[libvirt] staggered guest startup / startup order

Richard W.M. Jones rjones at redhat.com
Tue May 26 16:39:44 UTC 2009

In addition to Dan's reply, operating systems ought to indicate what
stage they have reached in the boot process (eg.  "BIOS up", "kernel
up", "userspace up", "applications started"), perhaps by writing a
status code into a register.

Some PC BIOSes do this already, writing to IO port 0x80, see for


If you are using a watchdog driver, feasibly you might use this to
detect when userspace in the guest is active.

Anyway, this is worth discussing with the relevant upstream projects,
QEMU, IPMI, various watchdog hardware ...


Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
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