[Xen-changelog] [xen-4.1-testing] p2m: query/modify p2mt with p2m_lock held

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1331107198 0
# Node ID 637eaa1421d1ae9808f1cc56c39b2d9e1fe64eb9
# Parent  7ee4016eeb9fb1c05f033e2b9da78cf5564c3e54
p2m: query/modify p2mt with p2m_lock held

Query and update the p2mt in set_mmio_p2m_entry, clear_mmio_p2m_entry
and set_shared_p2m_entry with the p2m_lock held.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
Committed-by: Tim Deegan <tim@xxxxxxx>
xen-unstable changeset:   23908:88b6e08b8aa8
xen-unstable date:        Thu Oct 06 14:15:43 2011 +0100
---


diff -r 7ee4016eeb9f -r 637eaa1421d1 xen/arch/x86/mm/p2m.c
--- a/xen/arch/x86/mm/p2m.c     Wed Mar 07 07:55:10 2012 +0000
+++ b/xen/arch/x86/mm/p2m.c     Wed Mar 07 07:59:58 2012 +0000
@@ -2752,9 +2752,11 @@
     if ( !paging_mode_translate(p2m->domain) )
         return 0;
 
+    p2m_lock(p2m);
     omfn = gfn_to_mfn_query(p2m, gfn, &ot);
     if ( p2m_is_grant(ot) )
     {
+        p2m_unlock(p2m);
         domain_crash(p2m->domain);
         return 0;
     }
@@ -2765,7 +2767,6 @@
     }
 
     P2M_DEBUG("set mmio %lx %lx\n", gfn, mfn_x(mfn));
-    p2m_lock(p2m);
     rc = set_p2m_entry(p2m, gfn, mfn, 0, p2m_mmio_direct, p2m->default_access);
     audit_p2m(p2m, 1);
     p2m_unlock(p2m);
@@ -2786,18 +2787,20 @@
     if ( !paging_mode_translate(p2m->domain) )
         return 0;
 
-    mfn = gfn_to_mfn(p2m, gfn, &t);
+    p2m_lock(p2m);
+    mfn = gfn_to_mfn_query(p2m, gfn, &t);
 
     /* Do not use mfn_valid() here as it will usually fail for MMIO pages. */
     if ( (INVALID_MFN == mfn_x(mfn)) || (t != p2m_mmio_direct) )
     {
         gdprintk(XENLOG_ERR,
             "clear_mmio_p2m_entry: gfn_to_mfn failed! gfn=%08lx\n", gfn);
-        return 0;
+        goto out;
     }
-    p2m_lock(p2m);
     rc = set_p2m_entry(p2m, gfn, _mfn(INVALID_MFN), 0, p2m_invalid, 
p2m->default_access);
     audit_p2m(p2m, 1);
+
+out:
     p2m_unlock(p2m);
 
     return rc;
@@ -2814,6 +2817,8 @@
     if ( !paging_mode_translate(p2m->domain) )
         return 0;
 
+    if ( need_lock ) 
+        p2m_lock(p2m);
     omfn = gfn_to_mfn_query(p2m, gfn, &ot);
     /* At the moment we only allow p2m change if gfn has already been made
      * sharable first */
@@ -2823,8 +2828,6 @@
     set_gpfn_from_mfn(mfn_x(omfn), INVALID_M2P_ENTRY);
 
     P2M_DEBUG("set shared %lx %lx\n", gfn, mfn_x(mfn));
-    if ( need_lock ) 
-        p2m_lock(p2m);
     rc = set_p2m_entry(p2m, gfn, mfn, 0, p2m_ram_shared, p2m->default_access);
     if ( need_lock ) 
         p2m_unlock(p2m);

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