[Xen-devel] [PATCH 09 of 17] x86/mm/p2m: Fix locking discipline around p2m updates

[Tim Deegan <Tim.Deegan@xxxxxxxxxx>]

# HG changeset patch
# User Tim Deegan <Tim.Deegan@xxxxxxxxxx>
# Date 1307017012 -3600
# Node ID 32f80f08d7246cac9c75d4820698e754550a425a
# Parent  dd89c48f2ac5c55e8a46159390c2c2f83a7b7742
x86/mm/p2m: Fix locking discipline around p2m updates.

Direct callers of the p2m setting functions must hold the p2m lock.

Signed-off-by: Tim Deegan <Tim.Deegan@xxxxxxxxxx>

diff -r dd89c48f2ac5 -r 32f80f08d724 xen/arch/x86/mm/hap/nested_hap.c
--- a/xen/arch/x86/mm/hap/nested_hap.c  Thu Jun 02 13:16:52 2011 +0100
+++ b/xen/arch/x86/mm/hap/nested_hap.c  Thu Jun 02 13:16:52 2011 +0100
@@ -103,9 +103,12 @@ nestedhap_fix_p2m(struct p2m_domain *p2m
     ASSERT(p2m);
     ASSERT(p2m->set_entry);
 
-    rv = p2m->set_entry(p2m, L2_gpa >> PAGE_SHIFT,
+    p2m_lock(p2m);
+    rv = set_p2m_entry(p2m, L2_gpa >> PAGE_SHIFT,
                          page_to_mfn(maddr_to_page(L0_gpa)),
                          0 /*4K*/, p2mt, p2ma);
+    p2m_unlock(p2m);
+
     if (rv == 0) {
         gdprintk(XENLOG_ERR,
                "failed to set entry for 0x%"PRIx64" -> 0x%"PRIx64"\n",
diff -r dd89c48f2ac5 -r 32f80f08d724 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c     Thu Jun 02 13:16:52 2011 +0100
+++ b/xen/arch/x86/mm/p2m.c     Thu Jun 02 13:16:52 2011 +0100
@@ -140,6 +140,8 @@ int set_p2m_entry(struct p2m_domain *p2m
     unsigned int order;
     int rc = 1;
 
+    ASSERT(p2m_locked_by_me(p2m));
+
     while ( todo )
     {
         if ( hap_enabled(d) )

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