play: wire up stdin to qemu to make serial work

[stapelberg]

With this change:

1. gokrazy’s serial port starts working in qemu,
   i.e. you can press Enter and get a shell prompt.

2. qemu’s monitor key bindings start working,
   i.e. you don’t quit using Ctrl+C, but by using Ctrl+a x

[stapelberg]

@damdo I find myself wishing for an easy way to run gokrazy instances in qemu more and more. Aside from this PR, do you mind if I merged some of gom into a gok qemu subcommand?

[damdo]

Hey @stapelberg, yes for sure, it'd be awesome to have gom into gok, that was my plan all along!
What parts of it would you like to include?
I should be able to help with this in a bit

[stapelberg]

Hey @stapelberg, yes for sure, it'd be awesome to have gom into gok, that was my plan all along!
What parts of it would you like to include?
I should be able to help with this in a bit

Cool!

I think the first milestone I would want to see is a command to build and run the specified gokrazy instance in a VM.

Conceptually, I’d suggest a “vm” subcommand in gok, which can then have its own subcommands. I suggest “run” as the first subcommand. The vm subcommand would be in the “deploy and update” group.

So, gok vm run should build the instance and execute qemu with the right flags. We can then expand from there, but I think that’s the least controversial and most useful thing in the whole VM space.

Out of scope for now: deploying VMs to services, both commerial (e.g. Google Cloud, AWS, Azure) or self-hosted (e.g. Proxmox). We can add that later, perhaps as a command that requires additional installation if you want to target a specific VM service provider (similar to the OCI plugin approach).

[stapelberg]

So, gok vm run should build the instance and execute qemu with the right flags. We can then expand from there, but I think that’s the least controversial and most useful thing in the whole VM space.

FYI, I have submitted a gok vm run implementation with commit gokrazy/tools@b8ffcd4

Next up is including the EFI firmware (like you did) and then we can expand from there :)