--- docs/system/i386/nitro-enclave.rst | 82 ++++++++++++++++++++++++++++++ 1 file changed, 82 insertions(+) create mode 100644 docs/system/i386/nitro-enclave.rst
diff --git a/docs/system/i386/nitro-enclave.rst b/docs/system/i386/nitro-enclave.rst new file mode 100644 index 0000000000..291a8ae357 --- /dev/null +++ b/docs/system/i386/nitro-enclave.rst @@ -0,0 +1,82 @@ +'nitro-enclave' virtual machine (``nitro-enclave``) +=================================================== + +``nitro-enclave`` is a machine type which emulates an ``AWS nitro enclave`` +virtual machine. `AWS nitro enclaves`_ is an `Amazon EC2`_ 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 with 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. Enclaves use an EIF (`Enclave Image Format`_) +file which contains the necessary kernel, cmdline and ramdisk(s) to boot. + +In QEMU, ``nitro-enclave`` is a machine type based on ``microvm`` similar to how +``AWS nitro enclaves`` are based on ``Firecracker`` microvm. This is useful for +local testing of EIF files using QEMU instead of running real AWS Nitro Enclaves +which can be difficult for debugging due to its roots in security. The vsock +device emulation is done using vhost-user-vsock which means another process that +can do the userspace emulation, like `vhost-device-vsock`_ from rust-vmm crate, +must be run alongside nitro-enclave for the vsock communication to work. + +.. _AWS nitro enlaves: https://docs.aws.amazon.com/enclaves/latest/user/nitro-enclave.html +.. _Amazon EC2: https://aws.amazon.com/ec2/ +.. _Enclave Image Format: https://github.com/aws/aws-nitro-enclaves-image-format +.. _vhost-device-vsock: https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock + +Using the nitro-enclave machine type +------------------------------ + +Machine-specific options +~~~~~~~~~~~~~~~~~~~~~~~~ + +It supports the following machine-specific options: + +- nitro-enclave.vsock=string (required) (Id of the chardev from '-chardev' option that vhost-user-vsock device will use) +- nitro-enclave.id=string (optional) (Set enclave identifier) +- nitro-enclave.parent-role=string (optional) (Set parent instance IAM role ARN) +- nitro-enclave.parent-id=string (optional) (Set parent instance identifier) + + +Running a nitro-enclave VM +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +First, run vhost-device-vsock (or a similar tool that supports vhost-user-vsock) + + $ vhost-device-vsock \ + --vm guest-cid=4,uds-path=/tmp/vm4.vsock,socket=/tmp/vhost4.socket \ + --vm guest-cid=3,uds-path=/tmp/vm3.vsock,socket=/tmp/vhost3.socket + +Then, run the parent VM that has the necessary vsock communication support. + + $ qemu-system-x86_64 -machine q35,memory-backend=mem0 -enable-kvm -m 8G \ + -nic user,model=virtio -drive file=test_vm.qcow2,media=disk,if=virtio \ + --display sdl -object memory-backend-memfd,id=mem0,size=8G \ + -chardev socket,id=char0,reconnect=0,path=/tmp/vhost3.socket \ + -device vhost-user-vsock-pci,chardev=char0 + +Inside this VM the necessary applications should be run so that the nitro-enclave +VM applications' vsock communication works. For example, the nitro-enclave VM's +init process connects to CID 3 and sends a single byte hello heartbeat (0xB7) to +let the parent VM know that it booted expecting a heartbeat (0xB7) response. + +Now run the nitro-enclave VM using the following command where ``hello.eif`` is +an EIF file you would use to spawn a real AWS nitro enclave virtual machine: + + $ qemu-system-x86_64 -M nitro-enclave,vsock=c,id=hello-world \ + -kernel hello-world.eif -nographic -m 4G --enable-kvm -cpu host \ + -chardev socket,id=c,path=/tmp/vhost4.socket + +In this example, the nitro-enclave VM has CID 4. + + +Limitations +----------- + +AWS nitro enclave emulation support in QEMU requires users to run vhost-device-vsock +or similar tool for vhost-user-vsock support and another VM with CID 3 with necessary +vsock communication support. Requirement of running another VM and necessary applications +inside it can be lifted if some proxying support is added to vhost-device-vsock to +forward all packets to the host machine, in which case, users can run the necessary +applications in the host machine instead of the parent VM with CID 3. -- 2.39.2
