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xen: implement save/restore

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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: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jeremy Fitzhardinge
2008-05-26 23:31:27 +01:00
committed by Thomas Gleixner
parent 7d88d32a46
commit 0e91398f2a
14 changed files with 317 additions and 20 deletions
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4
drivers/xen/grant-table.c
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@@ -471,14 +471,14 @@ static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
return 0;
}
static int gnttab_resume(void)
int gnttab_resume(void)
{
if (max_nr_grant_frames() < nr_grant_frames)
return -ENOSYS;
return gnttab_map(0, nr_grant_frames - 1);
}
static int gnttab_suspend(void)
int gnttab_suspend(void)
{
arch_gnttab_unmap_shared(shared, nr_grant_frames);
return 0;