Re: [libvirt] How to connect to console of domain on PowerPC?

5 Feb 2013

Hi Daniel,

Thanks for your comments.
So far there's no device in QEMU to align with chardev on FSL PowerPC platforms like spapr-pty for IBM PSeries.
Maybe it needs patches to QEMU. I'll take deeper investigation on it.

Anyway for LXC instance, it doesn't depend on the syntax.
I can connect to the console if connect a domain with simple shell.
# vi vm1.xml
<domain type='lxc'>
  <name>vm1</name>
  <memory>32768</memory>
  <os>
    <type>exe</type>
    <init>/bin/sh</init>
  </os>
  <vcpu>1</vcpu>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>
    <console type='pty' tty='/dev/pts/3'>
      <source path='/dev/pts/3'/>
      <target port='0'/>
    </console>
  </devices>
</domain>

# virsh -c lxc:/// define vm1.xml
# virsh -c lxc:/// start vm1
Domain vm1 started

# virsh -c lxc:/// console vm1
Connected to domain vm1
Escape character is ^]
sh-4.2# pwd
/
sh-4.2# ps
  PID TTY          TIME CMD
    1 pts/2    00:00:00 sh
    3 pts/2    00:00:00 ps


But can't get any output when connecting domain with a simple private root filesystem.
# vi vm2.xml
<domain type='lxc'>
  <name>vm2</name>
  <memory>25536</memory>
  <os>
    <type>exe</type>
    <init>/sbin/init</init>
  </os>
  <vcpu>1</vcpu>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/libvirt_lxc</emulator>
    <filesystem type='mount'>
      <source dir='/media/ram/vm1-root'/>
      <target dir='/var/lib/libvirt/lxc/rootfs'/>
    </filesystem>
    <interface type='network'>
      <source network='default'/>
    </interface>
    <console type='pty' />
  </devices>
</domain>

# virsh -c lxc:/// define vm2.xml
# virsh -c lxc:/// start vm2
Domain vm2 started

# virsh -c lxc:/// console vm2
Connected to domain vm2
Escape character is ^]


Do you have any suggestion? 

Best Regards,
Olivia

-----Original Message-----
From: Daniel P. Berrange [mailto:berrange@redhat.com] 
Sent: Monday, February 04, 2013 6:19 PM
To: Yin Olivia-R63875
Cc: libvir-list@redhat.com
Subject: Re: [libvirt] How to connect to console of domain on PowerPC?

On Mon, Feb 04, 2013 at 02:22:03AM +0000, Yin Olivia-R63875 wrote:
...
For instance,
/usr/bin/qemu-system-ppc -name demo -M ppce500v2 -enable-kvm -m 256 
-nographic -kernel /media/ram/uImage -initrd /media/ram/ramdisk 
-append "root=/dev/ram rw console=ttyS0,115200" -serial 
tcp::4445,server
Then to run 'telnet 10.193.20.xxx 4445' could connect the guest.
The temporary workaround is not add '-device' string after '-serial' option.
This is wrong. -serial is legacy command line syntax that libvirt should never use for any QEMU released in the last 2 years. New syntax is uses a combination of -device + -chardev.
...
diff -Nur libvirt-0.10.1.orig/src/qemu/qemu_command.c 
libvirt-0.10.1/src/qemu/qemu_command.c

--- libvirt-0.10.1.orig/src/qemu/qemu_command.c 2012-08-30 
15:35:18.000000000 +0530
+++ libvirt-0.10.1/src/qemu/qemu_command.c      2012-10-05 17:19:32.060368755 +0530
@@ -5501,13 +5501,15 @@
                 virCommandAddArg(cmd, devstr);
                 VIR_FREE(devstr);
-                virCommandAddArg(cmd, "-device");
-                if (!(devstr = qemuBuildChrDeviceStr(serial, qemuCaps,
+                if (!STREQ(def->os.arch, "ppc")) {
+                    virCommandAddArg(cmd, "-device");
+                    if (!(devstr = qemuBuildChrDeviceStr(serial, 
+ qemuCaps,
                                                      def->os.arch,
                                                      def->os.machine)))
-                   goto error;
-                virCommandAddArg(cmd, devstr);
-                VIR_FREE(devstr);
+                    goto error;
+                    virCommandAddArg(cmd, devstr);
+                    VIR_FREE(devstr);
+                }
             } else {
                 virCommandAddArg(cmd, "-serial");
                 if (!(devstr = qemuBuildChrArgStr(&serial->source, 
NULL)))
Applying the above patch to libvirt, all the other domain control commands could work except 'virsh console domain'.
# cat >demo.args <<EOF
...
/usr/bin/qemu-system-ppc -name demo -M ppce500v2 -enable-kvm -m 256 
-nographic -kernel /media/ram/uImage -initrd /media/ram/ramdisk 
-append "root=/dev/ram rw console=ttyS0,115200" -serial 
tcp::4445,server -net nic EOF
# vi demo.args
/usr/bin/qemu-system-ppc -name demo -M ppce500v2 -enable-kvm -m 256 
-nographic -kernel /media/ram/uImage -initrd /media/ram/ramdisk 
-append "root=/dev/ram rw console=ttyS0,115200" -serial 
tcp::4445,server -net nic
If you think libvirt has a problem generating command line args, then rather than telling us about some random command line args you've created yourself, please provide the actual args that libvirt has generated. See /var/log/libvirt/qemu/$GUESTNAME.log for those.

Daniel
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