From: Jan Beulich <jbeulich@suse.com>
Date: Mon, 20 Aug 2012 06:40:01 +0000 (+0200)
Subject: x86: don't expose SYSENTER on unknown CPUs
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~8040
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=798f90e005767407a97f68cf5b95168fb44a46b4;p=xen.git

x86: don't expose SYSENTER on unknown CPUs

So far we only ever set up the respective MSRs on Intel CPUs, yet we
hide the feature only on a 32-bit hypervisor. That prevents booting of
PV guests on top of a 64-bit hypervisor making use of the instruction
on unknown CPUs (VIA in this case).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
---

diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 186863d131..d066ebbcec 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -55,6 +55,7 @@ static void default_init(struct cpuinfo_x86 * c)
 	/* Not much we can do here... */
 	/* Check if at least it has cpuid */
 	BUG_ON(c->cpuid_level == -1);
+	__clear_bit(X86_FEATURE_SEP, c->x86_capability);
 }
 
 static struct cpu_dev default_cpu = {