On Fri, 8 May 2015 09:07:18 +1000 Paul Mackerras <paulus@xxxxxxxxx> wrote: > On Thu, May 07, 2015 at 05:49:39PM +0200, Thomas Huth wrote: > > Both functions are doing the same thing - looking up the struct > > kvm_vcpu pointer for a given vCPU ID. > > No, kvm_get_vcpu(n) returns the n'th vcpu created, which is often > but not necessarily the same as the vcpu with id n. In fact, due to > the way we do threading in HV KVM, it's quite common for userspace to > create vcpus with ids 0, 8, 16, ..., which means that the n'th vcpu > created does not have id n (except of course for vcpu 0). Ah, ok, thanks a lot for the explanation ... I thought that KVM would always put the VCPUs at the position of their ID into the array, but looking at kvm_vm_ioctl_create_vcpu(), you're right, it's using the amount of online CPUs as index instead: kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu; So never mind, and sorry for the nuisance! Thomas -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
