Document the ioctls and usage of Gunyah VM Manager driver. Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx> --- Documentation/virt/gunyah/index.rst | 1 + Documentation/virt/gunyah/vm-manager.rst | 94 ++++++++++++++++++++++++ 2 files changed, 95 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..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. -- 2.25.1