Linux Virtualization - Jun 2014 - Why is virtio_console not a tty?

I have gotten scattered reports of strange problems caused by the fact
that virtio_console doesn't behave like a normal tty (support termios
and so on.)  This seems to be an odd restriction -- is there any
fundamental reason for this design choice?

	-hpa

"H. Peter Anvin" <hpa at zytor.com>
writes:
> I have gotten scattered reports of strange problems caused by the fact
> that virtio_console doesn't behave like a normal tty (support termios
> and so on.)  This seems to be an odd restriction -- is there any
> fundamental reason for this design choice?
Not that I know.  I tacked it into hvc_console which provided the glue
to make it a console.  Avoided me digging into console implementation,
which is pretty horrible.

Given my ignorance, how much change do we need to make it behave like a
TTY?

Cheers,
Rusty.

On 06/12/2014 06:06 PM, Rusty Russell wrote:
> "H. Peter Anvin" <hpa at zytor.com> writes:
>> I have gotten scattered reports of strange problems caused by the fact
>> that virtio_console doesn't behave like a normal tty (support
termios
>> and so on.)  This seems to be an odd restriction -- is there any
>> fundamental reason for this design choice?
> 
> Not that I know.  I tacked it into hvc_console which provided the glue
> to make it a console.  Avoided me digging into console implementation,
> which is pretty horrible.
> 
> Given my ignorance, how much change do we need to make it behave like a
> TTY?
> 
hvc_console.c seems to set up a tty subsystem, so that is really
confusing...

	-hpa