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@@ -54,6 +54,23 @@ If you want to check both consoles, use '-serial stdio'.
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Multicore is also supported by QEMU via '-smp n' where n is the number of cores
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to instantiate. Note, the maximum supported CPU number in QEMU is 255.
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+U-Boot uses 'distro_bootcmd' by default when booting on x86 QEMU. This tries to
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+load a boot script, kernel, and ramdisk from several different interfaces. For
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+the default boot order, see 'qemu-x86.h'. For more information, see
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+'README.distro'. Most Linux distros can be booted by writing a uboot script.
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+For example, Debian (stretch) can be booted by creating a script file named
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+'boot.txt' with the contents::
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+
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+ setenv bootargs root=/dev/sda1 ro
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+ load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /vmlinuz
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+ load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initrd.img
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+ zboot ${kernel_addr_r} - ${ramdisk_addr_r} ${filesize}
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+
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+Then compile and install it with::
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+
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+ $ apt install u-boot-tools && \
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+ mkimage -T script -C none -n "Boot script" -d boot.txt /boot/boot.scr
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+
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The fw_cfg interface in QEMU also provides information about kernel data,
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initrd, command-line arguments and more. U-Boot supports directly accessing
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these informtion from fw_cfg interface, which saves the time of loading them
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