[CentOS] CentOS 7 kernel console under KVM?

Chris Adams
Wed, 08 Oct 2014 20:06:06 -0000

Once upon a time, Chris Adams <linux at cmadams.net>
said:
> Is there a way to get GRUB2 and the kernel to run a "serial"
console
> under KVM?

So, I guess the people who replied didn't read - I tried ttyS0, and that
didn't work.

I did figure out why that doesn't work: when setting up a new VM with
libvirt in F20, if you choose RHEL7 as the guest OS, it gets set up
differently than RHEL6.  One difference is that it sets up a virtio
console, instead of a serial console.

First, it doesn't look like GRUB2 can talk to a virtio console.

Second, I guess I'm hitting a kernel bug, because the kernel should be
able to talk to a virtio console (i.e. hvc0).  It certainly shouldn't
crash because I tried to use that.  The device works after boot (I can
run a getty on it), it seems only the kernel can't talk to it directly
as a console.

--
Chris Adams <linux at cmadams.net>