Lines Matching full:cpu
1 Recommendations for KVM CPU model configuration on x86 hosts
5 CPU models on x86 hosts. The goals are to maximise performance, while
6 protecting guest OS against various CPU hardware flaws, and optionally
7 enabling live migration between hosts with heterogeneous CPU models.
10 Two ways to configure CPU models with QEMU / KVM
15 This passes the host CPU model features, model, stepping, exactly to
16 the guest. Note that KVM may filter out some host CPU model features
19 stable CPU is exposed to the guest across hosts. This is the
20 recommended CPU to use, provided live migration is not required.
24 QEMU comes with a number of predefined named CPU models, that
27 isolation from the host CPU, allowing greater flexibility in live
30 In both cases, it is possible to optionally add or remove individual CPU
33 Libvirt supports a third way to configure CPU models known as "Host
35 a CPU model that is similar the host CPU, and then adding extra features
37 guarantee the CPU family, stepping, etc will precisely match the host
38 CPU, as they would with "Host passthrough", but gives much of the
42 ABI compatibility levels for CPU models
50 can be satisfied by the QEMU CPU models. Note that the table only
51 lists the long term stable CPU model versions (eg Haswell-v4).
52 In addition to what is listed, there are also many CPU model
53 aliases which resolve to a different CPU model version,
59 :file: cpu-models-x86-abi.csv
64 Preferred CPU models for Intel x86 hosts
67 The following CPU models are preferred for use on Intel hosts.
68 Administrators / applications are recommended to use the CPU model that
70 mixture of host CPU models between machines, if live migration
71 compatibility is required, use the newest CPU model that is compatible
120 Important CPU features for Intel x86 hosts
123 The following are important CPU features that should be used on Intel
124 x86 hosts, when available in the host CPU. Some of them require explicit
126 all, of the named CPU models listed above. In general all of these
132 Included by default in Haswell, Broadwell & Skylake Intel CPU models.
135 IvyBridge Intel CPU models. Note that some desktop/mobile Westmere
141 Included by default in Intel CPU models with -IBRS suffix.
143 Must be explicitly turned on for Intel CPU models without -IBRS
146 Requires the host CPU microcode to support this feature before it
153 Must be explicitly turned on for all Intel CPU models.
155 Requires the host CPU microcode to support this feature before it can
161 Not included by default in any Intel CPU model.
163 Must be explicitly turned on for all Intel CPU models.
165 Requires the host CPU microcode to support this feature before it
171 Not included by default in any Intel CPU model.
173 Should be explicitly turned on for all Intel CPU models.
175 Note that not all CPU hardware will support this feature.
181 Not included by default in any Intel CPU model.
183 Must be explicitly turned on for all Intel CPU models.
185 Requires the host CPU microcode to support this feature before it
199 affected} in the ``/sys/devices/system/cpu/vulnerabilities/mds`` file.
209 in the ``/sys/devices/system/cpu/vulnerabilities/tsx_async_abort``
222 enabled; *and* (b) the guest has ``rtm`` CPU flag enabled.
233 ``/sys/devices/system/cpu/vulnerabilities/tsx_async_abort`` file in
245 ``/sys/devices/system/cpu/vulnerabilities/spectre_v2`` file.
255 in the ``/sys/devices/system/cpu/vulnerabilities/gather_data_sampling``
266 in the ``/sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling``
269 Preferred CPU models for AMD x86 hosts
272 The following CPU models are preferred for use on AMD hosts.
273 Administrators / applications are recommended to use the CPU model that
275 mixture of host CPU models between machines, if live migration
276 compatibility is required, use the newest CPU model that is compatible
283 AMD Opteron 63xx class CPU (2012)
286 AMD Opteron 62xx class CPU (2011)
298 Important CPU features for AMD x86 hosts
301 The following are important CPU features that should be used on AMD x86
302 hosts, when available in the host CPU. Some of them require explicit
304 all, of the named CPU models listed above. In general all of these
310 Included by default in AMD CPU models with -IBPB suffix.
312 Must be explicitly turned on for AMD CPU models without -IBPB suffix.
314 Requires the host CPU microcode to support this feature before it
321 Must be explicitly turned on for all AMD CPU models.
323 Requires the host CPU microcode to support this feature before it
329 Not included by default in any AMD CPU model.
331 Must be explicitly turned on for all AMD CPU models.
343 Not included by default in any AMD CPU model.
345 Must be explicitly turned on for all AMD CPU models.
355 Not included by default in any AMD CPU model.
357 Future hardware generations of CPU will not be vulnerable to
365 Not included by default in any AMD CPU model.
367 Should be explicitly turned on for all AMD CPU models.
369 Note that not all CPU hardware will support this feature.
372 Default x86 CPU models
375 The default QEMU CPU models are designed such that they can run on all
380 The default CPU models will, however, leave the guest OS vulnerable to
381 various CPU hardware flaws, so their use is strongly discouraged.
382 Applications should follow the earlier guidance to setup a better CPU
387 QEMU Virtual CPU version 2.5+ (32 & 64 bit variants)
390 guests, when no ``-cpu`` argument is given to QEMU, or no ``<cpu>`` is
407 Various very old x86 CPU models, mostly predating the introduction
412 Syntax for configuring CPU models
416 CPU models / features in QEMU and libvirt.
425 |qemu_system| -cpu host
431 |qemu_system| -cpu host,vmx=off,...
433 Named CPU models:
437 |qemu_system| -cpu Westmere
439 Named CPU models with feature customization:
443 |qemu_system| -cpu Westmere,pcid=on,...
450 <cpu mode='host-passthrough'/>
454 <cpu mode='host-passthrough'>
457 </cpu>
461 <cpu mode='host-model'/>
465 <cpu mode='host-model'>
468 </cpu>
472 <cpu mode='custom'>
474 </cpu>
478 <cpu mode='custom'>
482 </cpu>