Re: Building grub2 for use as a kernel on qemu

[Andrei Borzenkov]

03.02.2017 23:49, Shaun Reitan пишет:
> Andrei,
> 
> Tried to build a kernel image using the following.
> 
> ./bin/grub-mkstandalone -O i386-pc -o grub2.img grub.cfg --fonts=""
> --locales="" --themes="" --install-modules="acpi adler32 affs ahci
> all_video aout ata at_keyboard biosdisk blocklist boot bufio cat cbfs
> cbls cbmemc cbtable cbtime chain cmosdump cmp configfile cpio_be cpio
> cpuid crc64 cryptodisk crypto date datetime diskfilter disk div div_test
> dm_nv drivemap echo efiemu ehci elf eval exfat exfctest ext2 extcmd fat
> file gettext gfxmenu gfxterm_background gfxterm_menu gfxterm gptsync
> gzio halt hashsum help iorw iso9660 keylayouts keystatus ldm legacycfg
> legacy_password_test linux16 linux loadenv loopback lsacpi lsapm lsmmap
> ls lspci lzopio macbless macho memdisk memrw minicmd mmap morse mpi
> mul_test multiboot2 multiboot nativedisk net newc nilfs2 normal ntldr
> odc offsetio ohci part_gpt password pata pcidump pci priority_queue
> probe procfs random read reboot regexp relocator romfs scsi
> search_fs_file search_fs_uuid search_label search sendkey serial setjmp
> setpci shift_test signature_test sleep syslinuxcfg tar terminal terminfo
> test_blockarg testload test tga time trig tr true udf uhci usb_keyboard
> usb usbms usbtest vbe verify vga vga_text video_cirrus video xfs xzio"
> 
> basically i took every module from the i386-pc/*.mod directory and
> attempted to add it.  The image was too large so i went through the
> module list and removed stuff that i was pretty sure i didnt need.
> 
> When i boot the image, i see nothing but the memdisk, i'm also in that
> same grub2 shell.  I should see a (hd0) along with my (memdisk)
> 

You need to include biosdisk into image (or in memory disk and load
explicitly from grub.cfg). PC BIOS offers alternative disk driver so
this is image-build-time option.

address@hidden:~/build/grub$ echo "insmod biosdisk" > /tmp/grub.cfg
address@hidden:~/build/grub$ pkgdatadir=$PWD ./grub-mkstandalone
-d grub-core -O i386-pc -o grub.img --locales= --themes= --fonts=
--install-modules="all_video boot btrfs cat chain configfile echo ext2
fat font gettext gfxmenu gfxterm gfxterm_background gzio halt hfsplus
iso9660 jpeg keystatus loadenv loopback linux memdisk minicmd normal
part_apple part_msdos part_gpt password_pbkdf2 png reboot search
search_fs_uuid search_fs_file search_label sleep squash4 test true video
zfs zfscrypt zfsinfo biosdisk echo linux linux16 ls"
/boot/grub/grub.cfg=/tmp/grub.cfg

address@hidden:~/build/grub$ qemu-system-x86_64 -m 1G -device
virtio-scsi-pci -drive
file=/home/bor/vm/tw/hd0.img,if=none,id=hd0,discard=on,format=raw
-device scsi-hd,drive=hd0 -drive
file=/home/bor/vm/tw/test1.img,if=virtio,format=raw -drive
file=/home/bor/vm/tw/test2.img,if=virtio,format=raw -net user -net
nic,model=virtio -kernel grub.img

And "ls" in CLI shows me all disks. Of course you also need to manually
load suitable partition drivers to access partitions.

Alternative is to use grub-mkstandalone ... --modules=biosdisk.

May be we should add --disk-module option of grub-install to other high
level tools.

Oh, and $prefix in standalone image is set to (memdisk)/boot/grub, which
means you need to put grub.cfg in /boot/grub if you want it to be
executed automatically; you use graft syntax for this

grub-mkstandalone ... /boot/grub/grub.cfg=/path/to/your/config/file