From patchwork Mon Apr 24 23:15:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elliot Berman X-Patchwork-Id: 677304 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A746EC77B7E for ; Mon, 24 Apr 2023 23:16:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232681AbjDXXQt (ORCPT ); Mon, 24 Apr 2023 19:16:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229755AbjDXXQp (ORCPT ); Mon, 24 Apr 2023 19:16:45 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E00793E8; Mon, 24 Apr 2023 16:16:43 -0700 (PDT) Received: from pps.filterd (m0279872.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 33OMqccU027417; Mon, 24 Apr 2023 23:16:30 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=qcppdkim1; bh=C6x+ezs5oIrgdvXKUCXjeMXzDUB4EKTwEYqtVCN2ZSM=; b=FrQtgEVI3r4C/95kV5BmkZ6J1wgol69SSsu7MUm2Cu+wf6FTUXTxXQvwZWeIHGK0fgEm dIwldo6L9ERqic4oULA3I+Qi/UB4OV2KWVMVVjjh64HXi5OgZJr61btUwU4mQZH6o64Y wBzg6MDI2q2beKu0SoZCpbOOlDoudTjrcrLsl0fIvca/sCZ0Eo8KPH3BdCEmx+qozC1U WM1sr9dzWan45IIus1row/MlQ1y8C1EMQYLTVMNYNUhzRfB2e1KzQfLYjhSfKccT6xYO OTwdrMz4/80oj/3u+0ZHViBtdbDgBrw6YJLHj63JcRP4A4S70rXI0WsSI8bjPSw589b7 PA== Received: from nasanppmta04.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3q5r0uskme-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 24 Apr 2023 23:16:29 +0000 Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 33ONGSaS006868 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 24 Apr 2023 23:16:28 GMT Received: from hu-eberman-lv.qualcomm.com (10.49.16.6) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Mon, 24 Apr 2023 16:16:27 -0700 From: Elliot Berman To: Alex Elder , Srinivas Kandagatla , Elliot Berman , Prakruthi Deepak Heragu , Jonathan Corbet CC: Murali Nalajala , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Dmitry Baryshkov , Bjorn Andersson , "Konrad Dybcio" , Arnd Bergmann , "Greg Kroah-Hartman" , Rob Herring , Krzysztof Kozlowski , Bagas Sanjaya , Will Deacon , Andy Gross , Catalin Marinas , Jassi Brar , , , , , Subject: [PATCH v12 01/25] docs: gunyah: Introduce Gunyah Hypervisor Date: Mon, 24 Apr 2023 16:15:34 -0700 Message-ID: <20230424231558.70911-2-quic_eberman@quicinc.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424231558.70911-1-quic_eberman@quicinc.com> References: <20230424231558.70911-1-quic_eberman@quicinc.com> MIME-Version: 1.0 X-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01a.na.qualcomm.com (10.47.209.196) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: 7ZfKVPC2_ApCkI7lct8pkBoUiwbRS7lx X-Proofpoint-ORIG-GUID: 7ZfKVPC2_ApCkI7lct8pkBoUiwbRS7lx X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22 definitions=2023-04-24_11,2023-04-21_01,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 adultscore=0 mlxlogscore=999 phishscore=0 mlxscore=0 spamscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 lowpriorityscore=0 clxscore=1011 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2303200000 definitions=main-2304240211 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Gunyah is an open-source Type-1 hypervisor developed by Qualcomm. It does not depend on any lower-privileged OS/kernel code for its core functionality. This increases its security and can support a smaller trusted computing based when compared to Type-2 hypervisors. Add documentation describing the Gunyah hypervisor and the main components of the Gunyah hypervisor which are of interest to Linux virtualization development. Reviewed-by: Bagas Sanjaya Signed-off-by: Elliot Berman --- Documentation/virt/gunyah/index.rst | 113 ++++++++++++++++++++ Documentation/virt/gunyah/message-queue.rst | 63 +++++++++++ Documentation/virt/index.rst | 1 + 3 files changed, 177 insertions(+) create mode 100644 Documentation/virt/gunyah/index.rst create mode 100644 Documentation/virt/gunyah/message-queue.rst diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst new file mode 100644 index 000000000000..74aa345e0a14 --- /dev/null +++ b/Documentation/virt/gunyah/index.rst @@ -0,0 +1,113 @@ +.. SPDX-License-Identifier: GPL-2.0 + +================= +Gunyah Hypervisor +================= + +.. toctree:: + :maxdepth: 1 + + message-queue + +Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in +a higher CPU privilege level. It does not depend on any lower-privileged operating system +for its core functionality. This increases its security and can support a much smaller +trusted computing base than a Type-2 hypervisor. + +Gunyah is an open source hypervisor. The source repo is available at +https://github.com/quic/gunyah-hypervisor. + +Gunyah provides these following features. + +- Scheduling: + + A scheduler for virtual CPUs (vCPUs) on physical CPUs enables time-sharing + of the CPUs. Gunyah supports two models of scheduling: + + 1. "Behind the back" scheduling in which Gunyah hypervisor schedules vCPUS on its own. + 2. "Proxy" scheduling in which a delegated VM can donate part of one of its vCPU slice + to another VM's vCPU via a hypercall. + +- Memory Management: + + APIs handling memory, abstracted as objects, limiting direct use of physical + addresses. Memory ownership and usage tracking of all memory under its control. + Memory partitioning between VMs is a fundamental security feature. + +- Interrupt Virtualization: + + Uses CPU hardware interrupt virtualization capabilities. Interrupts are handled + in the hypervisor and routed to the assigned VM. + +- Inter-VM Communication: + + There are several different mechanisms provided for communicating between VMs. + +- Virtual platform: + + Architectural devices such as interrupt controllers and CPU timers are directly provided + by the hypervisor as well as core virtual platform devices and system APIs such as ARM PSCI. + +- Device Virtualization: + + Para-virtualization of devices is supported using inter-VM communication. + +Architectures supported +======================= +AArch64 with a GIC + +Resources and Capabilities +========================== + +Some