core-admin/dom0/system-config/udev-qubes-block.rules

# Expose all (except xen-frontend) block devices via xenstore

# Only block devices are interesting
SUBSYSTEM!="block", GOTO="qubes_block_end"

# Skip xen-blkfront devices
ENV{MAJOR}=="202", GOTO="qubes_block_end"

# Skip device-mapper devices
ENV{MAJOR}=="253", GOTO="qubes_block_end"

IMPORT{db}="QUBES_EXPOSED"
ACTION=="add", IMPORT{program}="/usr/lib/qubes/udev-block-add-change"
ACTION=="change", IMPORT{program}="/usr/lib/qubes/udev-block-add-change"
ACTION=="remove", RUN+="/usr/lib/qubes/udev-block-remove"

LABEL="qubes_block_end"

# Cleanup disconnected frontend from xenstore
ACTION=="remove", SUBSYSTEM=="block", ENV{MAJOR}=="202", RUN+="/usr/lib/qubes/udev-block-cleanup"