[Xen-changelog] [xen-unstable] x86_emulate: protmode_load_seg() cannot load system segments in long mode.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1249635283 -3600
# Node ID 71d6d6f2ecd6e4a33b7dc1363e0dfe6b89dcc416
# Parent  b9cdcf502aa35818581d41cee7e6e30ae49acb92
x86_emulate: protmode_load_seg() cannot load system segments in long mode.

Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/x86_emulate/x86_emulate.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff -r b9cdcf502aa3 -r 71d6d6f2ecd6 xen/arch/x86/x86_emulate/x86_emulate.c
--- a/xen/arch/x86/x86_emulate/x86_emulate.c    Thu Aug 06 11:14:48 2009 +0100
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c    Fri Aug 07 09:54:43 2009 +0100
@@ -1037,8 +1037,17 @@ protmode_load_seg(
         goto raise_exn;
     }
 
-    /* System segments must have the system flag (S) set. */
-    if ( (desc.b & (1u<<12)) == (!is_x86_user_segment(seg) << 12) )
+    if ( !is_x86_user_segment(seg) )
+    {
+        /* System segments must have S flag == 0. */
+        if ( desc.b & (1u << 12) )
+            goto raise_exn;
+        /* We do not support 64-bit descriptor types. */
+        if ( in_longmode(ctxt, ops) )
+            return X86EMUL_UNHANDLEABLE;
+    }
+    /* User segments must have S flag == 1. */
+    else if ( !(desc.b & (1u << 12)) )
         goto raise_exn;
 
     dpl = (desc.b >> 13) & 3;

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