arm/p2m: Fix regression during domain shutdown with active mem_access

The change in commit 438c5fe4f0c introduced a regression for domains where
mem_acces is or was active. When relinquish_p2m_mapping attempts to clear
a page where the order is not 0 the following ASSERT is triggered:

    ASSERT(!p2m->mem_access_enabled || page_order == 0);

This regression was unfortunately not caught during testing in preparation
for the 4.8 release.

In this patch we adjust the ASSERT to not trip when the domain
is being shutdown.

Ideally this fix would be part of Xen 4.8.1.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Acked-by: Julien Grall <julien.grall@arm.com>

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index 09ceb378a54cd1e33dc1b0a08b2c4e02731fd74c..7762f453f531d705fa84fae5f0430ccdac05cf37 100644 (file)
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -991,9 +991,10 @@ static int __p2m_set_entry(struct p2m_domain *p2m,
 
     /*
      * The radix-tree can only work on 4KB. This is only used when
-     * memaccess is enabled.
+     * memaccess is enabled and during shutdown.
      */
-    ASSERT(!p2m->mem_access_enabled || page_order == 0);
+    ASSERT(!p2m->mem_access_enabled || page_order == 0 ||
+           p2m->domain->is_dying);
     /*
      * The access type should always be p2m_access_rwx when the mapping
      * is removed.