x86: drop high compat r/o M2P table address range

Now that we don't properly hook things up into the page tables anymore
we also don't need to set aside an address range. Drop it, using
compat_idle_pg_table_l2[] simply (explicitly) from slot 0.

While doing the re-arrangement, which is accompanied by the dropping or
replacing of some local variables, restrict the scopes of some further
ones at the same time.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Wei Liu <wl@xen.org>

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index ab9cd00225dc9e85bd7cdda8420243016e3bd41f..355c50ff919dd3fcedea0c15d533c6fba95c4107 100644 (file)
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -1423,8 +1423,7 @@ static bool pae_xen_mappings_check(const struct domain *d,
 void init_xen_pae_l2_slots(l2_pgentry_t *l2t, const struct domain *d)
 {
     memcpy(&l2t[COMPAT_L2_PAGETABLE_FIRST_XEN_SLOT(d)],
-           &compat_idle_pg_table_l2[
-               l2_table_offset(HIRO_COMPAT_MPT_VIRT_START)],
+           compat_idle_pg_table_l2,
            COMPAT_L2_PAGETABLE_XEN_SLOTS(d) * sizeof(*l2t));
 }
 

diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 39c01cf907d0a6b46ccd423f326b65fe94648e6b..102079a801b9e9417acb1966d9f2edb5884fb5ca 100644 (file)
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -216,9 +216,7 @@ static int share_hotadd_m2p_table(struct mem_hotadd_info *info)
 
 static void destroy_compat_m2p_mapping(struct mem_hotadd_info *info)
 {
-    unsigned long i, va, rwva, pt_pfn;
-    unsigned long smap = info->spfn, emap = info->spfn;
-    l2_pgentry_t *l2_ro_mpt = compat_idle_pg_table_l2;
+    unsigned long i, smap = info->spfn, emap = info->spfn;
 
     if ( smap > ((RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START) >> 2) )
         return;
@@ -228,18 +226,19 @@ static void destroy_compat_m2p_mapping(struct mem_hotadd_info *info)
 
     for ( i = smap; i < emap; )
     {
-        va = HIRO_COMPAT_MPT_VIRT_START +
-              i * sizeof(*compat_machine_to_phys_mapping);
-        rwva = RDWR_COMPAT_MPT_VIRT_START +
-             i * sizeof(*compat_machine_to_phys_mapping);
-        if ( l2e_get_flags(l2_ro_mpt[l2_table_offset(va)]) & _PAGE_PRESENT )
+        unsigned int off = i * sizeof(*compat_machine_to_phys_mapping);
+        l2_pgentry_t *pl2e = compat_idle_pg_table_l2 + l2_table_offset(off);
+
+        if ( l2e_get_flags(*pl2e) & _PAGE_PRESENT )
         {
-            pt_pfn = l2e_get_pfn(l2_ro_mpt[l2_table_offset(va)]);
+            unsigned long pt_pfn = l2e_get_pfn(*pl2e);
+
             if ( hotadd_mem_valid(pt_pfn, info) )
             {
-                destroy_xen_mappings(rwva, rwva +
-                        (1UL << L2_PAGETABLE_SHIFT));
-                l2e_write(&l2_ro_mpt[l2_table_offset(va)], l2e_empty());
+                unsigned long rwva = RDWR_COMPAT_MPT_VIRT_START + off;
+
+                destroy_xen_mappings(rwva, rwva + (1UL << L2_PAGETABLE_SHIFT));
+                l2e_write(pl2e, l2e_empty());
             }
         }
 
@@ -316,10 +315,9 @@ static void destroy_m2p_mapping(struct mem_hotadd_info *info)
  */
 static int setup_compat_m2p_table(struct mem_hotadd_info *info)
 {
-    unsigned long i, va, smap, emap, rwva, epfn = info->epfn;
+    unsigned long i, smap, emap, epfn = info->epfn;
     mfn_t mfn;
     unsigned int n;
-    l2_pgentry_t *l2_ro_mpt = NULL;
     int err = 0;
 
     smap = info->spfn & (~((1UL << (L2_PAGETABLE_SHIFT - 2)) -1));
@@ -337,8 +335,6 @@ static int setup_compat_m2p_table(struct mem_hotadd_info *info)
     emap = ( (epfn + ((1UL << (L2_PAGETABLE_SHIFT - 2)) - 1 )) &
                 ~((1UL << (L2_PAGETABLE_SHIFT - 2)) - 1) );
 
