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[xen master] x86: correct boot time page table setup

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[xen master] x86: correct boot time page table setup

patchbot
commit a0a9095432f6f8b7c83e779dad5debc81c552583
Author:     Jan Beulich <[hidden email]>
AuthorDate: Mon May 8 14:56:14 2017 +0200
Commit:     Jan Beulich <[hidden email]>
CommitDate: Mon May 8 14:56:14 2017 +0200

    x86: correct boot time page table setup
   
    While using alloc_domheap_pages() and assuming the allocated memory is
    directly accessible is okay at boot time (as we run on the idle page
    tables there), memory hotplug code too assumes it can access the
    resulting page tables without using map_domain_page() or alike, and
    hence we need to obtain memory suitable for ordinary page table use
    here.
   
    Signed-off-by: Jan Beulich <[hidden email]>
    Reviewed-by: Andrew Cooper <[hidden email]>
    Release-acked-by: Julien Grall <[hidden email]>
---
 xen/arch/x86/x86_64/mm.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index ac358a8..aa1b94f 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -496,7 +496,7 @@ void __init paging_init(void)
     unsigned int n, memflags;
     l3_pgentry_t *l3_ro_mpt;
     l2_pgentry_t *l2_ro_mpt = NULL;
-    struct page_info *l1_pg, *l2_pg, *l3_pg;
+    struct page_info *l1_pg;
 
     /*
      * We setup the L3s for 1:1 mapping if host support memory hotplug
@@ -509,23 +509,22 @@ void __init paging_init(void)
         if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
               _PAGE_PRESENT) )
         {
-            l3_pg = alloc_domheap_page(NULL, 0);
-            if ( !l3_pg )
+            l3_pgentry_t *pl3t = alloc_xen_pagetable();
+
+            if ( !pl3t )
                 goto nomem;
-            l3_ro_mpt = page_to_virt(l3_pg);
-            clear_page(l3_ro_mpt);
+            clear_page(pl3t);
             l4e_write(&idle_pg_table[l4_table_offset(va)],
-                      l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RW));
+                      l4e_from_paddr(__pa(pl3t), __PAGE_HYPERVISOR_RW));
         }
     }
 
     /* Create user-accessible L2 directory to map the MPT for guests. */
-    if ( (l3_pg = alloc_domheap_page(NULL, 0)) == NULL )
+    if ( (l3_ro_mpt = alloc_xen_pagetable()) == NULL )
         goto nomem;
-    l3_ro_mpt = page_to_virt(l3_pg);
     clear_page(l3_ro_mpt);
     l4e_write(&idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)],
-              l4e_from_page(l3_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+              l4e_from_paddr(__pa(l3_ro_mpt), __PAGE_HYPERVISOR_RO | _PAGE_USER));
 
     /*
      * Allocate and map the machine-to-phys table.
@@ -607,12 +606,12 @@ void __init paging_init(void)
         }
         if ( !((unsigned long)l2_ro_mpt & ~PAGE_MASK) )
         {
-            if ( (l2_pg = alloc_domheap_page(NULL, memflags)) == NULL )
+            if ( (l2_ro_mpt = alloc_xen_pagetable()) == NULL )
                 goto nomem;
-            l2_ro_mpt = page_to_virt(l2_pg);
             clear_page(l2_ro_mpt);
             l3e_write(&l3_ro_mpt[l3_table_offset(va)],
-                      l3e_from_page(l2_pg, __PAGE_HYPERVISOR_RO | _PAGE_USER));
+                      l3e_from_paddr(__pa(l2_ro_mpt),
+                                     __PAGE_HYPERVISOR_RO | _PAGE_USER));
             ASSERT(!l2_table_offset(va));
         }
         /* NB. Cannot be GLOBAL: guest user mode should not see it. */
--
generated by git-patchbot for /home/xen/git/xen.git#master

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