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From: Keir Fraser <keir.fraser@eu.citrix.com>
To: Tim Deegan <Tim.Deegan@citrix.com>,
	Christoph Egger <Christoph.Egger@amd.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
	Qing He <qing.he@intel.com>
Subject: Re: Fwd: [PATCH 0/18] Nested Virtualization: Overview
Date: Fri, 16 Apr 2010 18:50:32 +0100	[thread overview]
Message-ID: <C7EE61F8.1182A%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <20100416102711.GA31304@whitby.uk.xensource.com>

On 16/04/2010 11:27, "Tim Deegan" <Tim.Deegan@citrix.com> wrote:

>> Please read the XenNestedHVM.pdf paper, particularly the section "Software
>> Architecture". This describes how this is made to be generic and what needs
>> to be done to adapt to Intel.
> 
> Your PDFs suggest that even on Intel CPUs, the nested hypervisor should
> always see SVM, not VMX.  You shouldn't be surprised or offended if that
> isn't popular with Intel. :)

I don't see any good argument for it either. I.e., I don't think we care
about migrating between AMD and Intel hosts with nestedhvm enabled, which I
think would be the only argument for it. I know we added support for
cross-emulating SYSENTER and SYSCALL, but that's needed for cross-migration
of any 64-bit guest running compat-mode apps (i.e., really need to make
cross-migration possible at all). I'm sceptical enough of the utility of
cross-vendor migration *at all*, let alone supporting in tandem with
advanced features also of dubious utility (at least in enterprise space),
like nestedhvm.

 -- Keir

  reply	other threads:[~2010-04-16 17:50 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-15 13:20 Fwd: [PATCH 0/18] Nested Virtualization: Overview Christoph Egger
2010-04-15 13:39 ` Vincent Hanquez
2010-04-15 14:50   ` Christoph Egger
2010-04-15 14:51   ` Christoph Egger
2010-04-15 14:57 ` Keir Fraser
2010-04-15 15:17   ` Christoph Egger
2010-04-15 16:26     ` Keir Fraser
2010-04-15 15:25   ` Tim Deegan
2010-04-16 10:01     ` Christoph Egger
2010-04-16  9:07 ` Qing He
2010-04-16  9:32   ` Christoph Egger
2010-04-16 10:27     ` Tim Deegan
2010-04-16 17:50       ` Keir Fraser [this message]
2010-04-20  2:07         ` Dong, Eddie
2010-04-17 11:43       ` Joerg Roedel
2010-04-18 17:52         ` Keir Fraser

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