From: Wei Liu <wei.liu2@citrix.com>
Date: Mon, 24 Apr 2017 13:33:43 +0000 (+0100)
Subject: x86/domain: make release_compat_l4 NULL tolerant
X-Git-Tag: archive/raspbian/4.11.1-1+rpi1~1^2~66^2~2077
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=dfecffc84866c505aff2a16f521390a546a2b146;p=xen.git

x86/domain: make release_compat_l4 NULL tolerant

Push the check in caller down to that function so that it becomes
idempotent.

No functional change.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
---

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index f2847cf871..673a6d95f9 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -338,7 +338,8 @@ static int setup_compat_l4(struct vcpu *v)
 
 static void release_compat_l4(struct vcpu *v)
 {
-    free_domheap_page(pagetable_get_page(v->arch.guest_table));
+    if ( !pagetable_is_null(v->arch.guest_table) )
+        free_domheap_page(pagetable_get_page(v->arch.guest_table));
     v->arch.guest_table = pagetable_null();
     v->arch.guest_table_user = pagetable_null();
 }
@@ -379,9 +380,7 @@ int switch_compat(struct domain *d)
     for_each_vcpu( d, v )
     {
         free_compat_arg_xlat(v);
-
-        if ( !pagetable_is_null(v->arch.guest_table) )
-            release_compat_l4(v);
+        release_compat_l4(v);
     }
 
     return rc;