x86: make show_page_walk() more robust

Also add in a missing line in x86-64's do_page_walk().

Signed-off-by: Jan Beulich <jbeulich@novell.com>

diff --git a/xen/arch/x86/x86_32/traps.c b/xen/arch/x86/x86_32/traps.c
index c58e5e29180f86c3a0b33974e12569cbf5064871..68682d25453ed29a208c024e03bbc33fb4b3d847 100644 (file)
--- a/xen/arch/x86/x86_32/traps.c
+++ b/xen/arch/x86/x86_32/traps.c
@@ -164,7 +164,8 @@ void show_page_walk(unsigned long addr)
     printk(" L3[0x%03lx] = %"PRIpte" %08lx\n",
            l3_table_offset(addr), l3e_get_intpte(l3e), pfn);
     unmap_domain_page(l3t);
-    if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) )
+    if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) ||
+         !mfn_valid(mfn) )
         return;
 
     l2t = map_domain_page(mfn);
@@ -176,7 +177,8 @@ void show_page_walk(unsigned long addr)
            (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : "");
     unmap_domain_page(l2t);
     if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) ||
-         (l2e_get_flags(l2e) & _PAGE_PSE) )
+         (l2e_get_flags(l2e) & _PAGE_PSE) ||
+         !mfn_valid(mfn) )
         return;
 
     l1t = map_domain_page(mfn);

diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 87b8957ff5440e43959d9b8587b24c4dbc5854e8..352fa439c57664a49f897e9bfa5bede2aaf9e9d5 100644 (file)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -123,6 +123,7 @@ void *do_page_walk(struct vcpu *v, unsigned long addr)
     l3e = l3t[l3_table_offset(addr)];
     mfn = l3e_get_pfn(l3e);
     if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) || !mfn_valid(mfn) )
+        return NULL;
     if ( (l3e_get_flags(l3e) & _PAGE_PSE) )
         return mfn_to_virt(mfn) + (addr & ((1UL << L3_PAGETABLE_SHIFT) - 1));
 

diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index f458f491c7df2fe73f0dd285f43dbef5d9037911..4c74785c74a9302fd563ff990a27f0c22f73148a 100644 (file)
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -179,7 +179,8 @@ void show_page_walk(unsigned long addr)
     pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L4[0x%03lx] = %"PRIpte" %016lx\n",
            l4_table_offset(addr), l4e_get_intpte(l4e), pfn);
-    if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) )
+    if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) ||
+         !mfn_valid(mfn) )
         return;
 
     l3t = mfn_to_virt(mfn);
@@ -190,7 +191,8 @@ void show_page_walk(unsigned long addr)
            l3_table_offset(addr), l3e_get_intpte(l3e), pfn,
            (l3e_get_flags(l3e) & _PAGE_PSE) ? " (PSE)" : "");
     if ( !(l3e_get_flags(l3e) & _PAGE_PRESENT) ||
-         (l3e_get_flags(l3e) & _PAGE_PSE) )
+         (l3e_get_flags(l3e) & _PAGE_PSE) ||
+         !mfn_valid(mfn) )
         return;
 
     l2t = mfn_to_virt(mfn);
@@ -201,7 +203,8 @@ void show_page_walk(unsigned long addr)
            l2_table_offset(addr), l2e_get_intpte(l2e), pfn,
            (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : "");
     if ( !(l2e_get_flags(l2e) & _PAGE_PRESENT) ||
-         (l2e_get_flags(l2e) & _PAGE_PSE) )
+         (l2e_get_flags(l2e) & _PAGE_PSE) ||
+         !mfn_valid(mfn) )
         return;
 
     l1t = mfn_to_virt(mfn);