Further followup discussions in list on commit 192a53e concluded that we should be leaving out the USB controller only for i440fx machines as default USB can be used by someone on q35 at random slots. Signed-off-by: Shivaprasad G Bhat <sbhat(a)linux.vnet.ibm.com&gt; --- src/qemu/qemu_domain.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 173f82c..5a9b48b 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -2884,7 +2884,8 @@ qemuDomainDefFormatBuf(virQEMUDriverPtr driver, * with libvirt <= 0.9.4. Limitation doesn't apply to other archs * and can cause problems on PPC64. */ - if (ARCH_IS_X86(def->os.arch) && usb && usb->idx == 0 && usb->model == -1) { + if (ARCH_IS_X86(def->os.arch) && qemuDomainMachineIsI440FX(def) && + usb && usb->idx == 0 && usb->model == -1) { VIR_DEBUG("Removing default USB controller from domain '%s'" " for migration compatibility", def->name); toremove++;