Xen devel - Nov 2005 - [PATCH] fix issue of accessing supervisor page from ring3 in vmx guest

# HG changeset patch
# User Xiaofeng Ling <xiaofeng.ling@intel.com>
# Node ID b832c9f342065a84991b4fbf0e30749225995228
# Parent  ff879b0ac94170c3b1354fa5e297684ecffb834f
Fix vmx guest issue of allowing accessing supervisor page
from user level program.
In shadow fault, we need to check U/S bit in error code.
It is just a fix for shadow32.c, for x86_64 code and
public code, it is already handled.

Signed-off-by: Xiaofeng Ling <xiaofeng.ling@intel.com>

diff -r eb213ab53c9b xen/arch/x86/shadow32.c
--- a/xen/arch/x86/shadow32.c	Fri Nov 25 13:07:07 2005 +0800
+++ b/xen/arch/x86/shadow32.c	Fri Nov 25 13:47:48 2005 +0800
@@ -2693,6 +2693,16 @@
              domain_crash_synchronous();
          }

+        /* uer runlevel to access vilation error in guest? */
+        if ( unlikely((regs->error_code & 4) &&
+                      !(l1e_get_flags(gpte) & _PAGE_USER)))
+        {
+            SH_VVLOG("shadow_fault - EXIT: wr fault on super page (%"
PRIpte ")",
+                    l1e_get_intpte(gpte));
+            goto fail;
+
+        }
+
          if ( unlikely(!l1pte_write_fault(v, &gpte, &spte, va)) )
          {
              SH_VVLOG("shadow_fault - EXIT: l1pte_write_fault
failed");
@@ -2706,6 +2716,16 @@
      }
      else
      {
+        /* protection violation error(read) in guest? */
+        if ( unlikely((regs->error_code & 1) ))
+        {
+            SH_VVLOG("shadow_fault - EXIT: read fault on super page
(%"
PRIpte ")",
+                    l1e_get_intpte(gpte));
+            goto fail;
+
+        }
+
+
          if ( !l1pte_read_fault(d, &gpte, &spte) )
          {
              SH_VVLOG("shadow_fault - EXIT: l1pte_read_fault
failed");


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