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authorRichard Henderson <richard.henderson@linaro.org>2021-12-17 09:55:14 -0800
committerRichard Henderson <richard.henderson@linaro.org>2021-12-17 09:55:14 -0800
commit93dc314c9225e103487ae22b62da1ac59ac86325 (patch)
tree275f2baa8247550f15991852ff3d662c307f252c /docs
parent48c03a0e13f49e8dff9a8ac37fff43e00a0a9bb3 (diff)
parent0e6232bc3cb96bdf6fac1b5d7659aa9887afe657 (diff)
Merge tag 'pull-ppc-20211217' of https://github.com/legoater/qemu into staging
ppc 7.0 queue: * General cleanup for Mac machines (Peter) * Fixes for FPU exceptions (Lucas) * Support for new ISA31 instructions (Matheus) * Fixes for ivshmem (Daniel) * Cleanups for PowerNV PHB (Christophe and Cedric) * Updates of PowerNV and pSeries documentation (Leonardo and Daniel) * Fixes for PowerNV (Daniel) * Large cleanup of FPU implementation (Richard) * Removal of SoftTLBs support for PPC74x CPUs (Fabiano) * Fixes for exception models in MPCx and 60x CPUs (Fabiano) * Removal of 401/403 CPUs (Cedric) * Deprecation of taihu machine (Thomas) * Large rework of PPC405 machine (Cedric) * Fixes for VSX instructions (Victor and Matheus) * Fix for e6500 CPU (Fabiano) * Initial support for PMU (Daniel) # gpg: Signature made Fri 17 Dec 2021 09:20:31 AM PST # gpg: using RSA key A0F66548F04895EBFE6B0B6051A343C7CFFBECA1 # gpg: Good signature from "Cédric Le Goater <clg@kaod.org>" [unknown] # gpg: WARNING: This key is not certified with a trusted signature! # gpg: There is no indication that the signature belongs to the owner. # Primary key fingerprint: A0F6 6548 F048 95EB FE6B 0B60 51A3 43C7 CFFB ECA1 * tag 'pull-ppc-20211217' of https://github.com/legoater/qemu: (101 commits) ppc/pnv: Use QOM hierarchy to scan PEC PHB4 devices ppc/pnv: Move realize of PEC stacks under the PEC model ppc/pnv: Remove "system-memory" property from PHB4 PEC ppc/pnv: Compute the PHB index from the PHB4 PEC model ppc/pnv: Introduce a num_stack class attribute ppc/pnv: Introduce a "chip" property under the PHB4 model ppc/pnv: Introduce version and device_id class atributes for PHB4 devices ppc/pnv: Introduce a num_pecs class attribute for PHB4 PEC devices ppc/pnv: Use QOM hierarchy to scan PHB3 devices ppc/pnv: Move mapping of the PHB3 CQ regions under pnv_pbcq_realize() ppc/pnv: Drop the "num-phbs" property ppc/pnv: Use the chip class to check the index of PHB3 devices ppc/pnv: Introduce a "chip" property under PHB3 PPC64/TCG: Implement 'rfebb' instruction target/ppc/power8-pmu.c: add PM_RUN_INST_CMPL (0xFA) event target/ppc: enable PMU instruction count target/ppc: enable PMU counter overflow with cycle events target/ppc: PMU: update counters on MMCR1 write target/ppc: PMU: update counters on PMCs r/w target/ppc: PMU basic cycle count for pseries TCG ... Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r--docs/about/deprecated.rst9
-rw-r--r--docs/specs/ppc-spapr-hcalls.rst100
-rw-r--r--docs/specs/ppc-spapr-hcalls.txt78
-rw-r--r--docs/system/ppc/powernv.rst68
-rw-r--r--docs/system/ppc/pseries.rst226
5 files changed, 376 insertions, 105 deletions
diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst
index ff7488cb63..5693abb663 100644
--- a/docs/about/deprecated.rst
+++ b/docs/about/deprecated.rst
@@ -315,6 +315,15 @@ This machine is deprecated because we have enough AST2500 based OpenPOWER
machines. It can be easily replaced by the ``witherspoon-bmc`` or the
``romulus-bmc`` machines.
