Problems starting Xen DomUs with linux 5.10.11 as Dom0 kernel
This is a known problem, also discussed in #alpine-devel@freenode, mentioned here for others to see.
If you find yourself having this problem
libxl: error: libxl_device.c:1103:device_backend_callback: Domain 1:unable to add device with path /local/domain/0/backend/vbd/3/2048
libxl: error: libxl_device.c:1103:device_backend_callback: Domain 1:unable to add device with path /local/domain/0/backend/vbd/3/2064
libxl: error: libxl_create.c:1608:domcreate_launch_dm: Domain 1:unable to add disk devices
libxl: error: libxl_device.c:1103:device_backend_callback: Domain 1:unable to remove device with path /local/domain/0/backend/vbd/3/2048
libxl: error: libxl_device.c:1103:device_backend_callback: Domain 1:unable to remove device with path /local/domain/0/backend/vbd/3/2064
libxl: error: libxl_domain.c:1529:devices_destroy_cb: Domain 1:libxl__devices_destroy failed
libxl: error: libxl_domain.c:1182:libxl__destroy_domid: Domain 1:Non-existant domain
libxl: error: libxl_domain.c:1136:domain_destroy_callback: Domain 1:Unable to destroy guest
libxl: error: libxl_domain.c:1063:domain_destroy_cb: Domain 1:Destruction of domain failed
the workaround is to downgrade your Dom0 kernel from linux 5.10.11-r0 to 5.10.10-r0, until the patch is backported or linux 5.10.12 is released.