvirt/QEMU/KVM get a simple and reliable tool for automating tests with. * Users running simple libvirt deployments without any large management stack, get a standalone tool for attestation they can rely on. * Developers writing/integrating attestation support into management stacks above libvirt, get a reference against which they can debug their own tools. * Users wanting to demonstrate the core SEV/SEV-ES functionality get a simple and reliable tool to illustrate the core concepts involved. Since I didn't fancy writing such complex logic in C, this tool is a python3 program. As such, we don't want to include it in the main libvirt-client RPM, nor any other existing RPM. THus, this series puts it in a new libvirt-client-qemu RPM which, through no co-inicidence at all, is the same RPM I invented a few days ago to hold the virt-qemu-qmp-proxy command. Note, people will have already seen an earlier version of this tool I hacked up some months ago. This code is very significantly changed since that earlier version, to make it more maintainable, and simpler to use (especially for SEV-ES) but the general theme is still the same. Changed in v4: - Fixed loading of initrd/cmdline from XML - s/loader/firmware/ in some error messages Changed in v3: - Remove LUKS specific --disk-password and have generic --inject-secret - Fix handling of optional initrd/cmdline - Require --kernel if --initrd or --cmdline are present - Ensure VM is in paused state Changed in v2: - All the suggestions from Cole and Kashyap