pci_find_first_device
bootidx = pci_find_first_device(PCI_PRODUCT_VIRTIO_BLOCK);
bootidx = pci_find_first_device(PCI_PRODUCT_VIRTIO_SCSI);
bootidx = pci_find_first_device(PCI_PRODUCT_VIRTIO_NETWORK);
int pci_find_first_device(uint16_t);