• Jeremy Fitzhardinge's avatar
    xen: implement save/restore · 0e91398f
    Jeremy Fitzhardinge authored
    This patch implements Xen save/restore and migration.
    
    Saving is triggered via xenbus, which is polled in
    drivers/xen/manage.c.  When a suspend request comes in, the kernel
    prepares itself for saving by:
    
    1 - Freeze all processes.  This is primarily to prevent any
        partially-completed pagetable updates from confusing the suspend
        process.  If CONFIG_PREEMPT isn't defined, then this isn't necessary.
    
    2 - Suspend xenbus and other devices
    
    3 - Stop_machine, to make sure all the other vcpus are quiescent.  The
        Xen tools require the domain to run its save off vcpu0.
    
    4 - Within the stop_machine state, it pins any unpinned pgds (under
        construction or destruction), performs canonicalizes various other
        pieces of state (mostly converting mfns to pfns), and finally
    
    5 - Suspend the domain
    
    Restore reverses the steps used to save the domain, ending when all
    the frozen processes are thawed.
    Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    0e91398f
events.h 1.38 KB