commit e802e47d85314b4541288e4a19d057e2ea885a28
Author: Andre Przywara <andre.przywara@xxxxxxx>
Date:   Tue May 22 15:13:07 2012 +0200

    filter APERFMPERF feature in Xen to avoid kernel internal usage
    
    Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 95dccce..71252d5 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -240,6 +240,11 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
 		*dx = cpuid_leaf5_edx_val;
 		return;
 
+	case 6:
+		/* Disabling APERFMPERF for kernel usage */
+		maskecx = ~(1U << 0);
+		break;
+
 	case 0xb:
 		/* Suppress extended topology stuff */
 		maskebx = 0;