On Wed, Oct 26, 2022 at 11:58:46AM -0700, Elliot Berman wrote:
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
new file mode 100644
index 000000000000..c232ba05de7e
--- /dev/null
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -0,0 +1,94 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+Virtual Machine Manager
+=======================
+
+The Gunyah Virtual Machine Manager is a Linux driver to support launching virtual machines.
+
+Summary
+=======
+
+Gunyah VMM 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 sample minimal devicetree
+that can be used to launch a Linux-like virtual machine under Gunyah. 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 memory 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
+configured to accept those memory regions at boot-up.
+
+The guest physical address is used by Linux to check the requested user regions
+do not overlap and to help find a 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
+memory region of interest and memory_size set to 0.
+
+The flags field of gh_userspace_memory_region can set 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 virtual machine.
I think the wording can be better:
---- >8 ----
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index c232ba05de7e96..772fd970b91d7e 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -4,18 +4,15 @@
Virtual Machine Manager
=======================
-The Gunyah Virtual Machine Manager is a Linux driver to support launching virtual machines.
-
-Summary
-=======
-
-Gunyah VMM presently supports launching non-proxy scheduled Linux-like virtual machines.
+The Gunyah Virtual Machine Manager is a Linux driver for 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 sample minimal devicetree
-that can be used to launch a Linux-like virtual machine under Gunyah. To build this sample, enable
+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
@@ -23,7 +20,8 @@ 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.
+To create a VM, use the GH_CREATE_VM ioctl. A successful call will return a
+"Gunyah VM" file descriptor.
/dev/gunyah API Descriptions
----------------------------
@@ -51,29 +49,28 @@ GH_VM_SET_USER_MEM_REGION
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 memory regions with the same label is not allowed.
+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
-configured to accept those memory regions at boot-up.
+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 to check the requested user regions
-do not overlap and to help find a corresponding memory region for calls like
-GH_VM_SET_DTB_CONFIG.
+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
-memory region of interest and memory_size set to 0.
+desired region and memory_size set to 0.
-The flags field of gh_userspace_memory_region can set the following bits. All
+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_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.
