1 files changed, 80 insertions, 0 deletions
diff --git a/qemu/roms/seabios/docs/Build_overview.md b/qemu/roms/seabios/docs/Build_overview.md
new file mode 100644
index 000000000..26db22691
--- /dev/null
+++ b/qemu/roms/seabios/docs/Build_overview.md
@@ -0,0 +1,80 @@
+The SeaBIOS code can be built using standard GNU tools. A recent Linux
+distribution should be able to build SeaBIOS using the standard
+compiler tools.
+
+Building SeaBIOS
+================
+
+First, [obtain the code](Download). SeaBIOS can be compiled for
+several different build targets. It is also possible to configure
+additional compile time options - run **make menuconfig** to do this.
+
+Build for QEMU (along with KVM, Xen, and Bochs)
+-----------------------------------------------
+
+To build for QEMU (and similar), one should be able to run "make" in
+the main directory. The resulting file "out/bios.bin" contains the
+processed bios image.
+
+One can use the resulting binary with QEMU by using QEMU's "-bios"
+option. For example:
+
+`qemu -bios out/bios.bin -fda myfdimage.img`
+
+One can also use the resulting binary with Bochs. For example:
+
+`bochs -q 'floppya: 1_44=myfdimage.img' 'romimage: file=out/bios.bin'`
+
+Build for coreboot
+------------------
+
+To build for coreboot please see the coreboot build instructions at:
+<http://www.coreboot.org/SeaBIOS>
+
+Build as a UEFI Compatibility Support Module (CSM)
+--------------------------------------------------
+
+To build as a CSM, first run kconfig (make menuconfig) and enable
+CONFIG_CSM. Then build SeaBIOS (make) - the resulting binary will be
+in "out/Csm16.bin".
+
+This binary may be used with the OMVF/EDK-II UEFI firmware. It will
+provide "legacy" BIOS services for booting non-EFI operating systems
+and will also allow OVMF to display on otherwise unsupported video
+hardware by using the traditional VGA BIOS. (Windows 2008r2 is known
+to use INT 10h BIOS calls even when booted via EFI, and the presence
+of a CSM makes this work as expected too.)
+
+Having built SeaBIOS with CONFIG_CSM, one should be able to drop the
+result (out/Csm16.bin) into an OVMF build tree at
+OvmfPkg/Csm/Csm16/Csm16.bin and then build OVMF with 'build -D
+CSM_ENABLE'. The SeaBIOS binary will be included as a discrete file
+within the 'Flash Volume' which is created, and there are tools which
+will extract it and allow it to be replaced.
+
+Overview of files in the repository
+===================================
+
+The **src/** directory contains the main bios source code. The
+**src/hw/** directory contains source code specific to hardware
+drivers. The **src/fw/** directory contains source code for platform
+firmware initialization. The **src/std/** directory contains header
+files describing standard bios, firmware, and hardware interfaces.
+
+The **vgasrc/** directory contains code for VGA BIOS implementations.
+This code is separate from the main BIOS code in the src/ directory.
+When the build is configured to produce a VGA BIOS the resulting
+binary is found in out/vgabios.bin. The VGA BIOS code is always
+compiled in 16bit mode.
+
+The **scripts/** directory contains helper utilities for manipulating
+and building the final roms.
+
+The **out/** directory is created by the build process - it contains
+all intermediate and final files.
+
+When reading the C code be aware that code that runs in 16bit mode can
+not arbitrarily access non-stack memory - see [Memory Model](Memory
+Model) for more details. For information on the major C code functions
+and where code execution starts see [Execution and code
+flow](Execution and code flow).