+PPC 405 ``taihu`` machine (since 7.0)
+'''''''''''''''''''''''''''''''''''''
+
+The PPC 405 CPU is a system-on-a-chip, so all 405 machines are very similar,
+except for some external periphery. However, the periphery of the ``taihu``
+machine is hardly emulated at all (e.g. neither the LCD nor the USB part had
+been implemented), so there is not much value added by this board. Use the
+``ref405ep`` machine instead.
+
Backend options
---------------
diff --git a/docs/specs/ppc-spapr-hcalls.rst b/docs/specs/ppc-spapr-hcalls.rst
new file mode 100644
index 0000000000..28daf9734a
--- /dev/null
+++ b/docs/specs/ppc-spapr-hcalls.rst
@@ -0,0 +1,100 @@
+sPAPR hypervisor calls
+----------------------
+
+When used with the ``pseries`` machine type, ``qemu-system-ppc64`` implements
+a set of hypervisor calls (a.k.a. hcalls) defined in the `Linux on Power
+Architecture Reference document (LoPAR)
+<https://cdn.openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200812.pdf>`_.
+This document is a subset of the Power Architecture Platform Reference (PAPR+)
+specification (IBM internal only), which is what PowerVM, the IBM proprietary
+hypervisor, adheres to.
+
+The subset in LoPAR is selected based on the requirements of Linux as a guest.
+
+In addition to those calls, we have added our own private hypervisor
+calls which are mostly used as a private interface between the firmware
+running in the guest and QEMU.
+
+All those hypercalls start at hcall number 0xf000 which correspond
+to an implementation specific range in PAPR.
+
+H_RTAS (0xf000)
+^^^^^^^^^^^^^^^
+
+RTAS stands for Run-Time Abstraction Sercies and is a set of runtime services
+generally provided by the firmware inside the guest to the operating system. It
+predates the existence of hypervisors (it was originally an extension to Open
+Firmware) and is still used by PAPR and LoPAR to provide various services that
+are not performance sensitive.
+
+We currently implement the RTAS services in QEMU itself. The actual RTAS
+"firmware" blob in the guest is a small stub of a few instructions which
+calls our private H_RTAS hypervisor call to pass the RTAS calls to QEMU.
+
+Arguments:
+
+ ``r3``: ``H_RTAS (0xf000)``
+
+ ``r4``: Guest physical address of RTAS parameter block.
+
+Returns:
+
+ ``H_SUCCESS``: Successfully called the RTAS function (RTAS result will have
+ been stored in the parameter block).
+
+ ``H_PARAMETER``: Unknown token.
+
+H_LOGICAL_MEMOP (0xf001)
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+When the guest runs in "real mode" (in powerpc terminology this means with MMU
+disabled, i.e. guest effective address equals to guest physical address), it
+only has access to a subset of memory and no I/Os.
+
+PAPR and LoPAR provides a set of hypervisor calls to perform cacheable or
+non-cacheable accesses to any guest physical addresses that the
+guest can use in order to access IO devices while in real mode.
+
+This is typically used by the firmware running in the guest.
+
+However, doing a hypercall for each access is extremely inefficient
+(even more so when running KVM) when accessing the frame buffer. In
+that case, things like scrolling become unusably slow.
+
+This hypercall allows the guest to request a "memory op" to be applied
+to memory. The supported memory ops at this point are to copy a range
+of memory (supports overlap of source and destination) and XOR which
+is used by our SLOF firmware to invert the screen.
+
+Arguments:
+
+ ``r3 ``: ``H_LOGICAL_MEMOP (0xf001)``
+
+ ``r4``: Guest physical address of destination.
