Xen is a hypervisor which supports running multiple guest operating
systems on a single machine. Guest OSes (also called "domains")
can be either paravirtualised (i.e. make hypercalls in order to
access hardware), run in HVM (Hardware Virtualisation Mode) where
they will be presented with virtual devices, or a combination where
they use hypercalls to access hardware but manage memory themselves.
At boot, the xen kernel is loaded along with the guest kernel for
the first domain (called domain0). domain0 has privileges to access
the physical hardware (PCI and ISA devices), administrate other
domains and provide virtual devices (disks and network) to other
domains.

This package contains the 4.18 Xen kernel itself.  PCI passthrough is
not supported.  PAE is mandatory; on i386 one must use XEN3PAE_DOMU.

Note that unlike upstream Xen, pv-linear-pt defaults to true.
You can disable it using pv-linear-pt=false on the Xen command line,
but then you can't boot NetBSD in PV mode.

32bits PV guests are not officially supported any more.
Switch to pvshim (for netbsd-9 or older) or pvh (for netbsd-10 or newer).

Unline upstream, SHADOW_PAGING is enabled by default as NetBSD PV guests
relies on it. Note that this is not security-supported upstream any more.
