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RE: [Xen-devel] HW Virtualization Abstraction Layer Work Underway

To: "Wahlig, Elsie" <elsie.wahlig@xxxxxxx>, <Xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] HW Virtualization Abstraction Layer Work Underway
From: "Nakajima, Jun" <jun.nakajima@xxxxxxxxx>
Date: Mon, 6 Jun 2005 01:15:44 -0700
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Thread-topic: [Xen-devel] HW Virtualization Abstraction Layer Work Underway
Wahlig, Elsie wrote:
> Tom Woller and I from AMD have been working with Ian, Keir and IBM on
> scoping out a plan that will provide a common interface to the user
> for both the Intel VT/VMX and the AMD Pacifica/SVM platforms.
> A key concept of the  proposal is the creation of a HW Virtualization
> Layer (called HVAL), which we describe below. We are still working out
> some of the arcane details offline and are discussing it with Sunil
> from Intel for a joint proposal.

We are evaluating this proposal and will work on enhancing the VT-x code
to provide the right level of abstraction to support other VT-x like

[Personal opinion] Since the handling of the CPU architectural state (as
handled by vmx.c and vmx_vmcs.c today, for example) is specific to each
virtualization technology and can be optimized more if the code is aware
of the technolgy, for a common interface I think we should focus on the
virtual platform area (i.e. configration definition & domain builder,
device models, I/O request notifcation, I/O VMEXIT handler, instruction
decoder for MMIO, etc.), rather than dealing with broader or vague "HW
Virtualization." That architecture in Xen is independent of VT-x or VT-x
does not define such area, thus it can/should be open to other H/W
assist virtualization technologies. In fact it was designed to support
VT-i (H/W assist virtualization on Itanium) as well. 

> Elsie Wahlig

Intel Open Source Technology Center

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