[Xen-changelog] [xen stable-4.3] x86: don't blindly create L3 tables for the direct map

[patchbot@xxxxxxx]

commit af727606a59af3d87e9126dea612110af3fbc711
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Oct 9 12:00:05 2013 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Oct 9 12:00:05 2013 +0200

    x86: don't blindly create L3 tables for the direct map
    
    Now that the direct map area can extend all the way up to almost the
    end of address space, this is wasteful.
    
    Also fold two almost redundant messages in SRAT parsing into one.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Tested-by: Malcolm Crossley <malcolm.crossley@xxxxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
    master commit: ca145fe70bad3a25ad54c6ded1ef237e45a2311e
    master date: 2013-09-30 15:28:12 +0200
---
 xen/arch/x86/mm.c        |    2 +-
 xen/arch/x86/srat.c      |   15 ++++++---------
 xen/arch/x86/x86_64/mm.c |   29 ++++++++++++-----------------
 xen/include/asm-x86/mm.h |    2 +-
 4 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index f151dec..1db363e 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -137,7 +137,7 @@ l1_pgentry_t __attribute__ ((__section__ 
(".bss.page_aligned")))
 #define PTE_UPDATE_WITH_CMPXCHG
 #endif
 
-bool_t __read_mostly mem_hotplug = 0;
+paddr_t __read_mostly mem_hotplug;
 
 /* Private domain structs for DOMID_XEN and DOMID_IO. */
 struct domain *dom_xen, *dom_io, *dom_cow;
diff --git a/xen/arch/x86/srat.c b/xen/arch/x86/srat.c
index ff73881..2b05272 100644
--- a/xen/arch/x86/srat.c
+++ b/xen/arch/x86/srat.c
@@ -113,6 +113,7 @@ static __init void bad_srat(void)
                apicid_to_node[i] = NUMA_NO_NODE;
        for (i = 0; i < ARRAY_SIZE(pxm2node); i++)
                pxm2node[i] = NUMA_NO_NODE;
+       mem_hotplug = 0;
 }
 
 /*
@@ -257,13 +258,6 @@ acpi_numa_memory_affinity_init(struct 
acpi_srat_mem_affinity *ma)
                return;
        }
        /* It is fine to add this area to the nodes data it will be used later*/
-       if (ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE)
-       {
-               printk(KERN_INFO "SRAT: hot plug zone found %"PRIx64" - 
%"PRIx64" \n",
-                               start, end);
-               mem_hotplug = 1;
-       }
-
        i = conflicting_memblks(start, end);
        if (i == node) {
                printk(KERN_WARNING
@@ -287,8 +281,11 @@ acpi_numa_memory_affinity_init(struct 
acpi_srat_mem_affinity *ma)
                if (nd->end < end)
                        nd->end = end;
        }
-       printk(KERN_INFO "SRAT: Node %u PXM %u %"PRIx64"-%"PRIx64"\n", node, 
pxm,
-              start, end);
+       if ((ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE) && end > mem_hotplug)
+               mem_hotplug = end;
+       printk(KERN_INFO "SRAT: Node %u PXM %u %"PRIx64"-%"PRIx64"%s\n",
+              node, pxm, start, end,
+              ma->flags & ACPI_SRAT_MEM_HOT_PLUGGABLE ? " (hotplug)" : "");
 
        node_memblk_range[num_node_memblks].start = start;
        node_memblk_range[num_node_memblks].end = end;
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 96a033b..d1a1c02 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -621,25 +621,20 @@ void __init paging_init(void)
      * We setup the L3s for 1:1 mapping if host support memory hotplug
      * to avoid sync the 1:1 mapping on page fault handler
      */
-    if ( mem_hotplug )
+    for ( va = DIRECTMAP_VIRT_START;
+          va < DIRECTMAP_VIRT_END && (void *)va < __va(mem_hotplug);
+          va += (1UL << L4_PAGETABLE_SHIFT) )
     {
-        unsigned long va;
-
-        for ( va = DIRECTMAP_VIRT_START;
-              va < DIRECTMAP_VIRT_END;
-              va += (1UL << L4_PAGETABLE_SHIFT) )
+        if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
+              _PAGE_PRESENT) )
         {
-            if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
-                  _PAGE_PRESENT) )
-            {
-                l3_pg = alloc_domheap_page(NULL, 0);
-                if ( !l3_pg )
-                    goto nomem;
-                l3_ro_mpt = page_to_virt(l3_pg);
-                clear_page(l3_ro_mpt);
-                l4e_write(&idle_pg_table[l4_table_offset(va)],
-                  l4e_from_page(l3_pg, __PAGE_HYPERVISOR));
-            }
+            l3_pg = alloc_domheap_page(NULL, 0);
+            if ( !l3_pg )
+                goto nomem;
+            l3_ro_mpt = page_to_virt(l3_pg);
+            clear_page(l3_ro_mpt);
+            l4e_write(&idle_pg_table[l4_table_offset(va)],
+                      l4e_from_page(l3_pg, __PAGE_HYPERVISOR));
         }
     }
 
diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h
index 213fc9c..5f03875 100644
--- a/xen/include/asm-x86/mm.h
+++ b/xen/include/asm-x86/mm.h
@@ -399,7 +399,7 @@ static inline int get_page_and_type(struct page_info *page,
 int check_descriptor(const struct domain *, struct desc_struct *d);
 
 extern bool_t opt_allow_superpage;
-extern bool_t mem_hotplug;
+extern paddr_t mem_hotplug;
 
 /******************************************************************************
  * With shadow pagetables, the different kinds of address start 
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.3

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