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Message-ID: <20221121140009.2353512-21-quic_eberman@quicinc.com>
Date: Mon, 21 Nov 2022 06:00:09 -0800
From: Elliot Berman <quic_eberman@...cinc.com>
To: Bjorn Andersson <quic_bjorande@...cinc.com>,
Jonathan Corbet <corbet@....net>,
Bagas Sanjaya <bagasdotme@...il.com>,
Elliot Berman <quic_eberman@...cinc.com>,
Murali Nalajala <quic_mnalajal@...cinc.com>
CC: Trilok Soni <quic_tsoni@...cinc.com>,
Srivatsa Vaddagiri <quic_svaddagi@...cinc.com>,
Carl van Schaik <quic_cvanscha@...cinc.com>,
Prakruthi Deepak Heragu <quic_pheragu@...cinc.com>,
Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Jassi Brar <jassisinghbrar@...il.com>,
Sudeep Holla <sudeep.holla@....com>,
Mark Rutland <mark.rutland@....com>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
<linux-arm-msm@...r.kernel.org>, <devicetree@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-acpi@...r.kernel.org>
Subject: [PATCH v7 20/20] docs: gunyah: Document Gunyah VM Manager
Document the ioctls and usage of Gunyah VM Manager driver.
Signed-off-by: Elliot Berman <quic_eberman@...cinc.com>
---
Documentation/virt/gunyah/index.rst | 1 +
Documentation/virt/gunyah/vm-manager.rst | 91 ++++++++++++++++++++++++
2 files changed, 92 insertions(+)
create mode 100644 Documentation/virt/gunyah/vm-manager.rst
diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst
index fbadbdd24da7..9019a03b6f3e 100644
--- a/Documentation/virt/gunyah/index.rst
+++ b/Documentation/virt/gunyah/index.rst
@@ -7,6 +7,7 @@ Gunyah Hypervisor
.. toctree::
:maxdepth: 1
+ vm-manager
message-queue
Gunyah is a Type-1 hypervisor which is independent of any OS kernel, and runs in
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
new file mode 100644
index 000000000000..16fb2b98c371
--- /dev/null
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -0,0 +1,91 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+Virtual Machine Manager
+=======================
+
+The Gunyah Virtual Machine Manager is a Linux driver to support launching
+virtual machines using Gunyah. It presently supports launching non-proxy
+scheduled Linux-like virtual machines.
+
+Sample Userspace VMM
+====================
+
+A sample userspace VMM is included in samples/gunyah/ along with a minimal
+devicetree that can be used to launch a VM. To build this sample, enable
+CONFIG_SAMPLE_GUNYAH.
+
+IOCTLs and userspace VMM flows
+==============================
+
+The kernel exposes a char device interface at /dev/gunyah.
+
+To create a VM, use the GH_CREATE_VM ioctl. A successful call will return a
+"Gunyah VM" file descriptor.
+
+/dev/gunyah API Descriptions
+----------------------------
+
+GH_CREATE_VM
+~~~~~~~~~~~~
+
+Creates a Gunyah VM. The argument is reserved for future use and must be 0.
+
+Gunyah VM API Descriptions
+--------------------------
+
+GH_VM_SET_USER_MEM_REGION
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ struct gh_userspace_memory_region {
+ __u32 label;
+ __u32 flags;
+ __u64 guest_phys_addr;
+ __u64 memory_size;
+ __u64 userspace_addr;
+ };
+
+This ioctl allows the user to create or delete a memory parcel for a guest
+virtual machine. Each memory region is uniquely identified by a label;
+attempting to create two regions with the same label is not allowed.
+
+While VMM is guest-agnostic and allows runtime addition of memory regions,
+Linux guest virtual machines do not support accepting memory regions at runtime.
+Thus, memory regions should be provided before starting the VM and the VM must
+be configured to accept these at boot-up.
+
+The guest physical address is used by Linux kernel to check that the requested
+user regions do not overlap and to help find the corresponding memory region
+for calls like GH_VM_SET_DTB_CONFIG.
+
+To delete a memory region, call GH_VM_SET_USER_MEM_REGION with label set to the
+desired region and memory_size set to 0.
+
+The flags field of gh_userspace_memory_region accepts the following bits. All
+other bits must be 0 and are reserved for future use. The ioctl will return
+-EINVAL if an unsupported bit is detected.
+
+ - GH_MEM_ALLOW_READ/GH_MEM_ALLOW_WRITE/GH_MEM_ALLOW_EXEC sets read/write/exec
+ permissions for the guest, respectively.
+ - GH_MEM_LENT means that the memory will be unmapped from the host and be
+ unaccessible by the host while the guest has the region.
+
+GH_VM_SET_DTB_CONFIG
+~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ struct gh_vm_dtb_config {
+ __u64 gpa;
+ __u64 size;
+ };
+
+This ioctl sets the location of the VM's devicetree blob and is used by Gunyah
+Resource Manager to allocate resources.
+
+GH_VM_START
+~~~~~~~~~~~
+
+This ioctl starts the VM.
--
2.25.1
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