fix zombie domain when destroying 2.6 linux vmx guest

PATCH New Ling, Xiaofeng 1 participant 1 message Nov 22, 2005

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Ling, Xiaofeng

author

2005-11-22 02:10 UTC #0 lore raw

PATCH 1/1 fix zombie domain when destroying 2.6 linux vmx guest

Fix the zombie domain when destroying 2.6 linux vmx guest. The zombie domain is caused by unreleased shadow page because of lack of put_shadow_ref.
When unshadow a L1 page, set l2e to zero and put ref.

Signed-off-by <[email protected]>

# HG changeset patch
# User Xiaofeng Ling <[email protected]> # Node ID dd78c7cb5cf29510b8651ea9394c9385e291b888 # Parent 27a2cb379c8ffcca77d9ec262d3baf06e7f85175 Fix the zombie domain when destroy 2.6 linux vmx guest. The zombie domain is caused by unreleased shadow page because of lack of put_shadow_ref.
When unshadow a L1 page, set l2e to zero and put ref.

Signed-off-by <[email protected]>

xen/arch/x86/shadow.c +3 -2

diff -r 27a2cb379c8f -r dd78c7cb5cf2 xen/arch/x86/shadow.c
@@ -1536,12 +1536,13 @@
             perfc_incr_histo(l1_entries_checked, max_shadow - min_shadow + 1, PT_UPDATES);
             if ( d->arch.ops->guest_paging_levels >= PAGING_L3 &&
                  unshadow_l1 ) {
-                pgentry_64_t l2e = {0};
+                pgentry_64_t l2e;
 
                 __shadow_get_l2e(entry->v, entry->va, &l2e);
 
                 if ( entry_get_flags(l2e) & _PAGE_PRESENT ) {
-                    entry_remove_flags(l2e, _PAGE_PRESENT);
+                    put_shadow_ref(entry_get_pfn(l2e));
+                    l2e = entry_empty();
                     __shadow_set_l2e(entry->v, entry->va, &l2e);
 
                     if (entry->v == current)

xen/arch/x86/shadow32.c +2 -1

diff -r 27a2cb379c8f -r dd78c7cb5cf2 xen/arch/x86/shadow32.c
@@ -2426,7 +2426,8 @@
 
                 __shadow_get_l2e(entry->v, entry->va, &l2e);
                 if (l2e_get_flags(l2e) & _PAGE_PRESENT) {
-                    l2e_remove_flags(l2e, _PAGE_PRESENT);
+                    put_shadow_ref(l2e_get_pfn(l2e)); 
+                    l2e = l2e_empty();
                     __shadow_set_l2e(entry->v, entry->va, l2e);
 
                     if (entry->v == current)

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