On Tue, Nov 15, 2022 at 12:19:35AM +0100, Pawel Polawski wrote: > Hi Everyone, > > I am trying to check qemu virtual cpu boundaries when running a custom > edk2 based firmware build. For that purpose I want to run qemu with more > than 1024 vCPU: > $QEMU > -accel kvm > -m 4G > -M q35,kernel-irqchip=on,smm=on > -smp cpus=1025,maxcpus=1025 -global mch.extended-tseg-mbytes=128 > -drive if=pflash,format=raw,file=${CODE},readonly=on > -drive if=pflash,format=raw,file=${VARS} > -chardev stdio,id=fwlog > -device isa-debugcon,iobase=0x402,chardev=fwlog "$@" > > The result is as follows: > QEMU emulator version 7.0.50 (v7.0.0-1651-g9cc1bf1ebc-dirty) > Copyright (c) 2003-2022 Fabrice Bellard and the QEMU Project developers > qemu-system-x86_64: -accel kvm: warning: Number of SMP cpus requested > (1025) exceeds the recommended cpus supported by KVM (8) > Number of SMP cpus requested (1025) exceeds the maximum cpus supported by > KVM (1024) > > It is not clear to me if I am hitting qemu limitation or KVM limitation > here.
As per the error message, this is a KVM limit. QEMU queries the KVM kernel module for this limit at runtime. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|