Adds a design document for hyperlaunch device tree structure. Signed-off-by: Christopher Clark Signed-off by: Daniel P. Smith --- .../designs/launch/hyperlaunch-devicetree.rst | 343 ++++++++++++++++++ 1 file changed, 343 insertions(+) create mode 100644 docs/designs/launch/hyperlaunch-devicetree.rst diff --git a/docs/designs/launch/hyperlaunch-devicetree.rst b/docs/designs/launch/hyperlaunch-devicetree.rst new file mode 100644 index 0000000000..f97d357407 --- /dev/null +++ b/docs/designs/launch/hyperlaunch-devicetree.rst @@ -0,0 +1,343 @@ +------------------------------------- +Xen Hyperlaunch Device Tree Bindings +------------------------------------- + +The Xen hyperlaunch device tree adopts the dom0less device tree structure and +extends it to meet the requirements for the hyperlaunch capability. The primary +difference is the introduction of the ``hypervisor`` node that is under the +``/chosen`` node. The move to a dedicated node was driven by: + +1. Reduces the need to walk over nodes that are not of interest, e.g. only + nodes of interest should be in ``/chosen/hypervisor`` + +2. Allows for the domain construction information to easily be sanitized by + simple removing the ``/chosen/hypervisor`` node. + +Example Configuration +--------------------- + +Below are two example device tree definitions for the hypervisor node. The +first is an example of a multiboot-based configuration for x86 and the second +is a module-based configuration for Arm. + +Multiboot x86 Configuration: +"""""""""""""""""""""""""""" + +:: + + hypervisor { + #address-cells = <1>; + #size-cells = <0>; + compatible = “hypervisor,xen” + + // Configuration container + config { + compatible = "xen,config"; + + module { + compatible = "module,microcode", "multiboot,module"; + mb-index = <1>; + }; + + module { + compatible = "module,xsm-policy", "multiboot,module"; + mb-index = <2>; + }; + }; + + // Boot Domain definition + domain { + compatible = "xen,domain"; + + domid = <0x7FF5>; + + // FUNCTION_NONE (0) + // FUNCTION_BOOT (1 << 0) + // FUNCTION_CRASH (1 << 1) + // FUNCTION_CONSOLE (1 << 2) + // FUNCTION_XENSTORE (1 << 30) + // FUNCTION_LEGACY_DOM0 (1 << 31) + functions = <0x00000001>; + + memory = <0x0 0x20000>; + cpus = <1>; + module { + compatible = "module,kernel", "multiboot,module"; + mb-index = <3>; + }; + + module { + compatible = "module,ramdisk", "multiboot,module"; + mb-index = <4>; + }; + module { + compatible = "module,config", "multiboot,module"; + mb-index = <5>; + }; + + // Classic Dom0 definition + domain { + compatible = "xen,domain"; + + domid = <0>; + + // PERMISSION_NONE (0) + // PERMISSION_CONTROL (1 << 0) + // PERMISSION_HARDWARE (1 << 1) + permissions = <3>; + + // FUNCTION_NONE (0) + // FUNCTION_BOOT (1 << 0) + // FUNCTION_CRASH (1 << 1) + // FUNCTION_CONSOLE (1 << 2) + // FUNCTION_XENSTORE (1 << 30) + // FUNCTION_LEGACY_DOM0 (1 << 31) + functions = <0xC0000006>; + + // MODE_PARAVIRTUALIZED (1 << 0) /* PV | PVH/HVM */ + // MODE_ENABLE_DEVICE_MODEL (1 << 1) /* HVM | PVH */ + // MODE_LONG (1 << 2) /* 64 BIT | 32 BIT */ + mode = <5>; /* 64 BIT, PV */ + + // UUID + domain-uuid = [B3 FB 98 FB 8F 9F 67 A3]; + + cpus = <1>; + memory = <0x0 0x20000>; + security-id = “dom0_t; + + module { + compatible = "module,kernel", "multiboot,module"; + mb-index = <6>; + bootargs = "console=hvc0"; + }; + module { + compatible = "module,ramdisk", "multiboot,module"; + mb-index = <7>; + }; + }; + +The multiboot modules supplied when using the above config would be, in order: + +* (the above config, compiled) +* CPU microcode +* XSM policy +* kernel for boot domain +* ramdisk for boot domain +* boot domain configuration file +* kernel for the classic dom0 domain +* ramdisk for the classic dom0 domain + +Module Arm Configuration: +""""""""""""""""""""""""" + +:: + + hypervisor { + compatible = “hypervisor,xen” + + // Configuration container + config { + compatible = "xen,config"; + + module { + compatible = "module,microcode”; + module-addr = <0x0000ff00 0x80>; + }; + + module { + compatible = "module,xsm-policy"; + module-addr = <0x0000ff00 0x80>; + + }; + }; + + // Boot Domain definition + domain { + compatible = "xen,domain"; + + domid = <0x7FF5>; + + // FUNCTION_NONE (0) + // FUNCTION_BOOT (1 << 0) + // FUNCTION_CRASH (1 << 1) + // FUNCTION_CONSOLE (1 << 2) + // FUNCTION_XENSTORE (1 << 30) + // FUNCTION_LEGACY_DOM0 (1 << 31) + functions = <0x00000001>; + + memory = <0x0 0x20000>; + cpus = <1>; + module { + compatible = "module,kernel"; + module-addr = <0x0000ff00 0x80>; + }; + + module { + compatible = "module,ramdisk"; + module-addr = <0x0000ff00 0x80>; + }; + module { + compatible = "module,config"; + module-addr = <0x0000ff00 0x80>; + }; + + // Classic Dom0 definition + domain@0 { + compatible = "xen,domain"; + + domid = <0>; + + // PERMISSION_NONE (0) + // PERMISSION_CONTROL (1 << 0) + // PERMISSION_HARDWARE (1 << 1) + permissions = <3>; + + // FUNCTION_NONE (0) + // FUNCTION_BOOT (1 << 0) + // FUNCTION_CRASH (1 << 1) + // FUNCTION_CONSOLE (1 << 2) + // FUNCTION_XENSTORE (1 << 30) + // FUNCTION_LEGACY_DOM0 (1 << 31) + functions = <0xC0000006>; + + // MODE_PARAVIRTUALIZED (1 << 0) /* PV | PVH/HVM */ + // MODE_ENABLE_DEVICE_MODEL (1 << 1) /* HVM | PVH */ + // MODE_LONG (1 << 2) /* 64 BIT | 32 BIT */ + mode = <5>; /* 64 BIT, PV */ + + // UUID + domain-uuid = [B3 FB 98 FB 8F 9F 67 A3]; + + cpus = <1>; + memory = <0x0 0x20000>; + security-id = “dom0_t”; + + module { + compatible = "module,kernel"; + module-addr = <0x0000ff00 0x80>; + bootargs = "console=hvc0"; + }; + module { + compatible = "module,ramdisk"; + module-addr = <0x0000ff00 0x80>; + }; + }; + +The modules that would be supplied when using the above config would be: + +* (the above config, compiled into hardware tree) +* CPU microcode +* XSM policy +* kernel for boot domain +* ramdisk for boot domain +* boot domain configuration file +* kernel for the classic dom0 domain +* ramdisk for the classic dom0 domain + +The hypervisor device tree would be compiled into the hardware device tree and +provided to Xen using the standard method currently in use. The remaining +modules would need to be loaded in the respective addresses specified in the +`module-addr` property. + + +The Hypervisor node +------------------- + +The hypervisor node is a top level container for the domains that will be built +by hypervisor on start up. On the ``hypervisor`` node the ``compatible`` +property is used to identify the type of hypervisor node present.. + +compatible + Identifies the type of node. Required. + +The Config node +--------------- + +A config node is for detailing any modules that are of interest to Xen itself. +For example this would be where Xen would be informed of microcode or XSM +policy locations. If the modules are multiboot modules and are able to be +located by index within the module chain, the ``mb-index`` property should be +used to specify the index in the multiboot module chain.. If the module will be +located by physical memory address, then the ``module-addr`` property should be +used to identify the location and size of the module. + +compatible + Identifies the type of node. Required. + +The Domain node +--------------- + +A domain node is for describing the construction of a domain. It may provide a +domid property which will be used as the requested domain id for the domain +with a value of “0” signifying to use the next available domain id, which is +the default behavior if omitted. A domain configuration is not able to request +a domid of “0”. After that a domain node may have any of the following +parameters, + +compatible + Identifies the type of node. Required. + +domid + Identifies the domid requested to assign to the domain. Required. + +permissions + This sets what Discretionary Access Control permissions + a domain is assigned. Optional, default is none. + +functions + This identifies what system functions a domain will fulfill. + Optional, the default is none. + +.. note:: The `functions` bits that have been selected to indicate + ``FUNCTION_XENSTORE`` and ``FUNCTION_LEGACY_DOM0`` are the last two bits + (30, 31) such that should these features ever be fully retired, the flags may + be dropped without leaving a gap in the flag set. + +mode + The mode the domain will be executed under. Required. + +domain-uuid + A globally unique identifier for the domain. Optional, + the default is NULL. + +cpus + The number of vCPUs to be assigned to the domain. Optional, + the default is “1”. + +memory + The amount of memory to assign to the domain, in KBs. + Required. + +security-id + The security identity to be assigned to the domain when XSM + is the access control mechanism being used. Optional, + the default is “domu_t”. + +The Module node +--------------- + +This node describes a boot module loaded by the boot loader. The required +compatible property follows the format: module, where type can be +“kernel”, “ramdisk”, “device-tree”, “microcode”, “xsm-policy” or “config”. In +the case the module is a multiboot module, the additional property string +“multiboot,module” may be present. One of two properties is required and +identifies how to locate the module. They are the mb-index, used for multiboot +modules, and the module-addr for memory address based location. + +compatible + This identifies what the module is and thus what the hypervisor + should use the module for during domain construction. Required. + +mb-index + This identifies the index for this module in the multiboot module chain. + Required for multiboot environments. + +module-addr + This identifies where in memory this module is located. Required for + non-multiboot environments. + +bootargs + This is used to provide the boot params to kernel modules. + +.. note:: The bootargs property is intended for situations where the same kernel multiboot module is used for more than one domain. -- 2.20.1