Re: [PATCH v2 00/18] Add support for Nitro Enclaves

Paraschiv, Andra-Irina
2020-05-22T06:40:19Z

On 22/05/2020 09:29, Andra Paraschiv wrote:
> Nitro Enclaves (NE) is a new Amazon Elastic Compute Cloud (EC2) capability
> that allows customers to carve out isolated compute environments within EC2
> instances [1].
>
> For example, an application that processes sensitive data and runs in a VM,
> can be separated from other applications running in the same VM. This
> application then runs in a separate VM than the primary VM, namely an enclave.
>
> An enclave runs alongside the VM that spawned it. This setup matches low latency
> applications needs. The resources that are allocated for the enclave, such as
> memory and CPU, are carved out of the primary VM. Each enclave is mapped to a
> process running in the primary VM, that communicates with the NE driver via an
> ioctl interface.
>
> In this sense, there are two components:
>
> 1. An enclave abstraction process - a user space process running in the primary
> VM guest that uses the provided ioctl interface of the NE driver to spawn an
> enclave VM (that's 2 below).
>
> How does all gets to an enclave VM running on the host?
>
> There is a NE emulated PCI device exposed to the primary VM. The driver for this
> new PCI device is included in the current patch series.
>
> The ioctl logic is mapped to PCI device commands e.g. the NE_START_ENCLAVE ioctl
> maps to an enclave start PCI command or the KVM_SET_USER_MEMORY_REGION maps to
> an add memory PCI command. The PCI device commands are then translated into
> actions taken on the hypervisor side; that's the Nitro hypervisor running on the
> host where the primary VM is running. The Nitro hypervisor is based on core KVM
> technology.
>
> 2. The enclave itself - a VM running on the same host as the primary VM that
> spawned it. Memory and CPUs are carved out of the primary VM and are dedicated
> for the enclave VM. An enclave does not have persistent storage attached.
>
> An enclave communicates with the primary VM via a local communication channel,
> using virtio-vsock [2]. The primary VM has virtio-pci vsock emulated device,
> while the enclave VM has a virtio-mmio vsock emulated device. The vsock device
> uses eventfd for signaling. The enclave VM sees the usual interfaces - local
> APIC and IOAPIC - to get interrupts from virtio-vsock device. The virtio-mmio
> device is placed in memory below the typical 4 GiB.
>
> The application that runs in the enclave needs to be packaged in an enclave
> image together with the OS ( e.g. kernel, ramdisk, init ) that will run in the
> enclave VM. The enclave VM has its own kernel and follows the standard Linux
> boot protocol.
>
> The kernel bzImage, the kernel command line, the ramdisk(s) are part of the
> Enclave Image Format (EIF); plus an EIF header including metadata such as magic
> number, eif version, image size and CRC.

Adding here that we've also considered FIT image format [1] as an option.