+
+ ``r5``: Guest physical address of source.
+
+ ``r6``: Individual element size, defined by the binary logarithm of the
+ desired size. Supported values are:
+
+ ``0`` = 1 byte
+
+ ``1`` = 2 bytes
+
+ ``2`` = 4 bytes
+
+ ``3`` = 8 bytes
+
+ ``r7``: Number of elements.
+
+ ``r8``: Operation. Supported values are:
+
+ ``0``: copy
+
+ ``1``: xor
+
+Returns:
+
+ ``H_SUCCESS``: Success.
+
+ ``H_PARAMETER``: Invalid argument.
diff --git a/docs/specs/ppc-spapr-hcalls.txt b/docs/specs/ppc-spapr-hcalls.txt
deleted file mode 100644
index 93fe3da91b..0000000000
--- a/docs/specs/ppc-spapr-hcalls.txt
+++ /dev/null
@@ -1,78 +0,0 @@
-When used with the "pseries" machine type, QEMU-system-ppc64 implements
-a set of hypervisor calls using a subset of the server "PAPR" specification
-(IBM internal at this point), which is also what IBM's proprietary hypervisor
-adheres too.
-
-The subset is selected based on the requirements of Linux as a guest.
-
-In addition to those calls, we have added our own private hypervisor
-calls which are mostly used as a private interface between the firmware
-running in the guest and QEMU.
-
-All those hypercalls start at hcall number 0xf000 which correspond
-to an implementation specific range in PAPR.
-
-- H_RTAS (0xf000)
-
-RTAS is a set of runtime services generally provided by the firmware
-inside the guest to the operating system. It predates the existence
-of hypervisors (it was originally an extension to Open Firmware) and
-is still used by PAPR to provide various services that aren't performance
-sensitive.
-
-We currently implement the RTAS services in QEMU itself. The actual RTAS
-"firmware" blob in the guest is a small stub of a few instructions which
-calls our private H_RTAS hypervisor call to pass the RTAS calls to QEMU.
-
-Arguments:
-
- r3 : H_RTAS (0xf000)
- r4 : Guest physical address of RTAS parameter block
-
-Returns:
-
- H_SUCCESS : Successfully called the RTAS function (RTAS result
- will have been stored in the parameter block)
- H_PARAMETER : Unknown token
-
-- H_LOGICAL_MEMOP (0xf001)
-
-When the guest runs in "real mode" (in powerpc lingua this means
-with MMU disabled, ie guest effective == guest physical), it only
-has access to a subset of memory and no IOs.
-
-PAPR provides a set of hypervisor calls to perform cacheable or
-non-cacheable accesses to any guest physical addresses that the
-guest can use in order to access IO devices while in real mode.
-
-This is typically used by the firmware running in the guest.
-
-However, doing a hypercall for each access is extremely inefficient
-(even more so when running KVM) when accessing the frame buffer. In
-that case, things like scrolling become unusably slow.
-
-This hypercall allows the guest to request a "memory op" to be applied
-to memory. The supported memory ops at this point are to copy a range
-of memory (supports overlap of source and destination) and XOR which
-is used by our SLOF firmware to invert the screen.
-
-Arguments:
-
- r3: H_LOGICAL_MEMOP (0xf001)
- r4: Guest physical address of destination
- r5: Guest physical address of source
- r6: Individual element size
- 0 = 1 byte
- 1 = 2 bytes
- 2 = 4 bytes
- 3 = 8 bytes
- r7: Number of elements
- r8: Operation
- 0 = copy
- 1 = xor
-
-Returns:
-
- H_SUCCESS : Success
- H_PARAMETER : Invalid argument
-
diff --git a/docs/system/ppc/powernv.rst b/docs/system/ppc/powernv.rst
index 86186b7d2c..c8f9762342 100644
--- a/docs/system/ppc/powernv.rst
+++ b/docs/system/ppc/powernv.rst
@@ -1,7 +1,7 @@
-PowerNV family boards (``powernv8``, ``powernv9``)
+PowerNV family boards (``powernv8``, ``powernv9``, ``powernv10``)
==================================================================
-PowerNV (as Non-Virtualized) is the "baremetal" platform using the
+PowerNV (as Non-Virtualized) is the "bare metal" platform using the
OPAL firmware. It runs Linux on IBM and OpenPOWER systems and it can
be used as an hypervisor OS, running KVM guests, or simply as a host
OS.
