| Message ID | 20230613172054.3959700-17-quic_eberman@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | Drivers for Gunyah hypervisor | expand |
On 6/13/23 12:20 PM, Elliot Berman wrote: > Document the ioctls and usage of Gunyah VM Manager driver. > > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> A few minor comments below, but regardless: Reviewed-by: Alex Elder <elder@linaro.org> > --- > Documentation/virt/gunyah/index.rst | 1 + > Documentation/virt/gunyah/vm-manager.rst | 83 ++++++++++++++++++++++++ > 2 files changed, 84 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 74aa345e0a144..7058249825b16 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 0000000000000..df0e1a8279bf5 > --- /dev/null > +++ b/Documentation/virt/gunyah/vm-manager.rst > @@ -0,0 +1,83 @@ > +.. 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 virtual machines > +scheduled by Gunyah's scheduler. You referred to this as "behind-the-back" scheduling in patch 1. (I don't know if this terminology is important to use.) > + > +Configuration of a Gunyah virtual machine is done via a devicetree. When the VM > +is launched, memory is provided by the host VM which contains the devictree. > +Gunyah reads the devicetree to configure the memory map and create resources > +such as vCPUs for the VM. Memory can be shared with the VM with > +`GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux > +by adding "functions" to the VM. > + > +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. Maybe reword this a bit so it's clearer that the IOCTL calls are performed on the file descriptor resulting from opening /dev/gunyah? > + > +/dev/gunyah API Descriptions > +---------------------------- > + > +GH_CREATE_VM > +~~~~~~~~~~~~ > + > +Creates a Gunyah VM. The argument is reserved for future use and must be 0. > +A successful call will return a Gunyah VM file descriptor. See > +`Gunyah VM API Descriptions`_ for list of IOCTLs that can be made on this file Maybe "the next section" rather than an explicit reference. But it's fine as-is. Also (because you duplicate "file"): s/on this file/on this/ > +file descriptor. > + > +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 How are memory parcels deleted? (Maybe add a sentence at the end of this section.) > +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, for Linux guests, memory regions should be provided before starting the VM > +and the VM must be configured via the devicetree 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 must 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.
diff --git a/Documentation/virt/gunyah/index.rst b/Documentation/virt/gunyah/index.rst index 74aa345e0a144..7058249825b16 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 0000000000000..df0e1a8279bf5 --- /dev/null +++ b/Documentation/virt/gunyah/vm-manager.rst @@ -0,0 +1,83 @@ +.. 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 virtual machines +scheduled by Gunyah's scheduler. + +Configuration of a Gunyah virtual machine is done via a devicetree. When the VM +is launched, memory is provided by the host VM which contains the devictree. +Gunyah reads the devicetree to configure the memory map and create resources +such as vCPUs for the VM. Memory can be shared with the VM with +`GH_VM_SET_USER_MEM_REGION`_. Userspace can interact with the resources in Linux +by adding "functions" to the VM. + +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. +A successful call will return a Gunyah VM file descriptor. See +`Gunyah VM API Descriptions`_ for list of IOCTLs that can be made on this file +file descriptor. + +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, for Linux guests, memory regions should be provided before starting the VM +and the VM must be configured via the devicetree 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 must 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.
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 | 83 ++++++++++++++++++++++++ 2 files changed, 84 insertions(+) create mode 100644 Documentation/virt/gunyah/vm-manager.rst