mirrors/qemu
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

docs/system/arm/virt.rst: Add note on CPU features off by default

Browse Source 
Add a note on CPU features that are off by default in `virt` machines.
Some CPU features will remain off even if a CPU-capable CPU (e.g.,
`-cpu max`) is selected because they require support in both the CPU
itself and in the wider system. Therefore, the user, besides selecting a
CPU that supports such features, must also turn on the feature using a
machine option.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Message-id: 20240122211215.95073-1-gustavo.romero@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Gustavo Romero 2024-01-22 21:12:15 +00:00 committed by Peter Maydell
parent b0d1021ed9
commit 1acf215998
1 changed files with 13 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
docs/system/arm/virt.rst
View File

@ -69,6 +69,19 @@ Supported guest CPU types:
Note that the default is ``cortex-a15``, so for an AArch64 guest you must Note that the default is ``cortex-a15``, so for an AArch64 guest you must
specify a CPU type. specify a CPU type.
Also, please note that passing ``max`` CPU (i.e. ``-cpu max``) won't
enable all the CPU features for a given ``virt`` machine. Where a CPU
architectural feature requires support in both the CPU itself and in the
wider system (e.g. the MTE feature), it may not be enabled by default,
but instead requires a machine option to enable it.
For example, MTE support must be enabled with ``-machine virt,mte=on``,
as well as by selecting an MTE-capable CPU (e.g., ``max``) with the
``-cpu`` option.
See the machine-specific options below, or check them for a given machine
by passing the ``help`` suboption, like: ``-machine virt-9.0,help``.
Graphics output is available, but unlike the x86 PC machine types Graphics output is available, but unlike the x86 PC machine types
there is no default display device enabled: you should select one from there is no default display device enabled: you should select one from
the Display devices section of "-device help". The recommended option the Display devices section of "-device help". The recommended option