@@ -16,16 +16,14 @@ Supported devices
-----------------
* Multi processor support for POWER8, POWER8NVL and POWER9.
- * XSCOM, serial communication sideband bus to configure chiplets
- * Simple LPC Controller
- * Processor Service Interface (PSI) Controller
- * Interrupt Controller, XICS (POWER8) and XIVE (POWER9)
- * POWER8 PHB3 PCIe Host bridge and POWER9 PHB4 PCIe Host bridge
- * Simple OCC is an on-chip microcontroller used for power management
- tasks
- * iBT device to handle BMC communication, with the internal BMC
- simulator provided by QEMU or an external BMC such as an Aspeed
- QEMU machine.
+ * XSCOM, serial communication sideband bus to configure chiplets.
+ * Simple LPC Controller.
+ * Processor Service Interface (PSI) Controller.
+ * Interrupt Controller, XICS (POWER8) and XIVE (POWER9) and XIVE2 (Power10).
+ * POWER8 PHB3 PCIe Host bridge and POWER9 PHB4 PCIe Host bridge.
+ * Simple OCC is an on-chip micro-controller used for power management tasks.
+ * iBT device to handle BMC communication, with the internal BMC simulator
+ provided by QEMU or an external BMC such as an Aspeed QEMU machine.
* PNOR containing the different firmware partitions.
Missing devices
@@ -33,31 +31,42 @@ Missing devices
A lot is missing, among which :
- * POWER10 processor
- * XIVE2 (POWER10) interrupt controller
- * I2C controllers (yet to be merged)
- * NPU/NPU2/NPU3 controllers
- * EEH support for PCIe Host bridge controllers
- * NX controller
- * VAS controller
- * chipTOD (Time Of Day)
+ * I2C controllers (yet to be merged).
+ * NPU/NPU2/NPU3 controllers.
+ * EEH support for PCIe Host bridge controllers.
+ * NX controller.
+ * VAS controller.
+ * chipTOD (Time Of Day).
* Self Boot Engine (SBE).
- * FSI bus
+ * FSI bus.
Firmware
--------
The OPAL firmware (OpenPower Abstraction Layer) for OpenPower systems
includes the runtime services ``skiboot`` and the bootloader kernel and
-initramfs ``skiroot``. Source code can be found on GitHub:
+initramfs ``skiroot``. Source code can be found on the `OpenPOWER account at
+GitHub <https://github.com/open-power>`_.
- https://github.com/open-power.
-
-Prebuilt images of ``skiboot`` and ``skiroot`` are made available on the `OpenPOWER <https://github.com/open-power/op-build/releases/>`__ site.
+Prebuilt images of ``skiboot`` and ``skiroot`` are made available on the
+`OpenPOWER <https://github.com/open-power/op-build/releases/>`__ site.
QEMU includes a prebuilt image of ``skiboot`` which is updated when a
more recent version is required by the models.
+Current acceleration status
+---------------------------
+
+KVM acceleration in Linux Power hosts is provided by the kvm-hv and
+kvm-pr modules. kvm-hv is adherent to PAPR and it's not compliant with
+powernv. kvm-pr in theory could be used as a valid accel option but
+this isn't supported by kvm-pr at this moment.
+
+To spare users from dealing with not so informative errors when attempting
+to use accel=kvm, the powernv machine will throw an error informing that
+KVM is not supported. This can be revisited in the future if kvm-pr (or
+any other KVM alternative) is usable as KVM accel for this machine.
