From 2147106172266c3f38b167ead97bd17eeaab85a0 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Fri, 28 Feb 2020 15:35:56 +0000 Subject: qemu-doc: move qemu-tech.texi into main section The only remaining content in qemu-tech.texi is a few paragraphs about managed start up options. Move them in the main section about full system emulation. Signed-off-by: Paolo Bonzini Reviewed-by: Peter Maydell Reviewed-by: Alex Bennée Tested-by: Alex Bennée Signed-off-by: Peter Maydell Message-id: 20200228153619.9906-11-peter.maydell@linaro.org Message-id: 20200226113034.6741-11-pbonzini@redhat.com Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- docs/system/managed-startup.texi | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 docs/system/managed-startup.texi (limited to 'docs/system') diff --git a/docs/system/managed-startup.texi b/docs/system/managed-startup.texi new file mode 100644 index 0000000000..ec168095cc --- /dev/null +++ b/docs/system/managed-startup.texi @@ -0,0 +1,35 @@ +@node managed_startup +@section 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: +@table @asis +@item initial state (after reset/power on state) +@item 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 +@item with incoming migration, initial state will by amended with the migrated +machine state after migration completes. +@end table + +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: +@table @asis +@item qmp_capabilities +@item query-qmp-schema +@item query-commands +@item query-status +@item x-exit-preconfig +@end table -- cgit v1.2.3-55-g7522