[Qemu-devel] [PATCH v2 0/3] Bitmap based CPU enumeration

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

This patch changes the way cpu_index is handed out to newly created
CPUs by tracking the allocted CPUs in a bitmap. More information and
the need for this patch is described in patch 2/3 of this series. These
generic changes are needed to support CPU hot plug/unplug on PowerPC.

An open question is about handling of holes correctly in the allocated
bitmap to support VM migration after CPU unplug. This was briefly discussed
here:

https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg00560.html

Should cpu_exec_init() API support specifying of a particular cpu_index
in addition to returning the next available cpu_index by default ? I know
that QEMU cmdline semantics for CPU device add/delele haven't been defined
yet, but should we now make provision in cpu_exec_init() to allocate the
required cpu_index ?

Changes in v2
-------------
Following changes to address Eduardo's comments:

- Call cpu_exec_init() from generic CPU::instance_finalize() instead
  of touching all archs.
- Initialize cpu_index to -1 from generic CPU::instance_init().
- Callers of cpu_exec_init() now pass error_abort argument instead of NULL.
- Consolidate the older CPU enumeration code for CONFIG_USER_ONLY under
  cpu_get_free_index().

v1: https://lists.gnu.org/archive/html/qemu-devel/2015-05/msg01385.html
v0: https://lists.gnu.org/archive/html/qemu-devel/2015-03/msg02950.html

Bharata B Rao (3):
  cpus: Add Error argument to cpu_exec_init()
  cpus: Convert cpu_index into a bitmap
  ppc: Move cpu_exec_init() call to realize function

 exec.c                      | 57 ++++++++++++++++++++++++++++++++++++++++-----
 include/exec/exec-all.h     |  2 +-
 include/qom/cpu.h           |  1 +
 qom/cpu.c                   |  7 ++++++
 target-alpha/cpu.c          |  2 +-
 target-arm/cpu.c            |  2 +-
 target-cris/cpu.c           |  2 +-
 target-i386/cpu.c           |  2 +-
 target-lm32/cpu.c           |  2 +-
 target-m68k/cpu.c           |  2 +-
 target-microblaze/cpu.c     |  2 +-
 target-mips/cpu.c           |  2 +-
 target-moxie/cpu.c          |  2 +-
 target-openrisc/cpu.c       |  2 +-
 target-ppc/translate_init.c |  9 +++++--
 target-s390x/cpu.c          |  2 +-
 target-sh4/cpu.c            |  2 +-
 target-sparc/cpu.c          |  2 +-
 target-tricore/cpu.c        |  2 +-
 target-unicore32/cpu.c      |  2 +-
 target-xtensa/cpu.c         |  2 +-
 21 files changed, 83 insertions(+), 25 deletions(-)

-- 
2.1.0