[Xen-devel] [PATCH] Backport fixes to PoD codepaths related to 1GiB pages

[George Dunlap <george.dunlap@xxxxxxxxxxxxx>]

Backport of xen-unstable.hg c/s 24189:7da681c490e0 to xen-4.1-testing

The codepaths in p2m_gfn_to_mfn() and p2m_gfn_to_mfn_current() should
call p2m_pod_check_and_popualte(), as the 2MiB and 4k codepaths do.
This properly grabs the p2m lock.

Also, p2m_pod_demand_populate() shouldn't call p2m_unlock(), as it
didn't grab the lock in the first place.

Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

diff -r c613d436ca09 -r 3ab01c6cd13f xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c     Tue Nov 22 19:03:04 2011 +0000
+++ b/xen/arch/x86/mm/p2m.c     Thu Dec 01 12:56:18 2011 +0000
@@ -1244,7 +1244,6 @@ p2m_pod_demand_populate(struct p2m_domai
         set_p2m_entry(p2m, gfn_aligned, _mfn(POPULATE_ON_DEMAND_MFN), 9,
                       p2m_populate_on_demand, p2m->default_access);
         audit_p2m(p2m, 1);
-        p2m_unlock(p2m);
         return 0;
     }
 
@@ -1602,7 +1601,8 @@ pod_retry_l3:
             {
                 if ( q != p2m_query )
                 {
-                    if ( !p2m_pod_demand_populate(p2m, gfn, 18, q) )
+                    if ( !p2m_pod_check_and_populate(p2m, gfn,
+                              (l1_pgentry_t *) &l3e, 18, q) )
                         goto pod_retry_l3;
                 }
                 else
@@ -1733,7 +1733,8 @@ static mfn_t p2m_gfn_to_mfn_current(stru
                 /* The read has succeeded, so we know that mapping exists */
                 if ( q != p2m_query )
                 {
-                    if ( !p2m_pod_demand_populate(p2m, gfn, 18, q) )
+                    if ( !p2m_pod_check_and_populate(p2m, gfn,
+                              (l1_pgentry_t *) &l3e, 18, q) )
                         goto pod_retry_l3;
                     p2mt = p2m_invalid;
                     printk("%s: Allocate 1GB failed!\n", __func__);

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