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Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support
From: |
Zhu Guihua |
Subject: |
Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support |
Date: |
Mon, 26 Jan 2015 10:01:48 +0800 |
On Fri, 2015-01-23 at 11:24 +0100, Alexandre DERUMIER wrote:
> Hello,
>
> I'm currently testing the new cpu unplug features,
> Works fine here with debian guests and kernel 3.14.
>
Thanks for your test.
> But I have notice some small potential bugs, but I'm not sure I'm doing it
> right.
>
> 1)first, to unplug cpu, we need an id for cpu
>
Yes, if you want to unplug cpu, you must have an id for cpu.
> The problem is that the current qemu command line
> -smp 1,sockets=2,cores=1,maxcpus=2
>
> for example, will create 1 cpu on apic-id 0 without any id, so we can't
> unplug it.
>
>
> So, I have tried with
>
> -smp 1,sockets=2,cores=1,maxcpus=2 -device kvm64-x86_64-cpu,apic-id=0,id=cpu0
>
> But this give me an error:
> "-device kvm64-x86_64-cpu,apic-id=0,id=cpu0: CPU with APIC ID 0 exists"
>
APIC ID 0 was used by the cpu of '-smp 1'.
So you should use apic-id=1
> (also try to set -smp 0, but it's not working).
>
>
>
> 2) second problem, if I start with
> -smp 1,sockets=2,cores=1,maxcpus=2
>
> then hmp:
> device_add kvm64-x86_64-cpu,apic-id=1,id=cpu1
>
> then hmp : device_del cpu1
>
> Got an error:"
> This is the last cpu, should not be removed!"
>
>
Oh, it's our problem, thanks for your pointing out.
I will fix it in next version.
Regards,
Zhu
>
> This is coming from
> [PATCH 06/12] pc: add cpu hot unplug request callback support
> + if (smp_cpus == 1) {
> + error_setg(&local_err,
> + "This is the last cpu, should not be removed!");
> + goto out;
> + }
>
>
>
> So, the only way unplug is working for me, is to start with -smp 2 minimum
> -smp 2,sockets=2,cores=1,maxcpus=4
>
> Then I can hotplug|unplug cpuid >= 2
>
>
>
> Regards,
>
> Alexandre Derumier
[...]
- [Qemu-devel] [PATCH v2 03/11] acpi/piix4: add cpu hot unplug request callback support, (continued)
- [Qemu-devel] [PATCH v2 03/11] acpi/piix4: add cpu hot unplug request callback support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 04/11] acpi/ich9: add cpu hot unplug request callback support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 05/11] pc: add cpu hot unplug request callback support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 06/11] acpi/cpu: add cpu hot unplug callback function, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 07/11] acpi/piix4: add cpu hot unplug callback support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 08/11] acpi/ich9: add cpu hot unplug support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 09/11] pc: add cpu hot unplug callback support, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 10/11] cpu hotplug: implement function cpu_status_write() for vcpu ejection, Zhu Guihua, 2015/01/14
- [Qemu-devel] [PATCH v2 11/11] cpus: reclaim allocated vCPU objects, Zhu Guihua, 2015/01/14
- Message not available
- Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support, Alexandre DERUMIER, 2015/01/23
- Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support, Zhu Guihua, 2015/01/25
- Message not available
- Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support, Alexandre DERUMIER, 2015/01/26
- Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support, Zhu Guihua, 2015/01/26
- Re: [Qemu-devel] [PATCH v2 00/11] cpu: add i386 cpu hot remove support, Bharata B Rao, 2015/01/27