+
Boot options
------------
@@ -83,6 +92,7 @@ and a SATA disk :
Complex PCIe configuration
~~~~~~~~~~~~~~~~~~~~~~~~~~
+
Six PHBs are defined per chip (POWER9) but no default PCI layout is
provided (to be compatible with libvirt). One PCI device can be added
on any of the available PCIe slots using command line options such as:
@@ -157,7 +167,7 @@ one on the command line :
The files `palmetto-SDR.bin <http://www.kaod.org/qemu/powernv/palmetto-SDR.bin>`__
and `palmetto-FRU.bin <http://www.kaod.org/qemu/powernv/palmetto-FRU.bin>`__
define a Sensor Data Record repository and a Field Replaceable Unit
-inventory for a palmetto BMC. They can be used to extend the QEMU BMC
+inventory for a Palmetto BMC. They can be used to extend the QEMU BMC
simulator.
.. code-block:: bash
@@ -189,4 +199,8 @@ CAVEATS
-------
* No support for multiple HW threads (SMT=1). Same as pseries.
- * CPU can hang when doing intensive I/Os. Use ``-append powersave=off`` in that case.
+
+Maintainer contact information
+------------------------------
+
+Cédric Le Goater <clg@kaod.org>
diff --git a/docs/system/ppc/pseries.rst b/docs/system/ppc/pseries.rst
index 932d4dd17d..72e315eff6 100644
--- a/docs/system/ppc/pseries.rst
+++ b/docs/system/ppc/pseries.rst
@@ -1,12 +1,238 @@
pSeries family boards (``pseries``)
===================================
+The Power machine para-virtualized environment described by the `Linux on Power
+Architecture Reference document (LoPAR)
+<https://openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200812.pdf>`_
+is called pSeries. This environment is also known as sPAPR, System p guests, or
+simply Power Linux guests (although it is capable of running other operating
+systems, such as AIX).
+
+Even though pSeries is designed to behave as a guest environment, it is also
+capable of acting as a hypervisor OS, providing, on that role, nested
+virtualization capabilities.
+
Supported devices
-----------------
+ * Multi processor support for many Power processors generations: POWER7,
+ POWER7+, POWER8, POWER8NVL, POWER9, and Power10. Support for POWER5+ exists,
+ but its state is unknown.
+ * Interrupt Controller, XICS (POWER8) and XIVE (POWER9 and Power10)
+ * vPHB PCIe Host bridge.
+ * vscsi and vnet devices, compatible with the same devices available on a
+ PowerVM hypervisor with VIOS managing LPARs.
+ * Virtio based devices.
+ * PCIe device pass through.
+
Missing devices
---------------
+ * SPICE support.
Firmware
--------
+
+`SLOF <https://github.com/aik/SLOF>`_ (Slimline Open Firmware) is an
+implementation of the `IEEE 1275-1994, Standard for Boot (Initialization
+Configuration) Firmware: Core Requirements and Practices
+<https://standards.ieee.org/standard/1275-1994.html>`_.
+
+QEMU includes a prebuilt image of SLOF which is updated when a more recent
+version is required.
+
+Build directions
+----------------
+
+.. code-block:: bash
+
+ ./configure --target-list=ppc64-softmmu && make
+
+Running instructions
+--------------------
+
+Someone can select the pSeries machine type by running QEMU with the following
+options:
+
+.. code-block:: bash
+
+ qemu-system-ppc64 -M pseries <other QEMU arguments>
+
+sPAPR devices
+-------------
+
+The sPAPR specification defines a set of para-virtualized devices, which are
+also supported by the pSeries machine in QEMU and can be instantiated with the
+``-device`` option:
+
+* ``spapr-vlan`` : a virtual network interface.
+* ``spapr-vscsi`` : a virtual SCSI disk interface.
