qemu/qom
Bharata B Rao b7bca73334 cpu: Convert cpu_index into a bitmap
Currently CPUState::cpu_index is monotonically increasing and a newly
created CPU always gets the next higher index. The next available
index is calculated by counting the existing number of CPUs. This is
fine as long as we only add CPUs, but there are architectures which
are starting to support CPU removal, too. For an architecture like PowerPC
which derives its CPU identifier (device tree ID) from cpu_index, the
existing logic of generating cpu_index values causes problems.

With the currently proposed method of handling vCPU removal by parking
the vCPU fd in QEMU
(Ref: http://lists.gnu.org/archive/html/qemu-devel/2015-02/msg02604.html),
generating cpu_index this way will not work for PowerPC.

This patch changes the way cpu_index is handed out by maintaining
a bit map of the CPUs that tracks both addition and removal of CPUs.

The CPU bitmap allocation logic is part of cpu_exec_init(), which is
called by instance_init routines of various CPU targets. Newly added
cpu_exec_exit() API handles the deallocation part and this routine is
called from generic CPU instance_finalize.

Note: This new CPU enumeration is for !CONFIG_USER_ONLY only.
CONFIG_USER_ONLY continues to have the old enumeration logic.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
[AF: max_cpus -> MAX_CPUMASK_BITS]
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-07-09 15:20:40 +02:00
..
Makefile.objs add optional 2nd stage initialization to -object/object-add commands 2014-01-28 12:47:02 -05:00
container.c Make all static TypeInfos const 2013-01-10 15:11:53 -06:00
cpu.c cpu: Convert cpu_index into a bitmap 2015-07-09 15:20:40 +02:00
object.c qerror: Clean up QERR_ macros to expand into a single string 2015-06-22 18:20:40 +02:00
object_interfaces.c qom: Add can_be_deleted callback to UserCreatableClass 2015-04-01 10:06:38 +02:00
qom-qobject.c qom: move include files to include/qom/ 2012-12-19 08:31:32 +01:00