[Xen-changelog] [xen-4.1-testing] xen/libxc: set CPUID topology leaf as unsupported for PV guests

[Xen patchbot-4.1-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User David Vrabel <david.vrabel@xxxxxxxxxx>
# Date 1310805187 -3600
# Node ID 6a9d5d3b1b9e59a171402992fb7e59c8c4f32742
# Parent  edd38c84877e0a370d0d47c2c5c4447e435972bf
xen/libxc: set CPUID topology leaf as unsupported for PV guests

The result of a CPUID Extended Topology Enumeration leaf for PV guests
is invalid as the level in ECX is ignored.  This can cause some guests
to loop endlessly when trying to enumerate the topology.

Since the physical topology isn't useful to PV guests set the topology
leaf as unsupported.

Guests affected include Linux kernels prior 2.6.32 where a workaround
was applied ("xen: mask extended topology info in cpu",
82d6469916c6fcfa345636a49004c9d1753905d1).

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
xen-unstable changeset:   23700:867bb675b57b
xen-unstable date:        Sat Jul 16 09:05:45 2011 +0100
---


diff -r edd38c84877e -r 6a9d5d3b1b9e tools/libxc/xc_cpuid_x86.c
--- a/tools/libxc/xc_cpuid_x86.c        Fri Jul 08 08:57:45 2011 +0100
+++ b/tools/libxc/xc_cpuid_x86.c        Sat Jul 16 09:33:07 2011 +0100
@@ -465,6 +465,7 @@
 
     case 5: /* MONITOR/MWAIT */
     case 0xa: /* Architectural Performance Monitor Features */
+    case 0x0000000b: /* Extended Topology Enumeration */
     case 0x8000000a: /* SVM revision and features */
     case 0x8000001b: /* Instruction Based Sampling */
     case 0x8000001c: /* Light Weight Profiling */
diff -r edd38c84877e -r 6a9d5d3b1b9e xen/arch/x86/traps.c
--- a/xen/arch/x86/traps.c      Fri Jul 08 08:57:45 2011 +0100
+++ b/xen/arch/x86/traps.c      Sat Jul 16 09:33:07 2011 +0100
@@ -828,6 +828,7 @@
         /* fall through */
     case 5: /* MONITOR/MWAIT */
     case 0xa: /* Architectural Performance Monitor Features */
+    case 0x0000000b: /* Extended Topology Enumeration */
     case 0x8000000a: /* SVM revision and features */
     case 0x8000001b: /* Instruction Based Sampling */
     case 0x8000001c: /* Light Weight Profiling */

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