On Wed, Jun 07, 2023 at 10:26:59AM +0200, Philippe Mathieu-Daudé wrote: > On 7/6/23 04:49, Suravee Suthikulpanit wrote: > > Since KVM_MAX_VCPUS is currently defined to 1024 for x86 as shown in > > arch/x86/include/asm/kvm_host.h, update QEMU limits to the same number. > > > > In case KVM could not support the specified number of vcpus, QEMU would > > return the following error message: > > > > qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (xxx): Invalid > > argument > > Odd, we already check the upper limit with KVM_CAP_NR_VCPUS. > See in kvm_init(): > > /* check the vcpu limits */ > soft_vcpus_limit = kvm_recommended_vcpus(s); > hard_vcpus_limit = kvm_max_vcpus(s); > > When testing your series I get: > > qemu-system-x86_64: -accel kvm: warning: Number of SMP cpus requested (1024) > exceeds the recommended cpus supported by KVM (710) > > $ uname -srvp > Linux 5.15.0-71-generic #78-Ubuntu SMP Tue Apr 18 09:00:29 UTC 2023 x86_64
That's a relatively old kernel. With latest kernels, the 'recommended cpus' limit reported will match the number of CPUs in your host, so for me it always complains for smp > 12. 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 :|
