Netboot EFI Linux (diskless) with qemu/ovmf/grub2

. prerequiresites:

- DHCP/TFTP, so that you can netboot with PXE;

1) create an standalone grub efi image:

  sudo grub2-mkstandalone -d /usr/lib/grub/x86_64-efi/ -O x86_64-efi --fonts="unicode" -o grub2.efi  /boot/grub/grub.cfg=/tftpboot/netgrub.cfg

netgrub.cfg is something like:

 set timeout=5

# linux (tftp)/vmlinuz
menuentry 'Linux diskless' --class gentoo --class gnu-linux --class gnu --class os {
        insmod net
        insmod efinet
        insmod tftp
        insmod http
        insmod gzio
        insmod part_gpt

        insmod efi_gop
        insmod efi_uga


        set net_default_server=192.168.1.1

        net_add_addr eno0 efinet0 192.168.1.81

        echo 'Network status: '
        net_ls_cards
        net_ls_addr
        net_ls_routes

        echo 'Loading Linux ...'
        linux (tftp)/vmlinuz root=/dev/nfs rw nfsroot=192.168.1.11:/exports/nfs/gentoo ip=on
}

and let DHCP server send grub2.efi (filename=grub2.efi) to our client (192.168.1.81).

2) build OVMF from EDK2.

3) running a recent qemu (>= 1.6.0)

  sudo qemu-system-x86_64 -enable-kvm -m 2048 -vga qxl -L . -bios OVMF.fd -device virtio-net-pci,romfile=,netdev=mynet0,mac=00:12:34:56:78:9a -netdev tap,script=/etc/qemu/qemu-ifup,id=mynet0 -vnc :30

- Because we use macaddr above, need make sure DHCP server configure macaddr from above to ip address 192.168.1.81.
- Make sure romfile is empty, which will use OVMF virtio-net-pci driver instead of iPXE virtio-net-pci driver (in my case it runs into error: failure at drivers/bus/virtio-ring.c:69)

4) vncview :30 and check status.

Note:

a) In theory this can also boot a box supports PXE into EFI mode (diskless), so that you don't have to create a EFI boot disk (I don't like this way).

dmesg from booted linux with above method:

http://pastebin.com/84xEtwMS