From: Bagas Sanjaya <bagasdotme@gmail.com>
To: Elliot Berman <quic_eberman@quicinc.com>
Cc: Bjorn Andersson <quic_bjorande@quicinc.com>,
Jonathan Corbet <corbet@lwn.net>,
Murali Nalajala <quic_mnalajal@quicinc.com>,
Trilok Soni <quic_tsoni@quicinc.com>,
Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>,
Carl van Schaik <quic_cvanscha@quicinc.com>,
Andy Gross <agross@kernel.org>,
Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
Jassi Brar <jassisinghbrar@gmail.com>,
linux-arm-kernel@lists.infradead.org,
Mark Rutland <mark.rutland@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Marc Zyngier <maz@kernel.org>, Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Arnd Bergmann <arnd@arndb.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 01/14] docs: gunyah: Introduce Gunyah Hypervisor
Date: Thu, 29 Sep 2022 10:43:36 +0700 [thread overview]
Message-ID: <YzUUaIx+azyzFDNX@debian.me> (raw)
In-Reply-To: <20220928195633.2348848-2-quic_eberman@quicinc.com>
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On Wed, Sep 28, 2022 at 12:56:20PM -0700, Elliot Berman wrote:
> diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
> new file mode 100644
> index 000000000000..959f451caccd
> --- /dev/null
> +++ b/Documentation/virt/gunyah/index.rst
> @@ -0,0 +1,114 @@
> +.. 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 and 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 devices are described
> +in Linux as a struct gunyah_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 devices are referenced by a "capability IDs" and not a
> +"resource IDs". A VM can have multiple capability IDs mapping to the same resource. If 2 VMs have
> +access to the same resource, they may not be using the same capability ID to access that resource
> +since the 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. On arm64, RM runs at 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, 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.
The documentation LGTM.
> diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
> new file mode 100644
> index 000000000000..e130f124ed52
> --- /dev/null
> +++ b/Documentation/virt/gunyah/message-queue.rst
> <snipped>...
> +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 1024 bytes in length. It raises a hypercall
> + with the message to inform the hypervisor to add the message to
> + message queue 1's queue.
> +2. Gunyah raises the corresponding interrupt for VM_B 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.
> +
The nested list above should be separated with blank lines to be
rendered properly:
---- >8 ----
diff --git a/Documentation/virt/gunyah/message-queue.rst b/Documentation/virt/gunyah/message-queue.rst
index e130f124ed525a..afaad99db215e6 100644
--- a/Documentation/virt/gunyah/message-queue.rst
+++ b/Documentation/virt/gunyah/message-queue.rst
@@ -20,9 +20,11 @@ queue 2 allows VM_B to send messages to VM_A.
with the message to inform the hypervisor to add the message to
message queue 1's queue.
2. Gunyah raises the corresponding interrupt for VM_B 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.
For VM_B to send a message to VM_A, the process is identical, except that hypercalls
Thanks.
--
An old man doll... just what I always wanted! - Clara
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next prev parent reply other threads:[~2022-09-29 3:43 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-28 19:56 [PATCH v4 00/14] Drivers for gunyah hypervisor Elliot Berman
2022-09-28 19:56 ` [PATCH v4 01/14] docs: gunyah: Introduce Gunyah Hypervisor Elliot Berman
2022-09-29 3:43 ` Bagas Sanjaya [this message]
2022-09-29 4:02 ` Elliot Berman
2022-09-28 19:56 ` [PATCH v4 02/14] dt-bindings: Add binding for gunyah hypervisor Elliot Berman
2022-09-28 19:56 ` [PATCH v4 03/14] gunyah: Common types and error codes for Gunyah hypercalls Elliot Berman
2022-09-28 19:56 ` [PATCH v4 04/14] arm64: smccc: Include alternative-macros.h Elliot Berman
2022-09-28 19:56 ` [PATCH v4 05/14] virt: gunyah: Add hypercalls to identify Gunyah Elliot Berman
2022-09-28 19:56 ` [PATCH v4 06/14] virt: gunyah: Add sysfs nodes Elliot Berman
2022-09-30 12:09 ` Greg Kroah-Hartman
2022-10-04 23:50 ` Elliot Berman
2022-10-05 6:23 ` Greg Kroah-Hartman
2022-09-28 19:56 ` [PATCH v4 07/14] mailbox: Allow direct registration to a channel Elliot Berman
2022-09-28 19:56 ` [PATCH v4 08/14] virt: gunyah: msgq: Add hypercalls to send and receive messages Elliot Berman
2022-09-28 19:56 ` [PATCH v4 09/14] mailbox: Add Gunyah message queue mailbox Elliot Berman
2022-09-29 16:59 ` Bjorn Andersson
2022-09-29 17:37 ` Jassi Brar
2022-09-28 19:56 ` [PATCH v4 10/14] gunyah: sysfs: Add node to describe supported features Elliot Berman
2022-09-29 7:36 ` Joe Perches
2022-09-29 20:47 ` Elliot Berman
2022-10-02 23:30 ` Jeff Johnson
2022-10-02 23:58 ` Joe Perches
2022-09-30 12:06 ` Greg Kroah-Hartman
2022-10-04 23:53 ` Elliot Berman
2022-09-28 19:56 ` [PATCH v4 11/14] gunyah: rsc_mgr: Add resource manager RPC core Elliot Berman
2022-09-28 19:56 ` [PATCH v4 12/14] gunyah: rsc_mgr: Add RPC for console services Elliot Berman
2022-09-30 12:22 ` Greg Kroah-Hartman
2022-10-03 1:46 ` new checkpatch flexible array test ? (was Re: [PATCH v4 12/14] gunyah: rsc_mgr: Add RPC for console services) Joe Perches
2022-10-03 5:29 ` Greg Kroah-Hartman
2022-10-03 5:38 ` Joe Perches
2022-10-31 18:23 ` Gustavo A. R. Silva
2022-09-28 19:56 ` [PATCH v4 13/14] gunyah: rsc_mgr: Add auxiliary devices for console Elliot Berman
2022-09-30 12:19 ` Greg Kroah-Hartman
2022-10-04 23:49 ` Elliot Berman
2022-10-05 6:21 ` Greg Kroah-Hartman
2022-10-05 21:47 ` Elliot Berman
2022-10-06 6:28 ` Greg Kroah-Hartman
2022-09-28 19:56 ` [PATCH v4 14/14] tty: gunyah: Add tty console driver for RM Console Services Elliot Berman
2022-09-30 12:17 ` Greg Kroah-Hartman
2022-10-07 5:59 ` Elliot Berman
2022-10-07 7:40 ` Greg Kroah-Hartman
2022-10-09 20:59 ` Elliot Berman
2022-10-10 20:23 ` Greg Kroah-Hartman
2022-10-10 20:58 ` Elliot Berman
2022-10-11 6:22 ` Greg Kroah-Hartman
2022-10-11 22:04 ` Elliot Berman
2022-10-12 6:53 ` Greg Kroah-Hartman
2022-10-08 7:41 ` Zhou Furong
2022-10-08 9:52 ` Greg Kroah-Hartman
2022-10-03 7:01 ` Jiri Slaby
2022-10-10 18:06 ` Elliot Berman
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