-    l2_ro_mpt = compat_idle_pg_table_l2;
-
 #define MFN(x) (((x) << L2_PAGETABLE_SHIFT) / sizeof(unsigned int))
 #define CNT ((sizeof(*frame_table) & -sizeof(*frame_table)) / \
              sizeof(*compat_machine_to_phys_mapping))
@@ -347,13 +343,11 @@ static int setup_compat_m2p_table(struct mem_hotadd_info *info)
 
     for ( i = smap; i < emap; i += (1UL << (L2_PAGETABLE_SHIFT - 2)) )
     {
-        va = HIRO_COMPAT_MPT_VIRT_START +
-              i * sizeof(*compat_machine_to_phys_mapping);
-
-        rwva = RDWR_COMPAT_MPT_VIRT_START +
-                i * sizeof(*compat_machine_to_phys_mapping);
+        unsigned int off = i * sizeof(*compat_machine_to_phys_mapping);
+        l2_pgentry_t *pl2e = compat_idle_pg_table_l2 + l2_table_offset(off);
+        unsigned long rwva = RDWR_COMPAT_MPT_VIRT_START + off;
 
-        if (l2e_get_flags(l2_ro_mpt[l2_table_offset(va)]) & _PAGE_PRESENT)
+        if ( l2e_get_flags(*pl2e) & _PAGE_PRESENT )
             continue;
 
         for ( n = 0; n < CNT; ++n)
@@ -370,8 +364,7 @@ static int setup_compat_m2p_table(struct mem_hotadd_info *info)
         /* Fill with INVALID_M2P_ENTRY. */
         memset((void *)rwva, 0xFF, 1UL << L2_PAGETABLE_SHIFT);
         /* NB. Cannot be GLOBAL as the ptes get copied into per-VM space. */
-        l2e_write(&l2_ro_mpt[l2_table_offset(va)],
-                  l2e_from_mfn(mfn, _PAGE_PSE|_PAGE_PRESENT));
+        l2e_write(pl2e, l2e_from_mfn(mfn, _PAGE_PSE|_PAGE_PRESENT));
     }
 #undef CNT
 #undef MFN
@@ -620,7 +613,6 @@ void __init paging_init(void)
         goto nomem;
     compat_idle_pg_table_l2 = l2_ro_mpt;
     clear_page(l2_ro_mpt);
-    l2_ro_mpt += l2_table_offset(HIRO_COMPAT_MPT_VIRT_START);
     /* Allocate and map the compatibility mode machine-to-phys table. */
     mpt_size = (mpt_size >> 1) + (1UL << (L2_PAGETABLE_SHIFT - 1));
     if ( mpt_size > RDWR_COMPAT_MPT_VIRT_END - RDWR_COMPAT_MPT_VIRT_START )

diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 2d6393e64ea4500d7014e8f3fb05c662f8f067a4..266d2817189f835e63c4410121da919924573763 100644 (file)
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -215,11 +215,8 @@ extern unsigned char boot_edid_info[128];
 /* Slot 261: compatibility machine-to-phys conversion table (1GB). */
 #define RDWR_COMPAT_MPT_VIRT_START VMAP_VIRT_END
 #define RDWR_COMPAT_MPT_VIRT_END (RDWR_COMPAT_MPT_VIRT_START + GB(1))
-/* Slot 261: high read-only compat machine-to-phys conversion table (1GB). */
-#define HIRO_COMPAT_MPT_VIRT_START RDWR_COMPAT_MPT_VIRT_END
-#define HIRO_COMPAT_MPT_VIRT_END (HIRO_COMPAT_MPT_VIRT_START + GB(1))
 /* Slot 261: xen text, static data, bss, per-cpu stubs and executable fixmap (1GB). */
-#define XEN_VIRT_START          (HIRO_COMPAT_MPT_VIRT_END)
+#define XEN_VIRT_START          RDWR_COMPAT_MPT_VIRT_END
 #define XEN_VIRT_END            (XEN_VIRT_START + GB(1))
 
 #ifndef CONFIG_BIGMEM