From patchwork Mon Aug 17 13:10:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paraschiv, Andra-Irina" X-Patchwork-Id: 11718237 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2C382618 for ; Mon, 17 Aug 2020 13:14:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1242F2076E for ; Mon, 17 Aug 2020 13:14:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="W3SWtXbc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728676AbgHQNOQ (ORCPT ); Mon, 17 Aug 2020 09:14:16 -0400 Received: from smtp-fw-6001.amazon.com ([52.95.48.154]:27796 "EHLO smtp-fw-6001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728819AbgHQNNS (ORCPT ); Mon, 17 Aug 2020 09:13:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1597669998; x=1629205998; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3wCnCkfoS6eWoqMLxN1SWV/HlSl8sbP9wEv/BoEIfFQ=; b=W3SWtXbcJpsS8mCEIbtJZUE4bpnqIPbJH/isplbrsHFPnALIsdMr1/um y2okebwG7d7OcO1QZ/75qm3wTnm9qm7/5MRsKNaUT0etF41nqIZA6FJpY n5dN8563w6hCz/VhF35DpIxltZyKEl6l9ftPtzDeX2jMvmjjiA9e7MwYz k=; X-IronPort-AV: E=Sophos;i="5.76,322,1592870400"; d="scan'208";a="49637923" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-2b-4ff6265a.us-west-2.amazon.com) ([10.43.8.6]) by smtp-border-fw-out-6001.iad6.amazon.com with ESMTP; 17 Aug 2020 13:13:16 +0000 Received: from EX13MTAUEA001.ant.amazon.com (pdx4-ws-svc-p6-lb7-vlan3.pdx.amazon.com [10.170.41.166]) by email-inbound-relay-2b-4ff6265a.us-west-2.amazon.com (Postfix) with ESMTPS id 1E625A229F; Mon, 17 Aug 2020 13:13:15 +0000 (UTC) Received: from EX13D16EUB001.ant.amazon.com (10.43.166.28) by EX13MTAUEA001.ant.amazon.com (10.43.61.82) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 17 Aug 2020 13:13:13 +0000 Received: from 38f9d34ed3b1.ant.amazon.com (10.43.161.85) by EX13D16EUB001.ant.amazon.com (10.43.166.28) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 17 Aug 2020 13:13:04 +0000 From: Andra Paraschiv To: linux-kernel CC: Anthony Liguori , Benjamin Herrenschmidt , Colm MacCarthaigh , "David Duncan" , Bjoern Doebel , "David Woodhouse" , Frank van der Linden , Alexander Graf , Greg KH , "Karen Noel" , Martin Pohlack , Matt Wilson , Paolo Bonzini , Balbir Singh , Stefano Garzarella , "Stefan Hajnoczi" , Stewart Smith , "Uwe Dannowski" , Vitaly Kuznetsov , kvm , ne-devel-upstream , Andra Paraschiv Subject: [PATCH v7 17/18] nitro_enclaves: Add overview documentation Date: Mon, 17 Aug 2020 16:10:02 +0300 Message-ID: <20200817131003.56650-18-andraprs@amazon.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20200817131003.56650-1-andraprs@amazon.com> References: <20200817131003.56650-1-andraprs@amazon.com> MIME-Version: 1.0 X-Originating-IP: [10.43.161.85] X-ClientProxiedBy: EX13D03UWA001.ant.amazon.com (10.43.160.141) To EX13D16EUB001.ant.amazon.com (10.43.166.28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Signed-off-by: Andra Paraschiv --- Changelog v6 -> v7 * No changes. v5 -> v6 * No changes. v4 -> v5 * No changes. v3 -> v4 * Update doc type from .txt to .rst. * Update documentation based on the changes from v4. v2 -> v3 * No changes. v1 -> v2 * New in v2. --- Documentation/nitro_enclaves/ne_overview.rst | 87 ++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 Documentation/nitro_enclaves/ne_overview.rst diff --git a/Documentation/nitro_enclaves/ne_overview.rst b/Documentation/nitro_enclaves/ne_overview.rst new file mode 100644 index 000000000000..9cc7a2720955 --- /dev/null +++ b/Documentation/nitro_enclaves/ne_overview.rst @@ -0,0 +1,87 @@ +Nitro Enclaves +============== + +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 CPUs, 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). + +There is a NE emulated PCI device exposed to the primary VM. The driver for this +new PCI device is included in the NE driver. + +The ioctl logic is mapped to PCI device commands e.g. the NE_START_ENCLAVE ioctl +maps to an enclave start 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. + +The memory regions carved out of the primary VM and given to an enclave need to +be aligned 2 MiB / 1 GiB physically contiguous memory regions (or multiple of +this size e.g. 8 MiB). The memory can be allocated e.g. by using hugetlbfs from +user space [2][3]. The memory size for an enclave needs to be at least 64 MiB. +The enclave memory and CPUs need to be from the same NUMA node. + +An enclave runs on dedicated cores. CPU 0 and its CPU siblings need to remain +available for the primary VM. A CPU pool has to be set for NE purposes by an +user with admin capability. See the cpu list section from the kernel +documentation [4] for how a CPU pool format looks. + +An enclave communicates with the primary VM via a local communication channel, +using virtio-vsock [5]. 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. + +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. + +[1] https://aws.amazon.com/ec2/nitro/nitro-enclaves/ +[2] https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt +[3] https://lwn.net/Articles/807108/ +[4] https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html +[5] https://man7.org/linux/man-pages/man7/vsock.7.html