[Xen-devel] [PATCH 6/6] Change MMU_PT_UPDATE_RESERVE_AD to support update page table for foreign domain

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Currently MMU_PT_UPDATE_RESERVE_AD support only update page table for current 
domain. This patch add support for foreign domain also.

Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx> Update the page table 
update hypercall

diff -r f6457425560b xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c Wed May 27 03:22:43 2009 +0800
+++ b/xen/arch/x86/mm.c Wed May 27 03:40:38 2009 +0800
@@ -110,6 +110,7 @@
 #include <asm/hypercall.h>
 #include <asm/shared.h>
 #include <public/memory.h>
+#include <public/sched.h>
 #include <xsm/xsm.h>
 #include <xen/trace.h>
 
@@ -2990,7 +2991,8 @@ int do_mmu_update(
     struct page_info *page;
     int rc = 0, okay = 1, i = 0;
     unsigned int cmd, done = 0;
-    struct domain *d = current->domain;
+    struct domain *d = current->domain, *pt_owner = NULL;
+    struct vcpu *v = current;
     struct domain_mmap_cache mapcache;
 
     if ( unlikely(count & MMU_UPDATE_PREEMPTED) )
@@ -3051,10 +3053,35 @@ int do_mmu_update(
             gmfn = req.ptr >> PAGE_SHIFT;
             mfn = gmfn_to_mfn(d, gmfn);
 
-            if ( unlikely(!get_page_from_pagenr(mfn, d)) )
+            if (!mfn_valid(mfn))
+                mfn = gmfn_to_mfn(FOREIGNDOM, gmfn);
+            if (!mfn_valid(mfn))
             {
                 MEM_LOG("Could not get page for normal update");
                 break;
+            }
+
+            pt_owner = page_get_owner_and_reference(mfn_to_page(mfn));
+
+            if ( pt_owner != d )
+            {
+                if ( pt_owner == FOREIGNDOM )
+                {
+                    spin_lock(&FOREIGNDOM->shutdown_lock);
+                    if ( !IS_PRIV(d) ||
+                         !FOREIGNDOM->is_shut_down ||
+                          (FOREIGNDOM->shutdown_code != SHUTDOWN_suspend) )
+                    {
+                        spin_unlock(&FOREIGNDOM->shutdown_lock);
+                        rc = -EPERM;
+                        break;
+                    }
+                    v = FOREIGNDOM->vcpu[0];
+                }else
+                {
+                    rc = -EPERM;
+                    break;
+                }
             }
 
             va = map_domain_page_with_cache(mfn, &mapcache);
@@ -3070,24 +3097,21 @@ int do_mmu_update(
                 {
                     l1_pgentry_t l1e = l1e_from_intpte(req.val);
                     okay = mod_l1_entry(va, l1e, mfn,
-                                        cmd == MMU_PT_UPDATE_PRESERVE_AD,
-                                        current);
+                                        cmd == MMU_PT_UPDATE_PRESERVE_AD, v);
                 }
                 break;
                 case PGT_l2_page_table:
                 {
                     l2_pgentry_t l2e = l2e_from_intpte(req.val);
                     okay = mod_l2_entry(va, l2e, mfn,
-                                        cmd == MMU_PT_UPDATE_PRESERVE_AD,
-                                        current);
+                                        cmd == MMU_PT_UPDATE_PRESERVE_AD, v);
                 }
                 break;
                 case PGT_l3_page_table:
                 {
                     l3_pgentry_t l3e = l3e_from_intpte(req.val);
                     rc = mod_l3_entry(va, l3e, mfn,
-                                      cmd == MMU_PT_UPDATE_PRESERVE_AD, 1,
-                                      current);
+                                      cmd == MMU_PT_UPDATE_PRESERVE_AD, 1, v);
                     okay = !rc;
                 }
                 break;
@@ -3096,8 +3120,7 @@ int do_mmu_update(
                 {
                     l4_pgentry_t l4e = l4e_from_intpte(req.val);
                     rc = mod_l4_entry(va, l4e, mfn,
-                                      cmd == MMU_PT_UPDATE_PRESERVE_AD, 1,
-                                      current);
+                                      cmd == MMU_PT_UPDATE_PRESERVE_AD, 1, v);
                     okay = !rc;
                 }
                 break;
@@ -3105,7 +3128,7 @@ int do_mmu_update(
                 case PGT_writable_page:
                     perfc_incr(writable_mmu_updates);
                     okay = paging_write_guest_entry(
-                        current, va, req.val, _mfn(mfn));
+                        v, va, req.val, _mfn(mfn));
                     break;
                 }
                 page_unlock(page);
@@ -3116,11 +3139,13 @@ int do_mmu_update(
             {
                 perfc_incr(writable_mmu_updates);
                 okay = paging_write_guest_entry(
-                    current, va, req.val, _mfn(mfn));
+                    v, va, req.val, _mfn(mfn));
                 put_page_type(page);
             }
 
             unmap_domain_page_with_cache(va, &mapcache);
+            if (pt_owner != d)
+                spin_unlock(&FOREIGNDOM->shutdown_lock);
             put_page(page);
             break;
 
diff -r f6457425560b xen/include/public/xen.h
--- a/xen/include/public/xen.h  Wed May 27 03:22:43 2009 +0800
+++ b/xen/include/public/xen.h  Wed May 27 03:26:46 2009 +0800
@@ -170,6 +170,8 @@ DEFINE_XEN_GUEST_HANDLE(xen_pfn_t);
  * table entry is valid/present, the mapped frame must belong to the FD, if
  * an FD has been specified. If attempting to map an I/O page then the
  * caller assumes the privilege of the FD.
+ * The page table entry normally belongs to the calling domain. Otherwise it
+ * should belong to the FD and the FD should be suspended already
  * FD == DOMID_IO: Permit /only/ I/O mappings, at the priv level of the caller.
  * FD == DOMID_XEN: Map restricted areas of Xen's heap space.
  * ptr[:2]  -- Machine address of the page-table entry to modify.

Attachment: update_pt.patch
Description: update_pt.patch

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