From: Peter Maydell Date: Fri, 28 Feb 2020 15:36:03 +0000 (+0000) Subject: docs/system: convert managed startup to rST. X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2f4325df9e82507c7d55d1c7e2c72f2fdaf0237a;p=qemu.git 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 Signed-off-by: Paolo Bonzini Reviewed-by: Alex Bennée Tested-by: Alex Bennée Message-id: 20200228153619.9906-18-peter.maydell@linaro.org Message-id: 20200226113034.6741-17-pbonzini@redhat.com --- diff --git a/docs/system/index.rst b/docs/system/index.rst index 5034f90340..d655344fff 100644 --- a/docs/system/index.rst +++ b/docs/system/index.rst @@ -13,6 +13,6 @@ Contents: .. toctree:: :maxdepth: 2 - + managed-startup security vfio-ap 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``