Implement Virt-io Console device.

[basicer]

Implements a virtio console device. This allows reading and writing buffers in bulk as well as a channel to communicate terminal size updates.

[copy]

Thanks! This is useful to check the existing virtio implemention, and eventually could serve as a better console for some of the modern OSes.

I have left a few stylistic remarks, but overall this looks good.

I've tested this on the archlinux profile and the device is detected and seems to work.

If you rebase, the test failure should go away.

What's missing (not necessarily in this PR):

• A test. Unfortunately the small Linux images haven't been configured with virtio-console support, so this will have to wait for later
• Integration into xtermjs (e.g. a virtio_console_container_xtermjs parameter, analogous to serial_container_xtermjs)
• Some documentation on how to use this, at least on Linux

[basicer]

Thanks for the feedback. I'll get the style cleaned up. For testing I made a custom Alpine Linux based image that weights about 26mb (6mb kernel, 20mb initramfs). Would a test based on that work, or is it still a bit too large?

[copy]

For testing I made a custom Alpine Linux based image that weights about 26mb (6mb kernel, 20mb initramfs). Would a test based on that work, or is it still a bit too large?

Yes, that would be useful.

[copy]

Thanks! I've added a test in 609d794