services or resources provided by the Gunyah hypervisor are described to a virtual machine by +capability IDs. For instance, inter-VM communication is performed with doorbells and message queues. +Gunyah allows access to manipulate that doorbell via the capability ID. These resources are +described in Linux as a struct gh_resource. + +High level management of these resources is performed by the resource manager VM. RM informs a +guest VM about resources it can access through either the device tree or via guest-initiated RPC. + +For each virtual machine, Gunyah maintains a table of resources which can be accessed by that VM. +An entry in this table is called a "capability" and VMs can only access resources via this +capability table. Hence, virtual Gunyah resources are referenced by a "capability IDs" and not +"resource IDs". If 2 VMs have access to the same resource, they might not be using the same +capability ID to access that resource since the capability tables are independent per VM. + +Resource Manager +================ + +The resource manager (RM) is a privileged application VM supporting the Gunyah Hypervisor. +It provides policy enforcement aspects of the virtualization system. The resource manager can +be treated as an extension of the Hypervisor but is separated to its own partition to ensure +that the hypervisor layer itself remains small and secure and to maintain a separation of policy +and mechanism in the platform. RM runs at arm64 NS-EL1 similar to other virtual machines. + +Communication with the resource manager from each guest VM happens with message-queue.rst. Details +about the specific messages can be found in drivers/virt/gunyah/rsc_mgr.c + +:: + + +-------+ +--------+ +--------+ + | RM | | VM_A | | VM_B | + +-.-.-.-+ +---.----+ +---.----+ + | | | | + +-.-.-----------.------------.----+ + | | \==========/ | | + | \========================/ | + | Gunyah | + +---------------------------------+ + +The source for the resource manager is available at https://github.com/quic/gunyah-resource-manager. + +The resource manager provides the following features: + +- VM lifecycle management: allocating a VM, starting VMs, destruction of VMs +- VM access control policy, including memory sharing and lending +- Interrupt routing configuration +- Forwarding of system-level events (e.g. VM shutdown) to owner VM + +When booting a virtual machine which uses a devicetree such as Linux, resource manager overlays a +/hypervisor node. This node can let Linux know it is running as a Gunyah guest VM, +how to communicate with resource manager, and basic description and capabilities of +this VM. See Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml for a description +of this node. diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst new file mode 100644 index 000000000000..b352918ae54b --- /dev/null +++ b/Documentation/virt/gunyah/message-queue.rst @@ -0,0 +1,63 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Message Queues +============== +Message queue is a simple low-capacity IPC channel between two VMs. It is +intended for sending small control and configuration messages. Each message +queue is unidirectional, so a full-duplex IPC channel requires a pair of queues. + +Messages can be up to 240 bytes in length. Longer messages require a further +protocol on top of the message queue messages themselves. For instance, communication +with the resource manager adds a header field for sending longer messages via multiple +message fragments. + +The diagram below shows how message queue works. A typical configuration involves +2 message queues. Message queue 1 allows VM_A to send messages to VM_B. Message +queue 2 allows VM_B to send messages to VM_A. + +1. VM_A sends a message of up to 240 bytes in length. It raises a hypercall + with the message to inform the hypervisor to add the message to + message queue 1's queue. The hypervisor copies memory into the internal + message queue representation; the memory doesn't need to be shared between + VM_A and VM_B. + +2. Gunyah raises the corresponding interrupt for VM_B (Rx vIRQ) when any of + these happens: + + a. gh_msgq_send() has PUSH flag. Queue is immediately flushed. This is the typical case. + b. Explicility with gh_msgq_push command from VM_A. + c. Message queue has reached a threshold depth. + +3. VM_B calls gh_msgq_recv() and Gunyah copies message to requested buffer. + +4. Gunyah buffers messages in the queue. If the queue became full when VM_A added a message, + the return values for gh_msgq_send() include a flag that indicates the queue is full. + Once VM_B receives the message and, thus, there is space in the queue, Gunyah + will raise the Tx vIRQ on VM_A to indicate it can continue sending messages. + +For VM_B to send a message to VM_A, the process is identical, except that hypercalls +reference message queue 2's capability ID. Each message queue has its own independent +vIRQ: two TX message queues will have two vIRQs (and two capability IDs). + +:: + + +---------------+ +-----------------+ +---------------+ + | VM_A | |Gunyah hypervisor| | VM_B | + | | | | | | + | | | | | | + | | Tx | | | | + | |-------->| | Rx vIRQ | | + |gh_msgq_send() | Tx vIRQ |Message queue 1 |-------->|gh_msgq_recv() | + | |<------- | | | | + | | | | | | + | Message Queue | | | | Message Queue | + | driver | | | | driver | + | | | | | | + | | | | | | + | | | | Tx | | + | | Rx vIRQ | |<--------| | + |gh_msgq_recv() |<--------|Message queue 2 | Tx vIRQ |gh_msgq_send() | + | | | |-------->| | + | | | | | | + | | | | | | + +---------------+ +-----------------+ +---------------+ diff --git a/Documentation/virt/index.rst b/Documentation/virt/index.rst index 7fb55ae08598..15869ee059b3 100644 --- a/Documentation/virt/index.rst +++ b/Documentation/virt/index.rst @@ -16,6 +16,7 @@ Virtualization Support coco/sev-guest coco/tdx-guest hyperv/index + gunyah/index .. only:: html and subproject