Hi,
I am looking into QEMU code in ARM recently and trying to add add_hot_cpu in QEMU for ARM,
but it doesn't work when enabling KVM. It reports error:
"kvm_init_vcpu failed: Device or resourc busy."
By debugging QEMU with gdb, it failed on ioctl. In kernel soruce code arch/arm/kvm/arm.c,
vcpu is created by this following function, it will report -EBUSY if irqchip_in_kernel.
struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
{
int err;
struct kvm_vcpu *vcpu;
if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) {
err = -EBUSY;
goto out;
}
....
}
I set virt machine with kernel_irqchip = off, it can execute cpu-add interface correctly with qmp-shell
commands. But VMs still can't work well with kernel_irqchip=off when executing "info cpus" in qemu monitor.
My question is that:
1) Can we change this error status in kvm_arch_vcpu_create?
2) Is it that irqchip_kernel=off isn't supported with KVM enabled on ARM?