Hi, Hope you are doing well. I am working on adding AWS Nitro Enclave[1] emulation support in QEMU. Alexander Graf is mentoring me on this work. A v1 patch series has already been posted to the qemu-devel mailing list[2].
AWS nitro enclaves is an Amazon EC2[3] feature that allows creating isolated execution environments, called enclaves, from Amazon EC2 instances, which are used for processing highly sensitive data. Enclaves have no persistent storage and no external networking. The enclave VMs are based on Firecracker microvm and have a vhost-vsock device for communication with the parent EC2 instance that spawned it and a Nitro Secure Module (NSM) device for cryptographic attestation. The parent instance VM always has CID 3 while the enclave VM gets a dynamic CID. The enclave VMs can communicate with the parent instance over various ports to CID 3, for example, the init process inside an enclave sends a heartbeat to port 9000 upon boot, expecting a heartbeat reply, letting the parent instance know that the enclave VM has successfully booted. The plan is to eventually make the nitro enclave emulation in QEMU standalone i.e., without needing to run another VM with CID 3 with proper vsock communication support. For this to work, one approach could be to teach the vhost driver in kernel to forward CID 3 messages to another CID N (set to CID 2 for host) i.e., it patches CID from 3 to N on incoming messages and from N to 3 on responses. This will enable users of the nitro-enclave machine type in QEMU to run the necessary vsock server/clients in the host machine (some defaults can be implemented in QEMU as well, for example, sending a reply to the heartbeat) which will rid them of the cumbersome way of running another whole VM with CID 3. This way, users of nitro-enclave machine in QEMU, could potentially also run multiple enclaves with their messages for CID 3 forwarded to different CIDs which, in QEMU side, could then be specified using a new machine type option (parent-cid) if implemented. I guess in the QEMU side, this will be an ioctl call (or some other way) to indicate to the host kernel that the CID 3 messages need to be forwarded. Does this approach of forwarding CID 3 messages to another CID sound good? If this approach sounds good, I need some guidance on where the code should be written in order to achieve this. I would greatly appreciate any suggestions. Thanks. Regards, Dorjoy [1] https://docs.aws.amazon.com/enclaves/latest/user/nitro-enclave.html [2] https://mail.gnu.org/archive/html/qemu-devel/2024-05/msg03524.html [3] https://aws.amazon.com/ec2/
