[libvirt] [PATCH v4] Add machine parameter qemu-kvm-migration for live migrate compatibility with qemu-kvm

This patch series adds inbound migrate capability from qemu-kvm version 1.0. The main ideas are those set out in Cole Robinson's patch here: http://pkgs.fedoraproject.org/cgit/qemu.git/tree/0001-Fix-migration-from-... however, rather than patching statically (and breaking inbound migration on existing machine types), I have added a new machine parameter (qemu-kvm-migration) which when turned on affects the pc-1.0 machine type. Usage: -machine pc-1.0,qemu-kvm-migration=on Three aproaches are taken: * cirrus-vga.vgamem_mb defaults to 16 rather than 8. In order to keep -global cirrus-vga.vgamem_mb working even with qemu-kvm-migration=on, this is monkey-patched into the default value of the MachineState structure's compat_props list. * In hw/timer/i8254_common.c, the VMSTATE_UINT32_TEST macro is used to test the version for the irq_disable flags, allowing version 3 or more, or version 2 for an inbound migrate from qemu-kvm (only). * In hw/acpi/piix4.c, qemu-kvm incorrectly uses version 2 for a version 3 structure, causing acpi_load_old to be used. acpi_load_old detects this situation based on the machine type and restarts the attempt to load the vmstate using a customised VMStateDescription. The above cleaner approach is unavailable here. The above monkey-patching must be done between the selection of the MachineClass and the processing of the machine parameters (on the one hand) and the processing of the compat_props list and the globals on the command line. To do this I have added an earlyinit function to MachineState and QEMUMachine. I developed this on qemu 2.0 but have forward ported it (trivially) to master. My testing has been on a VM live-migrated-to-file from Ubuntu Precise qemu-kvm 1.0. I have given this a moderate degree of testing but it could do with more. Note that certain hardware devices (including QXL) will not migrate properly due to a fundamental difference in their internal state between versions. Also note that (as expected) migration from qemu-2.x to qemu-1.0 will not work, even if the machine types are the same. Changes since v1: * Do not use a machine type, use a machine parameter. Alex Bligh (1): Add machine parameter qemu-kvm-migration for live migrate compatibility with qemu-kvm hw/acpi/piix4.c | 47 +++++++++++++++++++++++++++++++++++++++++++++-- hw/core/machine.c | 16 ++++++++++++++++ hw/i386/pc.c | 1 + hw/i386/pc_piix.c | 25 +++++++++++++++++++++++++ hw/timer/i8254_common.c | 11 ++++++++++- include/hw/boards.h | 7 +++++++ vl.c | 7 +++++++ 7 files changed, 111 insertions(+), 3 deletions(-) -- 1.7.9.5