Re: EFER in HVM guests

[Keir Fraser <keir@xensource.com>]

*Please* can you make the handling of generic CPUID leaves and architectural
MSRs common HVM code? There is lots of needless code duplication right now
with niggling differences that shouldn't be necessary.

 -- Keir

On 29/11/06 16:34, "Nakajima, Jun" <jun.nakajima@intel.com> wrote:

>> I think it does - allowing a guest to enable EFER.LME when the
>> hypervisor is a 32-bit one is clearly a security problem: While I
>> haven't tried it, I would suspect the moment you load a context
>> with such an EFER the whole system's dead.
>> Not being able to access EFER is also a potential problem, as a
>> guest should be allowed to set EFER.NX (at least) - the CPUID
>> handling code specifically does not suppress this bit if the guest
>> is allowed to use PAE (which we agreed a few days ago should
>> be the default anyway).
>> 
>> Jan
>> 
> 
> I agree that we should allow 32-bit guests to set EFER.NX on the PAE
> Xen. We'll fix it. EFER.SCE should not be set on IA-32.