Stefano Garzarella
Stefano is a Principal Software Engineer at Red Hat. He is the maintainer of Linux's vsock subsystem (AF_VSOCK) and co-maintainer of rust-vmm. Current projects cover Confidential VMs, virtio devices, storage for VMs.
Session
The Coconut-SVSM is a platform to provide secure services to Confidential Virtual Machine guests. On AMD SEV-SNP, it runs inside the guest context at an elevated privilege level (VMPL).
SVSM is not yet able to preserve the state across reboots, so it provides services with limited functionality, such as a non-stateful virtual TPM for measured boot.
In this talk, we will describe the ongoing work towards stateful services, including a fully functional vTPM and a persistent and secure UEFI variable store, which can be employed for Secure Boot. This is achieved by adding encrypted persistent storage to the Coconut-SVSM, which is backed by the host hypervisor. The decryption key is received from the attestation server after a successful remote attestation during the early boot phase of the SVSM. The attestation covers the integrity of the platform, including SVSM and OVMF firmware. A host-side proxy is used to communicate with the server to keep the code in the SVSM context small.
During the talk we will look at the current challenges we are facing, potential attacks to defend against, and future developments to support a persistent state in SVSM.