On Wed, Jul 12, 2023 at 5:26 AM Glenn Washburn <[email protected]> wrote: > > On Sat, 8 Jul 2023 19:58:29 +0800 > Hongyi Zhao <[email protected]> wrote: > > > Hi here, > > > > Are there some convenient methods to debug grub scripts without > > rebooting into grub shell? > > I would recommend running the GRUB EFI application in QEMU, as it will act > more closely to when running on bare metal. Here's an example of a QEMU > command that I use when doing development: > > qemu-system-x86_64 -name '[x86_64-efi] Test Grub' \ > -m 2048 -bios OVMF.fd --enable-kvm -boot once=c,menu=on \ > -nodefaults -rtc base=localtime -vga std -snapshot \ > -drive file=/home/grub-tester/bootloader/efidisk.img,format=raw \ > -device virtio-scsi-pci,id=scsi0,num_queues=4 \ > -device > scsi-hd,drive=drive0,id=systema,bus=scsi0.0,scsi-id=0,lun=0,channel=0 \ > -drive file=/dev/sdc,format=raw,if=none,id=drive0,readonly=on \ > -device > scsi-hd,drive=drive1,id=systemb,bus=scsi0.0,scsi-id=0,lun=1,channel=0 \ > -drive file=/home/user/disk.img,format=raw,if=none,id=drive1,readonly=on > > If you want to use a block device, then you'll need to run as root or > otherwise have correct permissions to read from the device. But you can have > everything in a disk image file and not need to run as root.
I tried to adapt your approach to my case, but it didn't work: werner@X10DAi:/media/werner/a5d0e46f-aea7-43f0-9a3e-cfb6d517d214/EFI/grub-mkstandalone$ sudo qemu-system-x86_64 -name '[x86_64-efi] Test Grub' -m 2048 -bios OVMF.fd --enable-kvm -boot once=c,menu=on -nodefaults -rtc base=localtime -vga std -snapshot -drive file=./grubx64.efi,format=raw -device virtio-scsi-pci,id=scsi0,num_queues=4 -device scsi-hd,drive=drive0,id=systema,bus=scsi0.0,scsi-id=0,lun=0,channel=0 -drive file=/dev/sdc,format=raw,if=none,id=drive0,readonly=on -device scsi-hd,drive=drive1,id=systemb,bus=scsi0.0,scsi-id=0,lun=1,channel=0 format=raw,if=none,id=drive1,readonly=on qemu-system-x86_64: -drive file=/dev/sdc,format=raw,if=none,id=drive0,readonly=on: Could not open '/dev/sdc': No such file or directory > Also You can add the options "--nographic -serial stdio" to have the interface > be via serial, which allows text selection. In this case GRUB will need to be > configured to output to serial. > > Glenn Zhao
