Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support

[Bharata B Rao]

On Tue, Jan 27, 2015 at 7:30 AM, Zhu Guihua <address@hidden> wrote:
> On Mon, 2015-01-26 at 12:27 +0100, Alexandre DERUMIER wrote:
>> >>About this, I can do it successfully on my qemu.
>> >>So can you tell us more information about your operation?
>> simply start with
>>
>> -smp 2,sockets=2,cores=2,maxcpus=4 -device kvm64-x86_64-cpu,apic-id=2,id=cpu2
>>
>> then
>>
>> #device_del cpu2
>>
>> Guest return
>> [  324.195024] Unregister pv shared memory for cpu 2
>> [  324.250579] smpboot: CPU 2 is now offline
>>
>> but cpu is not remove in qemu.
>>
>> I had also try to eject manualy from guest
>> echo 1 > /sys/bus/acpi/devices/LNXCPU\:02/eject
>>
>> But I have this error message
>> ACPI: \_SB_.CP02: Eject incomplete - status 0xf
>>
>> (maybe is it normal ? or maybe is it a guest bug (kernel 3.16 from debian 
>> wheezy backports) ?)
>>
>
> According to your description, the guest has invoked _EJ0 method, but
> the method was executed unsuccessfully.
> Thus, only hot-unplug request was invoked in qemu, but hot-unplug was
> not so that cpu was still in qemu.
>
> Did you test any other kernel version? I will try kernel 3.16 to
> investigate this problem later.

Not sure if it is exactly same, but I had similar problem as seen by
Alexandre when I had tried this patchset earlier and it was resolved
by using iasl and regenerating the ACPI tables.

Ref: http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg02993.html

Regards,
Bharata.