Re: [PATCH v3 17/33] docs/system: convert managed startup to rST.

["Alex Bennée" <alex.bennee@linaro.org>]

Peter Maydell <peter.maydell@linaro.org> writes:

> 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>
> Message-id: 20200226113034.6741-17-pbonzini@redhat.com

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  docs/system/index.rst           |  2 +-
>  docs/system/managed-startup.rst | 35 +++++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+), 1 deletion(-)
>  create mode 100644 docs/system/managed-startup.rst
>
> diff --git a/docs/system/index.rst b/docs/system/index.rst
> index 5034f903407..d655344fffd 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 00000000000..9bcf98ea790
> --- /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``


-- 
Alex Bennée