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From: | Dou Liyang |
Subject: | Re: [Qemu-devel] [PATCH v7] docs: add cpu-hotplug.txt |
Date: | Wed, 7 Sep 2016 09:52:59 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
Hi, Eduardo At 09/07/2016 04:05 AM, Eduardo Habkost wrote:
On Tue, Aug 23, 2016 at 01:17:01PM +0800, Dou Liyang wrote:Hi Alexandre, At 08/22/2016 04:56 PM, Alexandre DERUMIER wrote:Hello, I'm looking to implement cpu hotplug, and I have a question about cpu flags currently I have something like -cpu qemu64,+lahf_lm,+sep,+kvm_pv_unhalt,+kvm_pv_eoi,enforce -smp 4,sockets=2,cores=2,maxcpus=4 Does I need to define flags like: -smp 2,sockets=2,cores=2,maxcpus=4 -device qemu64-x86_64-cpu,+lahf_lm,+sep,+kvm_pv_unhalt,+kvm_pv_eoi,enforce,id=cpu1,socket-id=1,core-id=1,thread-id=0I think we don't need to do that. In my option, just like this: -device qemu64-x86_64-cpu,id=cpu1,socket-id=1,.. Because QEMU sets the "-cpu" options in MachineState: current_machine->cpu_model = cpu_model; when you add a CPU, QEMU can get the flag from the MachineState.You don't need to repeat the flags, but that's not because of MachineState::cpu_model, but because of the semantics of -smp:
Sorry for the reply.
The option: -smp MODEL,+FOO,+BAR
I guess you may mean "-cpu", not "-smp"
is internally translated to: -global MODEL.FOO=on -global MODEL.BAR=on in addition to setting the CPU model for creating initial CPUs to MODEL.
I see.
... ? Another question, is -smp mandatory ? (if I want coldplug all cpus)it's not mandatory. such as this: ./x86_64-softmmu/qemu-system-x86_64 -m 1G /image/fedora.img -enable-kvm -monitor stdio (qemu) info cpus * CPU #0: pc=0xffffffff81060586 (halted) thread_id=4032 the default number of CPUs is 1.-smp sockets=2,cores=2,maxcpus=4-device qemu64-x86_64-cpu,id=cpu1,socket-id=1,core-id=1,thread-id=0 -device qemu64-x86_64-cpu,id=cpu1,socket-id=1,core-id=2,thread-id=0 -device qemu64-x86_64-cpu,id=cpu3,socket-id=2,core-id=1,thread-id=0 -device qemu64-x86_64-cpu,id=cpu4,socket-id=2,core-id=2,thread-id=0 or does I need minimum 1 non unplugable cpuAs mentioned above, the default number of CPUs is 1, so "-smp sockets=2" is the same as "-smp 1,sockets=2". I assume you mean something like "-smp 0", but that doesn't work today. I would like to eventually allow all CPUs to be created using -device, but that's not possible yet.
I am interested in what is the benefit, if we can create all CPUs using -device. :) Thanks, Dou
-smp 1,sockets=2,cores=2,maxcpus=4 -device qemu64-x86_64-cpu,id=cpu1,socket-id=1,core-id=2,thread-id=0 -device qemu64-x86_64-cpu,id=cpu3,socket-id=2,core-id=1,thread-id=0 -device qemu64-x86_64-cpu,id=cpu4,socket-id=2,core-id=2,thread-id=0I think that is better, and the socket-id/core-id/thread-id starts at index 0 I am new to the community. Please don't mind, and take with a grain of salt. Thanks, Dou
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