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[180.214.233.79]) by smtp.gmail.com with ESMTPSA id e1-20020a621e01000000b00537a8d2c2easm3557097pfe.80.2022.09.28.20.43.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Sep 2022 20:43:40 -0700 (PDT) Received: by debian.me (Postfix, from userid 1000) id 27FB410925C; Thu, 29 Sep 2022 10:43:37 +0700 (WIB) Date: Thu, 29 Sep 2022 10:43:36 +0700 From: Bagas Sanjaya To: Elliot Berman Cc: Bjorn Andersson , Jonathan Corbet , Murali Nalajala , Trilok Soni , Srivatsa Vaddagiri , Carl van Schaik , Andy Gross , Dmitry Baryshkov , Jassi Brar , linux-arm-kernel@lists.infradead.org, Mark Rutland , Lorenzo Pieralisi , Sudeep Holla , Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Will Deacon , Catalin Marinas , Arnd Bergmann , Greg Kroah-Hartman , 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 Message-ID: References: <20220928195633.2348848-1-quic_eberman@quicinc.com> <20220928195633.2348848-2-quic_eberman@quicinc.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Q0eTYf0QdFrQIfAA" Content-Disposition: inline In-Reply-To: <20220928195633.2348848-2-quic_eberman@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Q0eTYf0QdFrQIfAA Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Sep 28, 2022 at 12:56:20PM -0700, Elliot Berman wrote: > diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gun= yah/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 > + > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > +Gunyah Hypervisor > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > + > +.. 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 ph= ysical > + 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 ar= e handled > + in the hypervisor and routed to the assigned VM. > + > +- Inter-VM Communication: > + > + There are several different mechanisms provided for communicating betw= een 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 communicati= on. > + > +Architectures supported > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > +AArch64 with a GIC > + > +Resources and Capabilities > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D > + > +Some services or resources provided by the Gunyah hypervisor are describ= ed to a virtual machine by > +capability IDs. For instance, inter-VM communication is performed with d= oorbells 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 ma= nager 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 ca= n 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 "cap= ability IDs" and not a > +"resource IDs". A VM can have multiple capability IDs mapping to the sam= e resource. If 2 VMs have > +access to the same resource, they may not be using the same capability I= D to access that resource > +since the tables are independent per VM. > + > +Resource Manager > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > + > +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 maintai= n a separation of policy > +and mechanism in the platform. On arm64, RM runs at NS-EL1 similar to ot= her 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 | > + +-.-.-.-+ +---.----+ +---.----+ > + | | | | > + +-.-.-----------.------------.----+ > + | | \=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D/ | | > + | \=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D/ | > + | Gunyah | > + +---------------------------------+ > + > +The source for the resource manager is available at https://github.com/q= uic/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 capa= bilities of > +this VM. See Documentation/devicetree/bindings/firmware/gunyah-hyperviso= r.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 > ... > +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 hyper= call > + 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/vi= rt/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 ha= ppens: + a. gh_msgq_send has PUSH flag. Queue is immediately flushed. This is th= e 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. =20 For VM_B to send a message to VM_A, the process is identical, except that = hypercalls Thanks. --=20 An old man doll... just what I always wanted! - Clara --Q0eTYf0QdFrQIfAA Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSSYQ6Cy7oyFNCHrUH2uYlJVVFOowUCYzUUZAAKCRD2uYlJVVFO o1q4APwP+/ERjbxXRPWCORGC4UT/SNYUj+eaww/Whwnueht3ogD/UzH9N4wlowyV bpGIEj6dozRHKf0F907Ypqs4bZQmLw4= =xA7F -----END PGP SIGNATURE----- --Q0eTYf0QdFrQIfAA--