[Xen-devel] [PATCH Altp2m cleanup 2/3 v12 2/3] Altp2m cleanup: cleaning up partial memory allocations in hap_enable().

[Paul Lai <paul.c.lai@xxxxxxxxx>]

In hap_enable(), clean up memory leaks upon failure of altp2m_domain_init().
Comment the memory error handling to help match allocs with cleanups.
Consolidate the memory error handing into single code path.
---
 xen/arch/x86/mm/hap/hap.c | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/xen/arch/x86/mm/hap/hap.c b/xen/arch/x86/mm/hap/hap.c
index 7fe6f83..e63ffb0 100644
--- a/xen/arch/x86/mm/hap/hap.c
+++ b/xen/arch/x86/mm/hap/hap.c
@@ -37,6 +37,7 @@
 #include <asm/hap.h>
 #include <asm/paging.h>
 #include <asm/p2m.h>
+#include <asm/altp2m.h>
 #include <asm/domain.h>
 #include <xen/numa.h>
 #include <asm/hvm/nestedhvm.h>
@@ -488,43 +489,44 @@ int hap_enable(struct domain *d, u32 mode)
     /* allocate P2m table */
     if ( mode & PG_translate )
     {
+        /* p2m_alloc_table() #1 */
         rv = p2m_alloc_table(p2m_get_hostp2m(d));
         if ( rv != 0 )
             goto out;
     }
 
     for (i = 0; i < MAX_NESTEDP2M; i++) {
+        /* nested p2m_alloc_table() #2 */
         rv = p2m_alloc_table(d->arch.nested_p2m[i]);
         if ( rv != 0 )
            goto out;
     }
 
-    if ( hvm_altp2m_supported() )
-    {
-        /* Init alternate p2m data */
-        if ( (d->arch.altp2m_eptp = alloc_xenheap_page()) == NULL )
-        {
-            rv = -ENOMEM;
-            goto out;
-        }
+    if ( (rv = altp2m_domain_init(d)) < 0 )
+        goto out;
 
-        for ( i = 0; i < MAX_EPTP; i++ )
-            d->arch.altp2m_eptp[i] = mfn_x(INVALID_MFN);
+    /* Now let other users see the new mode */
+    d->arch.paging.mode = mode | PG_HAP_enable;
 
-        for ( i = 0; i < MAX_ALTP2M; i++ )
-        {
-            rv = p2m_alloc_table(d->arch.altp2m_p2m[i]);
-            if ( rv != 0 )
-               goto out;
-        }
+    domain_unpause(d);
+    return rv;
 
-        d->arch.altp2m_active = 0;
+ out:
+    /* Unravel the partial nested p2m_alloc_table() #2 above */
+    for ( i = 0; i < MAX_NESTEDP2M; i++ )
+    {
+        p2m_teardown(d->arch.nested_p2m[i]);
     }
 
-    /* Now let other users see the new mode */
-    d->arch.paging.mode = mode | PG_HAP_enable;
+    /* Unravel p2m_alloc_table() #1 above */
+    p2m_teardown(p2m_get_hostp2m(d));
+
+    /* Unravel the hap_set_allocation(d, 256, NULL) above */
+    paging_lock(d);
+    hap_set_allocation(d, 0, NULL);
+    ASSERT(d->arch.paging.hap.p2m_pages == 0);
+    paging_unlock(d);
 
- out:
     domain_unpause(d);
     return rv;
 }
-- 
2.7.4


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