qemu -m 1G -kernel ipxe.lkrn
The program 'qemu' can be found in the following packages:
 * qemu-system-arm
 * qemu-system-mips
 * qemu-system-misc
 * qemu-system-ppc
 * qemu-system-sparc
 * qemu-system-x86
Try: sudo apt-get install <selected package>