WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] Re: [RFC PATCH 18/33] Subarch support for CPUID instruction

From: Zachary Amsden <zach@xxxxxxxxxx>
Date: Tue, 18 Jul 2006 04:33:52 -0700

> You really need a CPUID hook.  The instruction is non-virtualizable, and 
> anything claiming to be a hypervisor really has to support masking and 
> flattening the cpuid namespace for the instruction itself.  It is used 
> in assembler code and very early in boot.  The alternative is injecting 
> a bunch of Xen-specific code to filter feature bits into the i386 layer, 
> which is both bad for Linux and bad for Xen - and was quite ugly in the 
> last set of Xen patches.

Userspace will still see the full set of cpuid bits, since
it can still execute cpuid unimpeded, is this ok?

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>