Comment 13 for bug 1246929

http://git.kernel.org/cgit/virt/kvm/qemu-kvm.git/plain/hw/ac97.c

the emulated ac97 emulate 82801AA (ICH)

static void ac97_class_init (ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS (klass);
    PCIDeviceClass *k = PCI_DEVICE_CLASS (klass);

    k->init = ac97_initfn;
    k->exit = ac97_exitfn;
    k->vendor_id = PCI_VENDOR_ID_INTEL;
    k->device_id = PCI_DEVICE_ID_INTEL_82801AA_5;
    k->revision = 0x01;
    k->class_id = PCI_CLASS_MULTIMEDIA_AUDIO;

the emulated HDA emulate 82801FB (ICH6)

http://git.kernel.org/cgit/virt/kvm/qemu-kvm.git/plain/hw/intel-hda.c

static void intel_hda_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);

    k->init = intel_hda_init;
    k->exit = intel_hda_exit;
    k->vendor_id = PCI_VENDOR_ID_INTEL;
    k->device_id = 0x2668;
    k->revision = 1;
    k->class_id = PCI_CLASS_MULTIMEDIA_HD_AUDIO;
    dc->desc = "Intel HD Audio Controller";