[Xen-devel] [PATCH 5 of 6] x86/mm/shadow: fix p2m/paging deadlock when updating shadow cr3

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

 xen/arch/x86/mm/shadow/multi.c |  13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)


Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r a7ca6ae73992 -r 1d8566a05642 xen/arch/x86/mm/shadow/multi.c
--- a/xen/arch/x86/mm/shadow/multi.c
+++ b/xen/arch/x86/mm/shadow/multi.c
@@ -4190,7 +4190,12 @@ sh_update_cr3(struct vcpu *v, int do_loc
         return;
     }
 
-    if ( do_locking ) paging_lock(v->domain);
+    if ( do_locking ) 
+    {
+        /* See comment in shadow_update_paging_modes. */
+        p2m_lock(p2m_get_hostp2m(v->domain));
+        paging_lock(v->domain);
+    }
 
 #if (SHADOW_OPTIMIZATIONS & SHOPT_OUT_OF_SYNC)
     /* Need to resync all the shadow entries on a TLB flush.  Resync
@@ -4434,7 +4439,11 @@ sh_update_cr3(struct vcpu *v, int do_loc
 #endif
 
     /* Release the lock, if we took it (otherwise it's the caller's problem) */
-    if ( do_locking ) paging_unlock(v->domain);
+    if ( do_locking )
+    {
+        paging_unlock(v->domain);
+        p2m_unlock(p2m_get_hostp2m(v->domain));
+    }
 }
 
 

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