Re: [Qemu-devel] [PATCH qom v4 2/7] cpus: Convert cpu_index into a bitmap

["Andreas Färber" <afaerber@suse.de>]

s/cpus/cpu/

Am 24.06.2015 um 15:53 schrieb Andreas Färber:
> Am 24.06.2015 um 04:31 schrieb Peter Crosthwaite:
>> From: Bharata B Rao <bharata@linux.vnet.ibm.com>
>>
>> Currently CPUState.cpu_index is monotonically increasing and a newly

CPUState::cpu_index

>> 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().

(Here it's in TypeInfo:: actually.)

>>
>> 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>
>> ---
>>  exec.c            | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
>>  include/qom/cpu.h |  1 +
>>  qom/cpu.c         |  7 +++++++
>>  3 files changed, 58 insertions(+), 5 deletions(-)
> 
> Doesn't apply on my tree, trying manually...

Caused by exec.c -> qom/cpu.c code movements from Eduardo in my queue.

Applied to qom-cpu.

Thanks,
Andreas

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