[v13,15/24] docs: gunyah: Document Gunyah VM Manager
Commit Message
Document the ioctls and usage of Gunyah VM Manager driver.
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
---
Documentation/virt/gunyah/index.rst | 1 +
Documentation/virt/gunyah/vm-manager.rst | 82 ++++++++++++++++++++++++
2 files changed, 83 insertions(+)
create mode 100644 Documentation/virt/gunyah/vm-manager.rst
Comments
On 5/9/23 3:47 PM, Elliot Berman wrote:
> Document the ioctls and usage of Gunyah VM Manager driver.
>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
This patch does not apply, because at this point in the
series, "Documentation/virt/gunyah/index.rst" does not
exist. I'm going to ignore that.
I have some suggestions, but this generally looks good.
I'll wait to see v14 with the full "index.rst" before I
give my Reviewed-by.
-Alex
> ---
> Documentation/virt/gunyah/index.rst | 1 +
> Documentation/virt/gunyah/vm-manager.rst | 82 ++++++++++++++++++++++++
> 2 files changed, 83 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 74aa345e0a14..7058249825b1 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..50d8ae7fabcd
> --- /dev/null
> +++ b/Documentation/virt/gunyah/vm-manager.rst
> @@ -0,0 +1,82 @@
> +.. 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.
Does everyone know what "non-proxy-scheduled virtual machines" are?
> +Except for some basic information about the location of initial binaries,
> +most of the configuration about a Gunyah virtual machine is described in the
> +VM's devicetree. The devicetree is generated by userspace. Interacting with the
> +virtual machine is still done via the kernel and VM configuration requires some
> +of the corresponding functionality to be set up in the kernel. For instance,
> +sharing userspace memory with a VM is done via the `GH_VM_SET_USER_MEM_REGION`_
> +ioctl. The VM itself is configured to use the memory region via the
> +devicetree.
Without looking at the code, I'm a little unsure what that last
sentence reallly means.
> +
> +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.
Maybe mention it returns a file descriptor representing the created VM?
> +
> +Gunyah VM API Descriptions
> +--------------------------
> +
> +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 regions with the same label is not allowed. Labels are
> +unique per virtual machine.
> +
> +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
Thus, for Linux guests, memory regions must be provided...
> +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`_. It must be page aligned.
> +
> +To add a memory region, call `GH_VM_SET_USER_MEM_REGION`_ with fields set as
> +described above.
> +
> +.. kernel-doc:: include/uapi/linux/gunyah.h
> + :identifiers: gh_userspace_memory_region gh_mem_flags
> +
> +GH_VM_SET_DTB_CONFIG
> +~~~~~~~~~~~~~~~~~~~~
> +
> +This ioctl sets the location of the VM's devicetree blob and is used by Gunyah
> +Resource Manager to allocate resources. The guest physical memory should be part
s/should/must/ /* ? */
> +of the primary memory parcel provided to the VM prior to GH_VM_START.
Is it possible to provide multiple memory parcels? If so, is the
"primary" memory parcel the first?
> +
> +.. kernel-doc:: include/uapi/linux/gunyah.h
> + :identifiers: gh_vm_dtb_config
> +
> +GH_VM_START
> +~~~~~~~~~~~
> +
> +This ioctl starts the VM.
@@ -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
new file mode 100644
@@ -0,0 +1,82 @@
+.. 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.
+
+Except for some basic information about the location of initial binaries,
+most of the configuration about a Gunyah virtual machine is described in the
+VM's devicetree. The devicetree is generated by userspace. Interacting with the
+virtual machine is still done via the kernel and VM configuration requires some
+of the corresponding functionality to be set up in the kernel. For instance,
+sharing userspace memory with a VM is done via the `GH_VM_SET_USER_MEM_REGION`_
+ioctl. The VM itself is configured to use the memory region via the
+devicetree.
+
+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
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+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. Labels are
+unique per virtual machine.
+
+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`_. It must be page aligned.
+
+To add a memory region, call `GH_VM_SET_USER_MEM_REGION`_ with fields set as
+described above.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+ :identifiers: gh_userspace_memory_region gh_mem_flags
+
+GH_VM_SET_DTB_CONFIG
+~~~~~~~~~~~~~~~~~~~~
+
+This ioctl sets the location of the VM's devicetree blob and is used by Gunyah
+Resource Manager to allocate resources. The guest physical memory should be part
+of the primary memory parcel provided to the VM prior to GH_VM_START.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+ :identifiers: gh_vm_dtb_config
+
+GH_VM_START
+~~~~~~~~~~~
+
+This ioctl starts the VM.