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| author | Peter Maydell | 2020-02-28 16:36:03 +0100 |
|---|---|---|
| committer | Peter Maydell | 2020-03-06 11:05:12 +0100 |
| commit | 2f4325df9e82507c7d55d1c7e2c72f2fdaf0237a (patch) | |
| tree | 1d8ac8fac5454d69f58fbc8179bd4bb7f1214b81 /docs/system/managed-startup.rst | |
| parent | docs/system: Convert security.texi to rST format (diff) | |
| download | qemu-2f4325df9e82507c7d55d1c7e2c72f2fdaf0237a.tar.gz qemu-2f4325df9e82507c7d55d1c7e2c72f2fdaf0237a.tar.xz qemu-2f4325df9e82507c7d55d1c7e2c72f2fdaf0237a.zip | |
docs/system: convert managed startup to rST.
Fix one typo in the process and format more option and
command names as literal text, but make no significant
changes to the content.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200228153619.9906-18-peter.maydell@linaro.org
Message-id: 20200226113034.6741-17-pbonzini@redhat.com
Diffstat (limited to 'docs/system/managed-startup.rst')
| -rw-r--r-- | docs/system/managed-startup.rst | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/docs/system/managed-startup.rst b/docs/system/managed-startup.rst new file mode 100644 index 0000000000..9bcf98ea79 --- /dev/null +++ b/docs/system/managed-startup.rst @@ -0,0 +1,35 @@ +Managed start up options +======================== + +In system mode emulation, it's possible to create a VM in a paused +state using the ``-S`` command line option. In this state the machine +is completely initialized according to command line options and ready +to execute VM code but VCPU threads are not executing any code. The VM +state in this paused state depends on the way QEMU was started. It +could be in: + +- initial state (after reset/power on state) +- with direct kernel loading, the initial state could be amended to execute + code loaded by QEMU in the VM's RAM and with incoming migration +- with incoming migration, initial state will be amended with the migrated + machine state after migration completes + +This paused state is typically used by users to query machine state and/or +additionally configure the machine (by hotplugging devices) in runtime before +allowing VM code to run. + +However, at the ``-S`` pause point, it's impossible to configure options +that affect initial VM creation (like: ``-smp``/``-m``/``-numa`` ...) or +cold plug devices. The experimental ``--preconfig`` command line option +allows pausing QEMU before the initial VM creation, in a "preconfig" state, +where additional queries and configuration can be performed via QMP +before moving on to the resulting configuration startup. In the +preconfig state, QEMU only allows a limited set of commands over the +QMP monitor, where the commands do not depend on an initialized +machine, including but not limited to: + +- ``qmp_capabilities`` +- ``query-qmp-schema`` +- ``query-commands`` +- ``query-status`` +- ``x-exit-preconfig`` |