+* ``spapr-rng`` : a pseudo-device for passing random number generator data to the
+ guest (see the `H_RANDOM hypercall feature
+ <https://wiki.qemu.org/Features/HRandomHypercall>`_ for details).
+* ``spapr-vty``: a virtual teletype.
+* ``spapr-pci-host-bridge``: a PCI host bridge.
+* ``tpm-spapr``: a Trusted Platform Module (TPM).
+* ``spapr-tpm-proxy``: a TPM proxy.
+
+These are compatible with the devices historically available for use when
+running the IBM PowerVM hypervisor with LPARs.
+
+However, since these devices have originally been specified with another
+hypervisor and non-Linux guests in mind, you should use the virtio counterparts
+(virtio-net, virtio-blk/scsi and virtio-rng for instance) if possible instead,
+since they will most probably give you better performance with Linux guests in a
+QEMU environment.
+
+The pSeries machine in QEMU is always instantiated with the following devices:
+
+* A NVRAM device (``spapr-nvram``).
+* A virtual teletype (``spapr-vty``).
+* A PCI host bridge (``spapr-pci-host-bridge``).
+
+Hence, it is not needed to add them manually, unless you use the ``-nodefaults``
+command line option in QEMU.
+
+In the case of the default ``spapr-nvram`` device, if someone wants to make the
+contents of the NVRAM device persistent, they will need to specify a PFLASH
+device when starting QEMU, i.e. either use
+``-drive if=pflash,file=<filename>,format=raw`` to set the default PFLASH
+device, or specify one with an ID
+(``-drive if=none,file=<filename>,format=raw,id=pfid``) and pass that ID to the
+NVRAM device with ``-global spapr-nvram.drive=pfid``.
+
+sPAPR specification
+^^^^^^^^^^^^^^^^^^^
+
+The main source of documentation on the sPAPR standard is the `Linux on Power
+Architecture Reference document (LoPAR)
+<https://openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200812.pdf>`_.
+However, documentation specific to QEMU's implementation of the specification
+can also be found in QEMU documentation:
+
+.. toctree::
+ :maxdepth: 1
+
+ ../../specs/ppc-spapr-hcalls.rst
+ ../../specs/ppc-spapr-numa.rst
+ ../../specs/ppc-spapr-xive.rst
+
+Other documentation available in QEMU docs directory:
+
+* Hot plug (``/docs/specs/ppc-spapr-hotplug.txt``).
+* Hypervisor calls needed by the Ultravisor
+ (``/docs/specs/ppc-spapr-uv-hcalls.txt``).
+
+Switching between the KVM-PR and KVM-HV kernel module
+-----------------------------------------------------
+
+Currently, there are two implementations of KVM on Power, ``kvm_hv.ko`` and
+``kvm_pr.ko``.
+
+
+If a host supports both KVM modes, and both KVM kernel modules are loaded, it is
+possible to switch between the two modes with the ``kvm-type`` parameter:
+
+* Use ``qemu-system-ppc64 -M pseries,accel=kvm,kvm-type=PR`` to use the
+ ``kvm_pr.ko`` kernel module.
+* Use ``qemu-system-ppc64 -M pseries,accel=kvm,kvm-type=HV`` to use ``kvm_hv.ko``
+ instead.
+
+KVM-PR
+^^^^^^
+
+KVM-PR uses the so-called **PR**\ oblem state of the PPC CPUs to run the guests,
+i.e. the virtual machine is run in user mode and all privileged instructions
+trap and have to be emulated by the host. That means you can run KVM-PR inside
+a pSeries guest (or a PowerVM LPAR for that matter), and that is where it has
+originated, as historically (prior to POWER7) it was not possible to run Linux
+on hypervisor mode on a Power processor (this function was restricted to
+PowerVM, the IBM proprietary hypervisor).
