Messages in this thread | | | Date | Wed, 13 Sep 2023 08:38:51 +1000 | Subject | Re: [RFC PATCH 00/32] ACPI/arm64: add support for virtual cpuhotplug | From | Gavin Shan <> |
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Hi James,
On 9/13/23 03:01, James Morse wrote: > On 29/03/2023 03:35, Gavin Shan wrote: >> On 2/3/23 9:50 PM, James Morse wrote: > >>> If folk want to play along at home, you'll need a copy of Qemu that supports this. >>> https://github.com/salil-mehta/qemu.git >>> salil/virt-cpuhp-armv8/rfc-v1-port29092022.psci.present >>> >>> You'll need to fix the numbers of KVM_CAP_ARM_HVC_TO_USER and KVM_CAP_ARM_PSCI_TO_USER >>> to match your host kernel. Replace your '-smp' argument with something like: >>> | -smp cpus=1,maxcpus=3,cores=3,threads=1,sockets=1 >>> >>> then feed the following to the Qemu montior; >>> | (qemu) device_add driver=host-arm-cpu,core-id=1,id=cpu1 >>> | (qemu) device_del cpu1 >>> >>> >>> This series is based on v6.2-rc3, and can be retrieved from: >>> https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/ virtual_cpu_hotplug/rfc/v1 > >> I give it a try, but the hot-added CPU needs to be put into online >> state manually. I'm not sure if it's expected or not. > > This is expected. If you want the CPUs to be brought online automatically, you can add > udev rules to do that. >
Yeah, I usually execute the following command to bring the CPU into online state, after the vCPU is hot added by QMP command.
(qemu) device_add driver=host-arm-cpu,core-id=1,id=cpu1 guest# echo 1 > /sys/devices/system/cpu/cpux/online
James, the series was posted a while ago and do you have plan to respin and post RFCv2 in near future? :)
Thanks, Gavin
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