The xl toolstack is the modern command-line management interface used for administering the Xen hypervisor, replacing the older xm toolstack. According to official Xen virtualization documentation, the global configuration file for the xl toolstack is /etc/xen/xl.conf.

This configuration file defines default behaviors and policies for the xl management commands. It allows administrators to configure global settings such as default CPU scheduling behavior, memory handling, device model settings, and other operational parameters that affect how virtual machines (domains) are managed on a Xen host. These settings apply system-wide and influence the behavior of all xl commands unless overridden by per-domain configuration files.

The file /etc/xen/xl.conf is read by the xl toolstack at runtime and is part of the standard Xen configuration directory structure. Individual virtual machine definitions are typically stored as separate configuration files in /etc/xen/, but xl.conf serves as the central, global configuration reference.

Virtualization notes emphasize that proper configuration of xl.conf is important for performance tuning, stability, and compliance in Xen-based environments. While many default installations function correctly without modifying this file, enterprise deployments often customize it to align with workload requirements and hardware capabilities.

Therefore, the correct and documented global configuration file for the xl toolstack is /etc/xen/xl.conf.