Getting no output on /dev/hvcNN
On Thu, Mar 19, 2015 at 3:15 PM, Daniel P. Berrange <berrange@xxxxxxxxxx> wrote:
On Thu, Mar 19, 2015 at 01:29:37PM +0530, Neel Basu wrote:
> HI!,
>
> I am using virt-manager GUI. There I can add a `Console Device` through
> Add Hardware. I can add a virtio pty WITHOUT restarting the VM. also I get
> a pty allocated to host machine say `/dev/pty/M`
>
> My expectation is this `host:/dev/pty/M` is connected with a
> `guest:/dev/ttyN`. so If I open minicom or screen and write to
> `host:/dev/pty/M` it will be propagated to 'guest:/dev/ttyN'. Is my
> expectation correct ?
>
> If it is correct how will I know what is the guest tty allocated against
> this host pty ?
No, that's not how it works. The <console> devices are exposed to
the guest as /dev/hvcNN devices. Starting with NN==0
as per the dumpxml output
<console type='pty' tty='/dev/pts/1'>
<source path='/dev/pts/1'/>
<target type='serial' port='0'/>
<alias name='serial0'/>
</console>
I expected host:/dev/pts/1 is paired with guest:/dev/hvc0
So I tried to communicate with minicom,echo,cat with these two but I saw no output. what I echo on /dev/pts/1 doesn't pass to /dev/hvc0 or vice verse.
> Similar to console device I can add a Serial device but that requires a
> reboot of the guest VM. However I tried that though I prefer to do it
> without a guest restart.
>
> <serial type='pty'>
> <source path='/dev/pts/1'/>
> <target port='0'/>
> <alias name='serial0'/>
> </serial>
>
> here also I expected host:/dev/pts/1 is paired with /dev/ttyS0 but couldn't
> communicate.
The serial port device supported is a 1990 era ISA bus serial port
so there's no hotplug for that. Only the paravirt consoles can be
hotplugged.
Regards,
Daniel
--
|: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org -o- http://virt-manager.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
_______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
