The KVM changes were merged yesterday for Linux 6.13 in further enhancing the open-source virtualization stack. Kernel-based Virtual Machine maintainer Paolo Bonzini of Red Hat explained of the biggest change for the KVM feature code in Linux 6.13: "The biggest change here is eliminating the awful idea that KVM had, of essentially guessing which pfns are refcounted pages. The reason to do so was that KVM needs to map both non-refcounted pages (for example BARs of VFIO devices) and VM_PFNMAP/VM_...