[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] vmcs_revision_id: do we care?

  • To: Daniel Li <dli@xxxxxxxxxxxxxxx>
  • From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
  • Date: Wed, 09 Jan 2008 19:25:03 +0000
  • Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
  • Delivery-date: Wed, 09 Jan 2008 11:25:42 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: AchS9VU0k5SOyL7oEdy80AAWy6hiGQ==
  • Thread-topic: [Xen-devel] vmcs_revision_id: do we care?

Yes, it would be along those lines. Also HVM save/restore should probably
not be checking for identical CPU stepping number, if it's actually allowed
that steppings can differ even within the same machine!

It's probably not too hard to knock up for 3.2.1, and maybe in time for
3.1.3, but it's bound to have some performance impact (but only on
mixed-stepping systems). I'm not sure how much that impact will be.

 -- Keir

On 9/1/08 16:13, "Daniel Li" <dli@xxxxxxxxxxxxxxx> wrote:

> Based on what I've heard, both IBM and Intel have been telling people
> this configuration is valid.  From what I was able to dig out, Intel in
> their System Programming Guide: Virtual Machine Monitor Programming
> Considerations, published Nov. 2007, suggested when loading a VMCS onto
> a processor with a different vmcs_revision_id, instead of using VMPTRLD,
> one should use VMREAD to read out each field then use VMWRITE to write
> them back. Is that more or less  the kind of work we are facing here? Or
> is there more?
> Thanks,
> Dan
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.