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qemu / qboot / refs/heads/github/fork/osresearch/makefile
commit9d99185de6e39e963787593d45143c42b2e0a66a[log] [tgz]
authorTrammell hudson <hudson@trmm.net>Fri Mar 13 16:38:30 2020 +0100
committerTrammell hudson <hudson@trmm.net>Fri Mar 13 16:38:30 2020 +0100
treee33ff109c1234a5417cec09fe8bec704806f8e86
parent7aeec271d806efe1ecc18bf6dc32f39dfe8b994a [diff]
readme: markdown formatting

Signed-off-by: Trammell hudson <hudson@trmm.net>
1 file changed
tree: e33ff109c1234a5417cec09fe8bec704806f8e86
  1. .github/
  2. include/
  3. .gitignore
  4. benchmark.h
  5. code16.c
  6. code32seg.c
  7. cstart.S
  8. entry.S
  9. flat.lds
  10. fw_cfg.c
  11. hwsetup.c
  12. LICENSE
  13. linuxboot.c
  14. main.c
  15. Makefile
  16. malloc.c
  17. mptable.c
  18. pci.c
  19. printf.c
  20. README.md
  21. smbios.c
  22. string.c
  23. tables.c
README.md

Build status

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 https://github.com/bonzini/qboot.git

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

$ make

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

Usage

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

TODO

  • Add the possibility to configure out PIC and PCI bridge initialization