[Xen-changelog] [xen-unstable] x86: don't expose SYSENTER on unknown CPUs

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1345444801 -7200
# Node ID 4b0d263008cdf4585fe30ec2847b0a810db12354
# Parent  73ac4b7ad2e14bf468fe7d4d032c80c6bd7350ad
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@xxxxxxxx>
Acked-by: Keir Fraser <keir@xxxxxxx>
---


diff -r 73ac4b7ad2e1 -r 4b0d263008cd xen/arch/x86/cpu/common.c
--- a/xen/arch/x86/cpu/common.c Fri Aug 17 14:57:29 2012 +0100
+++ b/xen/arch/x86/cpu/common.c Mon Aug 20 08:40:01 2012 +0200
@@ -55,6 +55,7 @@ static void default_init(struct cpuinfo_
        /* 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 = {

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