system/ppc/pseries.rst

5 The Power machine para-virtualized environment described by the Linux on Power
18    - POWER7, POWER7+
19    - POWER8, POWER8NVL
20    - POWER9
21    - Power10
22    - Power11
23    - Support for POWER5+ also exists, works with correct kernel/userspace
25     - XICS (POWER8)
26     - XIVE (Supported by below:)
27         - POWER9
28         - Power10
29         - Power11
47 implementation of the `IEEE 1275-1994, Standard for Boot (Initialization
49 <https://standards.ieee.org/standard/1275-1994.html>`_.
58 ``-machine pseries,x-vof=on``. When enabled, the firmware acts as a slim
62 relies on ``-kernel`` used with Linux kernels recent enough (v5.4+)
65 Booting via ``-kernel`` supports the following:
67 +-------------------+-------------------+------------------+
68 | kernel            | pseries,x-vof=off | pseries,x-vof=on |
71 +-------------------+-------------------+------------------+
73 +-------------------+-------------------+------------------+
75 +-------------------+-------------------+------------------+
77 +-------------------+-------------------+------------------+
79 ¹ must set kernel-addr=0
84 .. code-block:: bash
86   ./configure --target-list=ppc64-softmmu && make
94 .. code-block:: bash
96   qemu-system-ppc64 -M pseries <other QEMU arguments>
101 The sPAPR specification defines a set of para-virtualized devices, which are
103 ``-device`` option:
105 * ``spapr-vlan`` : a virtual network interface.
106 * ``spapr-vscsi`` : a virtual SCSI disk interface.
107 * ``spapr-rng`` : a pseudo-device for passing random number generator data to the
110 * ``spapr-vty``: a virtual teletype.
111 * ``spapr-pci-host-bridge``: a PCI host bridge.
112 * ``tpm-spapr``: a Trusted Platform Module (TPM).
113 * ``spapr-tpm-proxy``: a TPM proxy.
119 hypervisor and non-Linux guests in mind, you should use the virtio counterparts
120 (virtio-net, virtio-blk/scsi and virtio-rng for instance) if possible instead,
126 * A NVRAM device (``spapr-nvram``).
127 * A virtual teletype (``spapr-vty``).
128 * A PCI host bridge (``spapr-pci-host-bridge``).
130 Hence, it is not needed to add them manually, unless you use the ``-nodefaults``
133 In the case of the default ``spapr-nvram`` device, if someone wants to make the
136 ``-drive if=pflash,file=<filename>,format=raw`` to set the default PFLASH
138 (``-drive if=none,file=<filename>,format=raw,id=pfid``) and pass that ID to the
139 NVRAM device with ``-global spapr-nvram.drive=pfid``.
142 -------------------
151    ../../specs/ppc-spapr-hotplug.rst
152    ../../specs/ppc-spapr-hcalls.rst
153    ../../specs/ppc-spapr-numa.rst
154    ../../specs/ppc-spapr-uv-hcalls.rst
155    ../../specs/ppc-spapr-xive.rst
157 Switching between the KVM-PR and KVM-HV kernel module
160 Currently, there are two implementations of KVM on Power, ``kvm_hv.ko`` and
164 If a host supports both KVM modes, and both KVM kernel modules are loaded, it is
165 possible to switch between the two modes with the ``kvm-type`` parameter:
167 * Use ``qemu-system-ppc64 -M pseries,accel=kvm,kvm-type=PR`` to use the
169 * Use ``qemu-system-ppc64 -M pseries,accel=kvm,kvm-type=HV`` to use ``kvm_hv.ko``
172 KVM-PR
173 ------
175 KVM-PR uses the so-called **PR**\ oblem state of the PPC CPUs to run the guests,
177 trap and have to be emulated by the host. That means you can run KVM-PR inside
184 privileged instructions run quite slow with KVM-PR. On the other hand, because
189 As KVM-PR can be run inside a pSeries guest, it can also provide nested
192 It is important to notice that, as KVM-HV provides a much better execution
194 years. Maintenance for KVM-PR has been minimal.
196 In order to run KVM-PR guests with POWER9 processors, someone will need to start
199 KVM-HV
200 ------
202 KVM-HV uses the hypervisor mode of more recent Power processors, that allow
206 Originally, KVM-HV was only available when running on a PowerNV platform (a.k.a.
209 hypervisor mode of the Power CPU, it wasn't possible to run KVM-HV on a guest.
210 This limitation has been lifted, and now it is possible to run KVM-HV inside
211 pSeries guests as well, making nested virtualization possible with KVM-HV.
213 As KVM-HV has access to privileged instructions, guests that use a lot of these
214 can run much faster than with KVM-PR. On the other hand, the guest CPU has to be
216 embedded PPC CPU for the guest with KVM-HV. However, there is at least the
217 possibility to run the guest in a backward-compatibility mode of the previous
219 ``-cpu POWER8,compat=power7`` as parameter to QEMU.
226 run. As long as you are in a supported environment, you can run KVM-PR or KVM-HV
229 +--------------+------------+------+-------------------+----------+--------+
230 | Platform     | Host type  | Bits | Page table format | KVM-HV   | KVM-PR |
233 |              |            |      +-------------------+----------+--------+
235 |              |            +------+-------------------+----------+--------+
237 |              |            |      +-------------------+----------+--------+
239 +--------------+------------+------+-------------------+----------+--------+
241 |              |            |      +-------------------+----------+--------+
243 |              |            +------+-------------------+----------+--------+
245 |              |            |      +-------------------+----------+--------+
247 |              +------------+------+-------------------+----------+--------+
249 |              |            |      +-------------------+----------+--------+
251 |              |            +------+-------------------+----------+--------+
253 |              |            |      +-------------------+----------+--------+
255 +--------------+------------+------+-------------------+----------+--------+
260 .. [2] KVM-HV cannot run nested on POWER8 machines.
265 .. _power-papr-protected-execution-facility-pef:
268 -----------------------------------------------
286   $ qemu-system-ppc64 \
287       -object pef-guest,id=pef0 \
288       -machine confidential-guest-support=pef0 \
307    2.9 <https://openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200812.pdf>`_.