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Re: [Xen-devel] [PATCH] x86: don't expose SYSENTER on unknown CPUs


  • To: Jan Beulich <JBeulich@xxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxx>
  • From: Keir Fraser <keir.xen@xxxxxxxxx>
  • Date: Fri, 17 Aug 2012 17:43:36 +0100
  • Delivery-date: Fri, 17 Aug 2012 16:43:56 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xen.org>
  • Thread-index: Ac18l3IcnnfTxNSj/0ygbGkwHoXmgQ==
  • Thread-topic: [Xen-devel] [PATCH] x86: don't expose SYSENTER on unknown CPUs

On 17/08/2012 17:25, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:

> 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>

> --- a/xen/arch/x86/cpu/common.c
> +++ b/xen/arch/x86/cpu/common.c
> @@ -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 = {
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel



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