Add support for running Confidential Workloads with AMD SEV #36
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In the regular version of libkrun, the integrated VMM starts booting directly in 64 bits and into the kernel entry point, after setting up some initial data structures (page tables, e820, mptables...). With SEV, those data structures are problem, as they become part of the launch measurement. So, if targeting SEV, use qboot as firmware, loading it into the reset, and don't set those initial data structures (they'll be set by qboot after the VM is started). This commit also introduces the "amd-sev" feature to allow users to choose this flavor or the library. Signed-off-by: Sergio Lopez <slp@redhat.com>
Linux on SEV requires MTRR and PAT, so enable and configure the MSR for MTRRdefType. Signed-off-by: Sergio Lopez <slp@redhat.com>
Introduce initial plain SEV support. This sets the stage for adding remote attestation, SEV-ES and SEV-SNP in the future. This functionality is gated behind the "amd-sev" feature defined in the workspace's Cargo. In practice, this means now libkrun comes in two different flavors, regular libkrun (for container isolation) and SEV-enabled libkrun (for Confidential Computing). Signed-off-by: Sergio Lopez <slp@redhat.com>
Import virtio-block support from Firecraker, and use it to replace virtio-fs in the SEV flavor. Extend the API with the "krun_set_root_disk()" function to allow users to configure the disk image that contains the root filesystem. While there, disable also virtio-balloon when targeting libkrun-SEV. Signed-off-by: Sergio Lopez <slp@redhat.com>
With virtio-fs gone, we need a trusted place to put the "init" binary that sets up the environment in the guest for running the workload entry point and, in case of using LUKS, to unlock the root file system. The obvious replacement is using an initramfs. This change extends libkrun to load the initrd bundled in the SEV variant of libkrunfw. Signed-off-by: Sergio Lopez <slp@redhat.com>
If the KRUN_PASS environment variable is present, use cryptsetup to open a LUKS volume in "/dev/vda" and, if successful, mount it and switch to it as root file system. Signed-off-by: Sergio Lopez <slp@redhat.com>
Implement support for Remote Attestation using a simple custom protocol over HTTP, serializing and deserializing SEV-related data structures as JSON objects. This also adds the "krun_set_attestation_url()" function to the API (only for libkrun-SEV), to enable users set up the base URL for the attestation server. If missing, libkrun-SEV will still encrypt the guest's memory, but it's initial contents won't be attested. Signed-off-by: Sergio Lopez <slp@redhat.com>
Detect AMD CPU model (from the SEV supported range) and use it to download the ASK/ARK certificate. Signed-off-by: Sergio Lopez <slp@redhat.com>
Add the examples "sev-attest" and "sev-noattest" to test the SEV
functionality.
The first one ("sev-attest") enables SEV and does remote attestation,
receiving the LUKS passphrase and the rest of the command line (which
includes the workload entry point) from the remote attestation server
in pre-encrypted form, so it can be safely injected into the guest
memory by the VMM.
The other ("sev-noattest") also enables SEV (and thus, memory
encryption), but doesn't attempt to do a remote attestation, and as a
consequence, both the LUKS passphrase and the command line are passed
in plain text through the VMM.
Signed-off-by: Sergio Lopez <slp@redhat.com>
Add the SEV flag to Makefile and examples/Makefile, to allow users to easily opt-in to build the SEV flavor of both libkrun and the examples by passing "SEV=1" to "make". Signed-off-by: Sergio Lopez <slp@redhat.com>
Increase the RAM of the SEV examples (sev-attest and sev-noattest) from 512 MiB to 2 GiB, so cryptsetup is able to open LUKS2 volumes. Signed-off-by: Sergio Lopez <slp@redhat.com>
kvm_bindings::CpuId API has changed slightly, update related code. Signed-off-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Sergio Lopez <slp@redhat.com>
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