Using Serial Port /dev/ttyS0 in domU

[Konstantin <konstantin@xxxxxxxx>]

Hi Xen users,

Has anyone managed to use /dev/ttyS0 in domU successfully?

I tried to add next strings in the VM configuration file without any 
success.
--------------------------------------
irqs = [ 3, 4 ]
ioports = [ "02f8-02ff", "03f8-03ff" ]
--------------------------------------

This is how part of the configuration looks from xl using -d flag using 
only one serial port ttyS0:
------------------------------
        "ioports": [
            {
                "first": 1016,
                "number": 8
            }
        ],
        "irqs": [
            4
        ],
------------------------------

Using PV domU I'm getting IRQ conflicts with already existing 
(callfunc0) and (debug0) with errors like:
------------------------------------------------------------------------------------------
root@pv-domU:~# screen /dev/ttyS0 115200
[   41.158942] genirq: Flags mismatch irq 4. 00000080 (ttyS0) vs. 
00000c00 (debug0)
root@pv-domU:~# screen /dev/ttyS1 115200
[   79.547305] genirq: Flags mismatch irq 3. 00000080 (ttyS1) vs. 
0002cc00 (callfunc0)
------------------------------------------------------------------------------------------
root@domU:~# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
  0:       9975          0          0          0  xen-percpu    -virq    
  timer0
  1:          0          0          0          0  xen-percpu    -ipi     
  spinlock0
  2:       3133          0          0          0  xen-percpu    -ipi     
  resched0
  3:       1053          0          0          0  xen-percpu    -ipi     
  callfunc0
  4:          0          0          0          0  xen-percpu    -virq    
  debug0
  5:        155          0          0          0  xen-percpu    -ipi     
  callfuncsingle0
...
------------------------------------------------------------------------------------------

In HVM domU I don't even see IRQs in the list
----------------------------------------------------------------------------------
root@mon:~# cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
  0:         20          0          0          0   IO-APIC   2-edge      
timer
  1:         59          0          0          0  xen-pirq   
1-ioapic-edge  i8042
  6:          3          0          0          0  xen-pirq   
6-ioapic-edge  floppy
  8:          2          0          0          0  xen-pirq   
8-ioapic-edge  rtc0
  9:          0          0          0          0  xen-pirq   
9-ioapic-level  acpi
 12:       1308          0          0          0  xen-pirq  
12-ioapic-edge  i8042
 14:          0       1386          0          0   IO-APIC  14-edge      
ata_piix
 15:          0          0          0          0   IO-APIC  15-edge      
ata_piix
 48:      32872          0          0          0  xen-percpu    -virq    
  timer0
.....
----------------------------------------------------------------------------------

Is it even supported? Did I miss anything?

--
Konstantin