Andra

[1] https://github.com/u-boot/u-boot/tree/master/doc/uImage.FIT

>
> Hash values are computed for the entire enclave image (EIF), the kernel and
> ramdisk(s). That's used, for example, to check that the enclave image that is
> loaded in the enclave VM is the one that was intended to be run.
>
> These crypto measurements are included in a signed attestation document
> generated by the Nitro Hypervisor and further used to prove the identity of the
> enclave; KMS is an example of service that NE is integrated with and that checks
> the attestation doc.
>
> The enclave image (EIF) is loaded in the enclave memory at offset 8 MiB. The
> init process in the enclave connects to the vsock CID of the primary VM and a
> predefined port - 9000 - to send a heartbeat value - 0xb7. This mechanism is
> used to check in the primary VM that the enclave has booted.
>
> If the enclave VM crashes or gracefully exits, an interrupt event is received by
> the NE driver. This event is sent further to the user space enclave process
> running in the primary VM via a poll notification mechanism. Then the user space
> enclave process can exit.
>
> The following patch series covers the NE driver for enclave lifetime management.
> It provides an ioctl interface to the user space and includes the NE PCI device
> driver that is the means of communication with the hypervisor running on the
> host where the primary VM and the enclave are launched.
>
> The proposed solution is following the KVM model and uses KVM ioctls to be able
> to create and set resources for enclaves. Additional NE ioctl commands, besides
> the ones provided by KVM, are used to start an enclave and get memory offset for
> in-memory enclave image loading.
>
> Thank you.
>
> Andra
>
> [1] https://aws.amazon.com/ec2/nitro/nitro-enclaves/
> [2] http://man7.org/linux/man-pages/man7/vsock.7.html
>
> ---
>
> Patch Series Changelog
>
> The patch series is built on top of v5.7-rc6.
>
> v1 -> v2
>
> * Rebase on top of v5.7-rc6.
> * Adapt codebase based on feedback from v1.
> * Update ioctl number definition - major and minor.
> * Add sample / documentation for the ioctl interface basic flow usage.
> * Update cover letter to include more context on the NE overall.
> * Add fix for the enclave / vcpu fd creation error cleanup path.
> * Add fix reported by kbuild test robot <lkp@intel.com>.
> * v1: https://lore.kernel.org/lkml/20200421184150.68011-1-andraprs@amazon.com/
>
> ---
>
> Andra Paraschiv (18):
> nitro_enclaves: Add ioctl interface definition
> nitro_enclaves: Define the PCI device interface
> nitro_enclaves: Define enclave info for internal bookkeeping
> nitro_enclaves: Init PCI device driver
> nitro_enclaves: Handle PCI device command requests
> nitro_enclaves: Handle out-of-band PCI device events
> nitro_enclaves: Init misc device providing the ioctl interface
> nitro_enclaves: Add logic for enclave vm creation
> nitro_enclaves: Add logic for enclave vcpu creation
> nitro_enclaves: Add logic for enclave image load metadata
> nitro_enclaves: Add logic for enclave memory region set
> nitro_enclaves: Add logic for enclave start
> nitro_enclaves: Add logic for enclave termination
> nitro_enclaves: Add Kconfig for the Nitro Enclaves driver
> nitro_enclaves: Add Makefile for the Nitro Enclaves driver
> nitro_enclaves: Add sample for ioctl interface usage
> nitro_enclaves: Add overview documentation
> MAINTAINERS: Add entry for the Nitro Enclaves driver
>
> Documentation/nitro_enclaves/ne_overview.txt | 86 ++
> .../userspace-api/ioctl/ioctl-number.rst | 5 +-
> MAINTAINERS | 13 +
> drivers/virt/Kconfig | 2 +
> drivers/virt/Makefile | 2 +
> drivers/virt/nitro_enclaves/Kconfig | 28 +
> drivers/virt/nitro_enclaves/Makefile | 23 +
> drivers/virt/nitro_enclaves/ne_misc_dev.c | 1152 +++++++++++++++++
> drivers/virt/nitro_enclaves/ne_misc_dev.h | 121 ++
> drivers/virt/nitro_enclaves/ne_pci_dev.c | 717 ++++++++++
> drivers/virt/nitro_enclaves/ne_pci_dev.h | 266 ++++
> include/linux/nitro_enclaves.h | 23 +
> include/uapi/linux/nitro_enclaves.h | 77 ++
> samples/nitro_enclaves/.gitignore | 2 +
> samples/nitro_enclaves/Makefile | 28 +
> .../include/linux/nitro_enclaves.h | 23 +
> .../include/uapi/linux/nitro_enclaves.h | 77 ++
> samples/nitro_enclaves/ne_ioctl_sample.c | 502 +++++++
> 18 files changed, 3146 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/nitro_enclaves/ne_overview.txt
> create mode 100644 drivers/virt/nitro_enclaves/Kconfig
> create mode 100644 drivers/virt/nitro_enclaves/Makefile
> create mode 100644 drivers/virt/nitro_enclaves/ne_misc_dev.c
> create mode 100644 drivers/virt/nitro_enclaves/ne_misc_dev.h
> create mode 100644 drivers/virt/nitro_enclaves/ne_pci_dev.c
> create mode 100644 drivers/virt/nitro_enclaves/ne_pci_dev.h
> create mode 100644 include/linux/nitro_enclaves.h
> create mode 100644 include/uapi/linux/nitro_enclaves.h
> create mode 100644 samples/nitro_enclaves/.gitignore
> create mode 100644 samples/nitro_enclaves/Makefile
> create mode 100644 samples/nitro_enclaves/include/linux/nitro_enclaves.h
> create mode 100644 samples/nitro_enclaves/include/uapi/linux/nitro_enclaves.h
> create mode 100644 samples/nitro_enclaves/ne_ioctl_sample.c
>