From 8bfce83a3b50d45b7107a50a6cd61d5304a925a2 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Tue, 25 Jul 2017 15:10:41 +0100 Subject: [PATCH] qemu-options: document existance of versioned machine types The -machine docs did not explain what the versioned machine types are for, nor that they'll be maintained across releases. Signed-off-by: Daniel P. Berrange Message-Id: <20170725141041.1195-1-berrange@redhat.com> Signed-off-by: Paolo Bonzini --- qemu-options.hx | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/qemu-options.hx b/qemu-options.hx index 746b5fa75d..9f6e2adfff 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -49,7 +49,20 @@ STEXI @item -machine [type=]@var{name}[,prop=@var{value}[,...]] @findex -machine Select the emulated machine by @var{name}. Use @code{-machine help} to list -available machines. Supported machine properties are: +available machines. + +For architectures which aim to support live migration compatibility +across releases, each release will introduce a new versioned machine +type. For example, the 2.8.0 release introduced machine types +``pc-i440fx-2.8'' and ``pc-q35-2.8'' for the x86_64/i686 architectures. + +To allow live migration of guests from QEMU version 2.8.0, to QEMU +version 2.9.0, the 2.9.0 version must support the ``pc-i440fx-2.8'' +and ``pc-q35-2.8'' machines too. To allow users live migrating VMs +to skip multiple intermediate releases when upgrading, new releases +of QEMU will support machine types from many previous versions. + +Supported machine properties are: @table @option @item accel=@var{accels1}[:@var{accels2}[:...]] This is used to enable an accelerator. Depending on the target architecture,