Comment # 35 on bug 1201994 from James Fehlig

(In reply to Erwin Pacua from comment #34)
> The issue still remains - xl unable to emulate audio device while libvirt
> can.

I'm still unable to reproduce this on a updated Leap15.4 host. I'm using the
same xl config in #31 with a Leap15.4 guest and see the device in the guest

# hwinfo --sound
12: PCI 03.0: 0401 Multimedia audio controller                  
  [Created at pci.386]
  Unique ID: 3hqH.Wvt18xt+7v7
  SysFS ID: /devices/pci0000:00/0000:00:03.0
  SysFS BusID: 0000:00:03.0
  Hardware Class: sound
  Model: "Red Hat QEMU Virtual Machine"
  Vendor: pci 0x8086 "Intel Corporation"
  Device: pci 0x2415 "82801AA AC'97 Audio Controller"
  SubVendor: pci 0x1af4 "Red Hat, Inc."
  SubDevice: pci 0x1100 "QEMU Virtual Machine"
  Revision: 0x01
  Driver: "snd_intel8x0"
  Driver Modules: "snd_intel8x0"
  I/O Ports: 0xc000-0xc3ff (rw)
  I/O Ports: 0xc500-0xc5ff (rw)
  IRQ: 28 (409 events)
  Module Alias: "pci:v00008086d00002415sv00001AF4sd00001100bc04sc01i00"
  Driver Info #0:
    Driver Status: snd_intel8x0 is active
    Driver Activation Cmd: "modprobe snd_intel8x0"
  Config Status: cfg=new, avail=yes, need=no, active=unknown

I'm not sure how to proceed. Have you already tried a fresh install of Leap15.4
Xen host, if that is possible?