---
-QEMU x86 target instructions for bare mode:
-
-To build u-boot.rom for QEMU x86 targets, just simply run
-
-$ make qemu-x86_defconfig (for 32-bit)
-or
-$ make qemu-x86_64_defconfig (for 64-bit)
-$ make all
-
-Note this default configuration will build a U-Boot for the QEMU x86 i440FX
-board. To build a U-Boot against QEMU x86 Q35 board, you can change the build
-configuration during the 'make menuconfig' process like below:
-
-Device Tree Control --->
- ...
- (qemu-x86_q35) Default Device Tree for DT control
-
-Test with QEMU for bare mode
-----------------------------
-QEMU is a fancy emulator that can enable us to test U-Boot without access to
-a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
-U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows:
-
-$ qemu-system-i386 -nographic -bios path/to/u-boot.rom
-
-This will instantiate an emulated x86 board with i440FX and PIIX chipset. QEMU
-also supports emulating an x86 board with Q35 and ICH9 based chipset, which is
-also supported by U-Boot. To instantiate such a machine, call QEMU with:
-
-$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -M q35
-
-Note by default QEMU instantiated boards only have 128 MiB system memory. But
-it is enough to have U-Boot boot and function correctly. You can increase the
-system memory by pass '-m' parameter to QEMU if you want more memory:
-
-$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024
-
-This creates a board with 1 GiB system memory. Currently U-Boot for QEMU only
-supports 3 GiB maximum system memory and reserves the last 1 GiB address space
-for PCI device memory-mapped I/O and other stuff, so the maximum value of '-m'
-would be 3072.
-
-QEMU emulates a graphic card which U-Boot supports. Removing '-nographic' will
-show QEMU's VGA console window. Note this will disable QEMU's serial output.
-If you want to check both consoles, use '-serial stdio'.
-
-Multicore is also supported by QEMU via '-smp n' where n is the number of cores
-to instantiate. Note, the maximum supported CPU number in QEMU is 255.
-
-The fw_cfg interface in QEMU also provides information about kernel data,
-initrd, command-line arguments and more. U-Boot supports directly accessing
-these informtion from fw_cfg interface, which saves the time of loading them
-from hard disk or network again, through emulated devices. To use it , simply
-providing them in QEMU command line:
-
-$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024 -kernel /path/to/bzImage
- -append 'root=/dev/ram console=ttyS0' -initrd /path/to/initrd -smp 8
-
-Note: -initrd and -smp are both optional
-
-Then start QEMU, in U-Boot command line use the following U-Boot command to
-setup kernel:
-
- => qfw
-qfw - QEMU firmware interface
-
-Usage:
-qfw <command>
- - list : print firmware(s) currently loaded
- - cpus : print online cpu number
- - load <kernel addr> <initrd addr> : load kernel and initrd (if any) and setup for zboot
-
-=> qfw load
-loading kernel to address 01000000 size 5d9d30 initrd 04000000 size 1b1ab50
-
-Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then,
-'zboot' can be used to boot the kernel:
-
-=> zboot 01000000 - 04000000 1b1ab50
-
-To run 64-bit U-Boot, qemu-system-x86_64 should be used instead, e.g.:
-$ qemu-system-x86_64 -nographic -bios path/to/u-boot.rom
-
-A specific CPU can be specified via the '-cpu' parameter but please make
-sure the specified CPU supports 64-bit like '-cpu core2duo'. Conversely
-'-cpu pentium' won't work for obvious reasons that the processor only
-supports 32-bit.
-
-Note 64-bit support is very preliminary at this point. Lots of features
-are missing in the 64-bit world. One notable feature is the VGA console
-support which is currently missing, so that you must specify '-nographic'
-to get 64-bit U-Boot up and running.
-
CPU Microcode
-------------
Modern CPUs usually require a special bit stream called microcode [8] to be
projects / oweals / u-boot.git / blobdiff