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=0
I 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 cpu
As 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=0
I 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