+
+Because all privileged instructions are trapped, guests that use a lot of
+privileged instructions run quite slow with KVM-PR. On the other hand, because
+of that, this kernel module can run on pretty much every PPC hardware, and is
+able to emulate a lot of guests CPUs. This module can even be used to run other
+PowerPC guests like an emulated PowerMac.
+
+As KVM-PR can be run inside a pSeries guest, it can also provide nested
+virtualization capabilities (i.e. running a guest from within a guest).
+
+It is important to notice that, as KVM-HV provides a much better execution
+performance, maintenance work has been much more focused on it in the past
+years. Maintenance for KVM-PR has been minimal.
+
+In order to run KVM-PR guests with POWER9 processors, someone will need to start
+QEMU with ``kernel_irqchip=off`` command line option.
+
+KVM-HV
+^^^^^^
+
+KVM-HV uses the hypervisor mode of more recent Power processors, that allow
+access to the bare metal hardware directly. Although POWER7 had this capability,
+it was only starting with POWER8 that this was officially supported by IBM.
+
+Originally, KVM-HV was only available when running on a PowerNV platform (a.k.a.
+Power bare metal). Although it runs on a PowerNV platform, it can only be used
+to start pSeries guests. As the pSeries guest doesn't have access to the
+hypervisor mode of the Power CPU, it wasn't possible to run KVM-HV on a guest.
+This limitation has been lifted, and now it is possible to run KVM-HV inside
+pSeries guests as well, making nested virtualization possible with KVM-HV.
+
+As KVM-HV has access to privileged instructions, guests that use a lot of these
+can run much faster than with KVM-PR. On the other hand, the guest CPU has to be
+of the same type as the host CPU this way, e.g. it is not possible to specify an
+embedded PPC CPU for the guest with KVM-HV. However, there is at least the
+possibility to run the guest in a backward-compatibility mode of the previous
+CPUs generations, e.g. you can run a POWER7 guest on a POWER8 host by using
+``-cpu POWER8,compat=power7`` as parameter to QEMU.
+
+Modules support
+---------------
+
+As noticed in the sections above, each module can run in a different
+environment. The following table shows with which environment each module can
+run. As long as you are in a supported environment, you can run KVM-PR or KVM-HV
+nested. Combinations not shown in the table are not available.
+
++--------------+------------+------+-------------------+----------+--------+
+| Platform | Host type | Bits | Page table format | KVM-HV | KVM-PR |
++==============+============+======+===================+==========+========+
+| PowerNV | bare metal | 32 | hash | no | yes |
+| | | +-------------------+----------+--------+
+| | | | radix | N/A | N/A |
+| | +------+-------------------+----------+--------+
+| | | 64 | hash | yes | yes |
+| | | +-------------------+----------+--------+
+| | | | radix | yes | no |
++--------------+------------+------+-------------------+----------+--------+
+| pSeries [1]_ | PowerNV | 32 | hash | no | yes |
+| | | +-------------------+----------+--------+
+| | | | radix | N/A | N/A |
+| | +------+-------------------+----------+--------+
+| | | 64 | hash | no | yes |
+| | | +-------------------+----------+--------+
+| | | | radix | yes [2]_ | no |
+| +------------+------+-------------------+----------+--------+
+| | PowerVM | 32 | hash | no | yes |
+| | | +-------------------+----------+--------+
+| | | | radix | N/A | N/A |
+| | +------+-------------------+----------+--------+
+| | | 64 | hash | no | yes |
+| | | +-------------------+----------+--------+
+| | | | radix [3]_ | no | yes |
++--------------+------------+------+-------------------+----------+--------+
+
+.. [1] On POWER9 DD2.1 processors, the page table format on the host and guest
+ must be the same.
+
+.. [2] KVM-HV cannot run nested on POWER8 machines.
+
+.. [3] Introduced on Power10 machines.
+
+Maintainer contact information
+------------------------------
+
+Cédric Le Goater <clg@kaod.org>
+
+Daniel Henrique Barboza <danielhb413@gmail.com>