On Monday, 24 May 2021 02:01:15 BST Oliver Dixon wrote: > Hi, > > I decided to bite the bullet yesterday and switch from clunky, and generally > untoward, VirtualBox to QEMU/KVM for developing kernel modules. I have a > working Gentoo VM with all the bells and whistles I need/want (UEFI > booting, NIC passthrough, SSH forwarding, NFSv4 support, etc.), but it's > running in an SDL window, which means the guest TTY will become confused > and pretty much unusable whenever I change the window size. (Which is > rather often since I use a tiling window manager.)
Have you tried '-display sdl,gl=on -vga virtio' and then use Ctrl+Alt+f to maximise it early in the boot process? It seems to work OK here, without distorting the contents of the VM window. > Since I'll only be using the TTY, the '-nographic' option to QEMU seems > appropriate, but this causes the initial bootloader screen (OVMF/EDK-II) and > GRUB to hang on stdout (screenshot attached). Here's my QEMU invocation > script: > > #!/bin/bash > > exec qemu-system-x86_64 \ > -enable-kvm \ > -cpu host \ > -drive file=Gentoo-VM.img,if=virtio \ > -nic user,hostfwd=tcp:127.0.0.1:2222-:22 \ > -m 4G \ > -smp 12 \ > -name "Gentoo VM" \ > -bios /usr/share/edk2-ovmf/OVMF_CODE.fd \ > -nographic \ > $@ > > I have to spawn another terminal to kill the QEMU process. I can make a bit > of progress by telling the kernel to direct early messages to ttyS0, which > does display the early bootup messages from Linux, but then hangs just > before a login prompt would be shown (screenshot attached). > > console=tty0 console=ttyS0,9600n8 > > Again, I can't do anything other than a `pkill qemu` from elsewhere. > > Any ideas from someone more familiar with QEMU hosting Linux guests? I've > only been using it for a day, most of which has been trying to fix this > annoying behaviour. > > Cheers. As far as I understand it (haven't tried it) you'll need to redirect the virtual console of the guest to the host. Also configure GRUB to do the same. For GRUB you'll probably need: GRUB_TIMEOUT_STYLE=menu GRUB_CMDLINE_LINUX="console=ttyS0" GRUB_TERMINAL="console serial" For the guest kernel command line you can append console=ttyS0. Theoretically it should arrive at a login prompt on your terminal. For testing kernels have a look here: https://qemu-project.gitlab.io/qemu/system/linuxboot.html To shut down the guest you could try using the QEMU monitor (Ctrl+Alt+2) and run 'system_powerdown', or Ctrl+Alt+3 for the serial port.
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