Skip to content
Minimal x86 firmware for booting Linux kernels
C Assembly Makefile C++
Branch: master
Clone or download
bonzini remove pflash code
Also part of the cbfs support which is now obsolete.

Signed-off-by: Paolo Bonzini <>
Latest commit cb1c49e Jul 25, 2019


A simple x86 firmware that can boot Linux.

Most of QEMU's startup time is spent:

* in the dynamic linker.  This can be reduced by 150 ms simply by
  compiling a stripped down QEMU:

    ./configure --disable-libssh2 --disable-tcmalloc --disable-glusterfs \
        --disable-seccomp --disable-{bzip2,snappy,lzo} --disable-usb-redir \
        --disable-libusb --disable-smartcard-nss --disable-libnfs  \
        --disable-libiscsi --disable-rbd  --disable-spice --disable-attr \
        --disable-cap-ng --disable-linux-aio --disable-brlapi \
        --disable-vnc-{jpeg,tls,sasl,png,ws} --disable-rdma --disable-bluez \
        --disable-fdt --disable-curl --disable-curses --disable-sdl \
        --disable-gtk  --disable-tpm --disable-vte --disable-vnc  \
        --disable-xen --disable-opengl --target-list=x86_64-softmmu

* in the BIOS.  qboot saves another 150 ms.

* until QEMU 2.7+, in fw_cfg.  qboot uses the DMA interface which is pretty
  much instantaneous.

Compile qboot

Clone the source:

    $ git clone

Compile the qboot firmware (you may need to install the relevant build
time dependancies):

    $ make

The result will be a 64K file named bios.bin.


    $ qemu-kvm -bios bios.bin \
      -kernel /boot/vmlinuz-4.0.3-300.fc22.x86_64 \
      -serial mon:stdio -append 'console=ttyS0,115200,8n1'


* SMBIOS tables
* Add the possibility to configure out PIC and PCI bridge initialization
You can’t perform that action at this time.