[Xen-changelog] [xen master] x86/mm: make free_perdomain_mappings() idempotent

[patchbot@xxxxxxx]

commit ebcba577682691dd82b82e46489316e3ca8ecdf3
Author:     Wei Liu <wei.liu2@xxxxxxxxxx>
AuthorDate: Tue Apr 25 13:00:17 2017 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue May 30 18:50:13 2017 +0100

    x86/mm: make free_perdomain_mappings() idempotent
    
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
---
 xen/arch/x86/mm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index 77b0af1..411eed0 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -6514,9 +6514,14 @@ void destroy_perdomain_mapping(struct domain *d, 
unsigned long va,
 
 void free_perdomain_mappings(struct domain *d)
 {
-    l3_pgentry_t *l3tab = __map_domain_page(d->arch.perdomain_l3_pg);
+    l3_pgentry_t *l3tab;
     unsigned int i;
 
+    if ( !d->arch.perdomain_l3_pg )
+        return;
+
+    l3tab = __map_domain_page(d->arch.perdomain_l3_pg);
+
     for ( i = 0; i < PERDOMAIN_SLOTS; ++i)
         if ( l3e_get_flags(l3tab[i]) & _PAGE_PRESENT )
         {
@@ -6555,6 +6560,7 @@ void free_perdomain_mappings(struct domain *d)
 
     unmap_domain_page(l3tab);
     free_domheap_page(d->arch.perdomain_l3_pg);
+    d->arch.perdomain_l3_pg = NULL;
 }
 
 #ifdef MEMORY_GUARD
--
generated by git-patchbot for /home/xen/git/xen.git#master

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