[libvirt] guests and pulseaudio fighting over audio devices

I noticed that when a KVM guest created with virt-manager is running on F10, sound on the physical host stops working. When all VMs are shutdown, sound starts working again. Removing the <sound> tag from the VM XML allows sound to work while the VM is booted. To further complicate troubleshooting, if audio is already playing when the guest is started it keeps playing, since pulse already has the device open. The message in /var/log/messages when I try to play audio is: pulseaudio[6492]: module-alsa-sink.c: Error opening PCM device front:0: Device or resource busy strace of pulseaudio shows: open("/dev/snd/pcmC0D0p", O_RDWR|O_NONBLOCK) = -1 EBUSY (Device or resource busy) but fuser and lsof show nothing. A trivial test program also sees Device or resource busy when trying to open /dev/snd/pcmC0D0p I am in favor of removing the <sound> tag from the default configuration, since I don't use sound from within guests and I do use sound on my desktop, but perhaps this behavior is specific to my configuration. I haven't investigated it exhaustively. What does everybody else think? Dave