From: kaf24@firebug.cl.cam.ac.uk <kaf24@firebug.cl.cam.ac.uk>
Date: Thu, 25 Aug 2005 17:15:41 +0000 (+0000)
Subject: Fix MPT mapping for x86/64. Also i386 no longer needs
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~16844^2
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=5f2853adb1e8cf8d629b1160ab0a8437823d35cc;p=xen.git

Fix MPT mapping for x86/64. Also i386 no longer needs
4MB mapping for PAE, as xenlinux can handle faults when
accessing unmapped sections of the table.

Signed-off-by: Keir Fraser <keir@xensource.com>
---

diff --git a/xen/arch/x86/x86_32/mm.c b/xen/arch/x86/x86_32/mm.c
index 66fde57f20..bd67cf5421 100644
--- a/xen/arch/x86/x86_32/mm.c
+++ b/xen/arch/x86/x86_32/mm.c
@@ -93,15 +93,10 @@ void __init paging_init(void)
 
     /*
      * Allocate and map the machine-to-phys table and create read-only mapping 
-     * of MPT for guest-OS use.  Without PAE we'll end up with one 4MB page, 
-     * with PAE we'll allocate 2MB pages depending on the amount of memory 
-     * installed, but at least 4MB to cover 4GB address space.  This is needed 
-     * to make PCI I/O memory address lookups work in guests.
+     * of MPT for guest-OS use.
      */
     mpt_size  = (max_page * 4) + (1UL << L2_PAGETABLE_SHIFT) - 1UL;
     mpt_size &= ~((1UL << L2_PAGETABLE_SHIFT) - 1UL);
-    if ( mpt_size < (4 << 20) )
-        mpt_size = 4 << 20;
     for ( i = 0; i < (mpt_size >> L2_PAGETABLE_SHIFT); i++ )
     {
         if ( (pg = alloc_domheap_pages(NULL, PAGETABLE_ORDER, 0)) == NULL )
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index 10ee07b2d7..5233c92b9f 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -74,7 +74,7 @@ l2_pgentry_t *virt_to_xen_l2e(unsigned long v)
 
 void __init paging_init(void)
 {
-    unsigned long i;
+    unsigned long i, mpt_size;
     l3_pgentry_t *l3_ro_mpt;
     l2_pgentry_t *l2_ro_mpt;
     struct pfn_info *pg;
@@ -98,16 +98,17 @@ void __init paging_init(void)
      * Allocate and map the machine-to-phys table.
      * This also ensures L3 is present for fixmaps.
      */
-    for ( i = 0; i < max_page; i += ((1UL << L2_PAGETABLE_SHIFT) / 4) )
+    mpt_size  = (max_page * 4) + (1UL << L2_PAGETABLE_SHIFT) - 1UL;
+    mpt_size &= ~((1UL << L2_PAGETABLE_SHIFT) - 1UL);
+    for ( i = 0; i < (mpt_size >> L2_PAGETABLE_SHIFT); i++ )
     {
-        pg = alloc_domheap_pages(NULL, PAGETABLE_ORDER, 0);
-        if ( pg == NULL )
+        if ( (pg = alloc_domheap_pages(NULL, PAGETABLE_ORDER, 0)) == NULL )
             panic("Not enough memory for m2p table\n");
         map_pages_to_xen(
-            RDWR_MPT_VIRT_START + i*8, page_to_pfn(pg), 
+            RDWR_MPT_VIRT_START + (i << L2_PAGETABLE_SHIFT), page_to_pfn(pg), 
             1UL << PAGETABLE_ORDER,
             PAGE_HYPERVISOR);
-        memset((void *)(RDWR_MPT_VIRT_START + i*8), 0x55,
+        memset((void *)(RDWR_MPT_VIRT_START + (i << L2_PAGETABLE_SHIFT)), 0x55,
                1UL << L2_PAGETABLE_SHIFT);
         *l2_ro_mpt++ = l2e_from_page(
             pg, _PAGE_GLOBAL|_PAGE_PSE|_PAGE_USER|_PAGE_PRESENT);