Re: [PATCH v5 7/8] machine/nitro-enclave: New machine type for AWS Nitro Enclaves

[Daniel P . Berrangé]

On Thu, Aug 22, 2024 at 09:08:48PM +0600, Dorjoy Chowdhury wrote:
> AWS nitro enclaves[1] is an Amazon EC2[2] 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 the 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.
> 
> An EIF (Enclave Image Format)[3] file is used to boot an AWS nitro enclave
> virtual machine. This commit adds support for AWS nitro enclave emulation
> using a new machine type option '-M nitro-enclave'. This new machine type
> is based on the 'microvm' machine type, similar to how real nitro enclave
> VMs are based on Firecracker microvm. For nitro-enclave to boot from an
> EIF file, the kernel and ramdisk(s) are extracted into a temporary kernel
> and a temporary initrd file which are then hooked into the regular x86
> boot mechanism along with the extracted cmdline. The EIF file path should
> be provided using the '-kernel' QEMU option.
> 
> In QEMU, the vsock emulation for nitro enclave is added using vhost-user-
> vsock as opposed to vhost-vsock. vhost-vsock doesn't support sibling VM
> communication which is needed for nitro enclaves. So for the vsock
> communication to CID 3 to work, another process that does the vsock
> emulation in  userspace must be run, for example, vhost-device-vsock[4]
> from rust-vmm, with necessary vsock communication support in another
> guest VM with CID 3. Using vhost-user-vsock also enables the possibility
> to implement some proxying support in the vhost-user-vsock daemon that
> will forward all the packets to the host machine instead of CID 3 so
> that users of nitro-enclave can run the necessary applications in their
> host machine instead of running another whole VM with CID 3. The following
> mandatory nitro-enclave machine option has been added related to the
> vhost-user-vsock device.
>   - 'vsock': The chardev id from the '-chardev' option for the
> vhost-user-vsock device.
> 
> AWS Nitro Enclaves have built-in Nitro Secure Module (NSM) device which
> has been added using the virtio-nsm device added in a previous commit.
> In Nitro Enclaves, all the PCRs start in a known zero state and the first
> 16 PCRs are locked from boot and reserved. The PCR0, PCR1, PCR2 and PCR8
> contain the SHA384 hashes related to the EIF file used to boot the VM
> for validation. The following optional nitro-enclave machine options
> have been added related to the NSM device.
>   - 'id': Enclave identifier, reflected in the module-id of the NSM
> device. If not provided, a default id will be set.
>   - 'parent-role': Parent instance IAM role ARN, reflected in PCR3
> of the NSM device.
>   - 'parent-id': Parent instance identifier, reflected in PCR4 of the
> NSM device.
> 
> [1] https://docs.aws.amazon.com/enclaves/latest/user/nitro-enclave.html
> [2] https://aws.amazon.com/ec2/
> [3] https://github.com/aws/aws-nitro-enclaves-image-format
> [4] https://github.com/rust-vmm/vhost-device/tree/main/vhost-device-vsock
> 
> Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
> ---
>  MAINTAINERS                              |   9 +
>  backends/hostmem-memfd.c                 |   2 -
>  configs/devices/i386-softmmu/default.mak |   1 +
>  hw/core/machine.c                        |  71 ++---
>  hw/core/meson.build                      |   3 +
>  hw/i386/Kconfig                          |   6 +
>  hw/i386/meson.build                      |   3 +
>  hw/i386/microvm.c                        |   6 +-
>  hw/i386/nitro_enclave.c                  | 355 +++++++++++++++++++++++
>  include/hw/boards.h                      |   2 +
>  include/hw/i386/microvm.h                |   2 +
>  include/hw/i386/nitro_enclave.h          |  62 ++++
>  include/sysemu/hostmem.h                 |   2 +
>  13 files changed, 488 insertions(+), 36 deletions(-)
>  create mode 100644 hw/i386/nitro_enclave.c
>  create mode 100644 include/hw/i386/nitro_enclave.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index da4f698137..aa7846107e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1877,6 +1877,15 @@ F: hw/i386/microvm.c
>  F: include/hw/i386/microvm.h
>  F: pc-bios/bios-microvm.bin
>  
> +nitro-enclave
> +M: Alexander Graf <graf@amazon.com>
> +M: Dorjoy Chowdhury <dorjoychy111@gmail.com>
> +S: Maintained
> +F: hw/core/eif.c
> +F: hw/core/eif.h

The eif.c/h files were added in the prevuous patch, so upto this line
should be added in the previous patch.

> +F: hw/i386/nitro_enclave.c
> +F: include/hw/i386/nitro_enclave.h

These two lines can remain in this patch

>  Machine core
>  M: Eduardo Habkost <eduardo@habkost.net>
>  M: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>


> diff --git a/hw/core/meson.build b/hw/core/meson.build
> index a3d9bab9f4..5437a94490 100644
> --- a/hw/core/meson.build
> +++ b/hw/core/meson.build
> @@ -24,6 +24,9 @@ system_ss.add(when: 'CONFIG_REGISTER', if_true: 
> files('register.c'))
>  system_ss.add(when: 'CONFIG_SPLIT_IRQ', if_true: files('split-irq.c'))
>  system_ss.add(when: 'CONFIG_XILINX_AXI', if_true: files('stream.c'))
>  system_ss.add(when: 'CONFIG_PLATFORM_BUS', if_true: files('sysbus-fdt.c'))
> +if libcbor.found() and gnutls.found()
> +  system_ss.add(when: 'CONFIG_NITRO_ENCLAVE', if_true: [files('eif.c'), 
> zlib, libcbor, gnutls])
> +endif
>  
>  system_ss.add(files(
>    'cpu-sysemu.c',


This change to meson.build should be in the previous patch, since
that's the one that introduces eif.c.

With regards,
Daniel
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