Transfer files between host and guest using virtio-serial

I have a Windows 10 guest with very limited network access (limited by Check-Point VPN firewall) which I access through the spice viewer.
But I need to transfer files to/from the guest.
I tried to setup Folder Sharing (a function of the virt remote spice viewer) but even that seemed to be blocked by the guest firewall (cannot access the webdavd service).
I assume my only option is to use the virtio-serial as this will not use network.
My first problem is to define a channel in the virt XML file:

<channel type='unix'> <source type='bind' path='/tmp/foo'/> <target type='virtio' port='0'/>
</channel>

But I get the error

error: XML document failed to validate against schema: Unable to validate doc against /usr/share/libvirt/schemas/domain.rng
Extra element devices in interleave
Element domain failed to validate content

Any help are appreciated.

1 Answer

A new solution is under development: virtio-fs. Not using network but FUSE.

Still not sure if it's usable in Windows guests.

PDF: Virtio-fs for Kata Containers storage