[v9,05/13] x86_64/mm: switch to new APIs in paging_init

Commit Message

Hongyan Xia April 6, 2021, 11:05 a.m. UTC

From: Wei Liu <[e-mail]>

Map and unmap pages instead of relying on the direct map.

Signed-off-by: Wei Liu <[e-mail]>
Signed-off-by: Hongyan Xia <[e-mail]>
Reviewed-by: Jan Beulich <[e-mail]>

---
Changed in v9:
- remove an unnecessary l3mfn variable.

Changed in v8:
- replace l3/2_ro_mpt_mfn with just mfn since their lifetimes do not
  overlap

Changed in v7:
- use the new alloc_map_clear_xen_pt() helper.
- move the unmap of pl3t up a bit.
- remove the unmaps in the nomem path.
---
 xen/arch/x86/x86_64/mm.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

Patch

diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index c5a47df01bde..da239f097703 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -498,6 +498,7 @@  void __init paging_init(void)
     l3_pgentry_t *l3_ro_mpt;
     l2_pgentry_t *pl2e = NULL, *l2_ro_mpt = NULL;
     struct page_info *l1_pg;
+    mfn_t mfn;
 
     /*
      * We setup the L3s for 1:1 mapping if host support memory hotplug
@@ -510,22 +511,22 @@  void __init paging_init(void)
         if ( !(l4e_get_flags(idle_pg_table[l4_table_offset(va)]) &
               _PAGE_PRESENT) )
         {
-            l3_pgentry_t *pl3t = alloc_xen_pagetable();
+            l3_pgentry_t *pl3t = alloc_map_clear_xen_pt(&mfn);
 
             if ( !pl3t )
                 goto nomem;
-            clear_page(pl3t);
+            UNMAP_DOMAIN_PAGE(pl3t);
             l4e_write(&idle_pg_table[l4_table_offset(va)],
-                      l4e_from_paddr(__pa(pl3t), __PAGE_HYPERVISOR_RW));
+                      l4e_from_mfn(mfn, __PAGE_HYPERVISOR_RW));
         }
     }
 
     /* Create user-accessible L2 directory to map the MPT for guests. */
-    if ( (l3_ro_mpt = alloc_xen_pagetable()) == NULL )
+    l3_ro_mpt = alloc_map_clear_xen_pt(&mfn);
+    if ( !l3_ro_mpt )
         goto nomem;
-    clear_page(l3_ro_mpt);
     l4e_write(&idle_pg_table[l4_table_offset(RO_MPT_VIRT_START)],
-              l4e_from_paddr(__pa(l3_ro_mpt), __PAGE_HYPERVISOR_RO | _PAGE_USER));
+              l4e_from_mfn(mfn, __PAGE_HYPERVISOR_RO | _PAGE_USER));
 
     /*
      * Allocate and map the machine-to-phys table.
@@ -608,12 +609,14 @@  void __init paging_init(void)
         }
         if ( !((unsigned long)pl2e & ~PAGE_MASK) )
         {
-            if ( (l2_ro_mpt = alloc_xen_pagetable()) == NULL )
+            UNMAP_DOMAIN_PAGE(l2_ro_mpt);
+
+            l2_ro_mpt = alloc_map_clear_xen_pt(&mfn);
+            if ( !l2_ro_mpt )
                 goto nomem;
-            clear_page(l2_ro_mpt);
+
             l3e_write(&l3_ro_mpt[l3_table_offset(va)],
-                      l3e_from_paddr(__pa(l2_ro_mpt),
-                                     __PAGE_HYPERVISOR_RO | _PAGE_USER));
+                      l3e_from_mfn(mfn, __PAGE_HYPERVISOR_RO | _PAGE_USER));
             pl2e = l2_ro_mpt;
             ASSERT(!l2_table_offset(va));
         }
@@ -625,15 +628,18 @@  void __init paging_init(void)
     }
 #undef CNT
 #undef MFN
+    UNMAP_DOMAIN_PAGE(l2_ro_mpt);
+    UNMAP_DOMAIN_PAGE(l3_ro_mpt);
 
     /* Create user-accessible L2 directory to map the MPT for compat guests. */
     if ( opt_pv32 )
     {
-        if ( (l2_ro_mpt = alloc_xen_pagetable()) == NULL )
+        mfn = alloc_xen_pagetable_new();
+        if ( mfn_eq(mfn, INVALID_MFN) )
             goto nomem;
-        compat_idle_pg_table_l2 = l2_ro_mpt;
-        clear_page(l2_ro_mpt);
-        pl2e = l2_ro_mpt;
+        compat_idle_pg_table_l2 = map_domain_page_global(mfn);
+        clear_page(compat_idle_pg_table_l2);
+        pl2e = compat_idle_pg_table_l2;
 
         /* Allocate and map the compatibility mode machine-to-phys table. */
         mpt_size = (mpt_size >> 1) + (1UL << (L2_PAGETABLE_SHIFT - 1));