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 ?
This is what I've tried:
dumpxml returns
<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/ttyS0. so I opened
screen/cat/echo on both sides but could not exchange messages
------
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.
My sole requirement is to have a tty pair in host and guest that can be
used to communicate with each other. I am using qemu-kvm.
Thank You.
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> 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 :|
Getting no output on /dev/hvcNN On Thu, Mar 19, 2015 at 3:15 PM, Daniel P. Berrange <berrange@redhat.com> 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 > :| >