libxc: after saving, unmap correct amount for live_m2p

libxc: after saving, unmap correct amount for live_m2p

With some help from Olaf, I've finally got to the bottom of an issue I
came across while trying to implement save/restore in the libvirt
libxenlight driver.  After issuing the save operation, the saved
domain was not being cleaned up properly and left in this state from
xl's perspective

xen33:# xl list
Name                   ID   Mem VCPUs      State   Time(s)
Domain-0                0  6821     8     r-----     122.5
(null)                  2     2     2     --pssd      10.8

Checking the libvirtd /proc/$pid/maps I found this

7f3798984000-7f3798b86000 r--s 00002000 00:03 4026532097
/proc/xen/privcmd

So not all all pages belonging to the domain were unmapped from
libvirtd.  In tools/libxc/xc_domain_save.c we found that
P2M_FL_ENTRIES were being mapped but only P2M_FLL_ENTRIES were being
unmapped.  The attached patch changes the unmapping to use the same
P2M_FL_ENTRIES macro.  I'm not too familiar with this code though so
posting here for review.

I suspect this was not noticed before since most (all?) processes
doing save terminate after the save and are not long-running like
libvirtd.

Ian Campbell writes:
> Looks like I introduced this in 18558:ccf0205255e1, sorry!
>
> I guess it is also wrong in the error path out of map_and_save_p2m_table
> and so we also need [another hunk].

This change should be backported to relevant earlier trees. -iwj

From: Jim Fehlig <jfehlig@novell.com>
From: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Olaf Hering <olaf@aepfle.de>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>
xen-unstable changeset:   23373:171007b4e2c4
xen-unstable date:        Tue May 24 14:50:00 2011 +0100