From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.xen@gmail.com>
Subject: Re: Xen HVM regression on certain Intel CPUs
Date: Wed, 03 Apr 2013 15:28:05 +0100
Message-ID: <CD81FB05.1FD9A%keir.xen@gmail.com>
References: <515C402A02000078000CA55C@nat28.tlf.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <515C402A02000078000CA55C@nat28.tlf.novell.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Jan Beulich <JBeulich@suse.com>, Stefan Bader <stefan.bader@canonical.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Eddie Dong <eddie.dong@intel.com>, wei.y.yang@intel.com, haitao.shan@intel.com, Dongxiao Xu <dongxiao.xu@intel.com>, xin.li@intel.com, Jun Nakajima <jun.nakajima@intel.com>, "H. Peter Anvin" <hpa@zytor.com>, xiantao.zhang@intel.com
List-Id: xen-devel@lists.xenproject.org

On 03/04/2013 13:43, "Jan Beulich" <JBeulich@suse.com> wrote:

>>>> On 03.04.13 at 13:56, Stefan Bader <stefan.bader@canonical.com> wrote:
>> I added some more debugging output to the hypervisor to verify the state of
>> HAP.
>> This showed that while HAP is available on the system, it is not used for the
>> HVM guests. It looks like this would require some flags to be set when
>> creating
>> the guest domains and I assume this is not happening because I have to stay
>> with
>> the xm stack for the libvirt setup for now (requires some repackaging which
>> hasn't been done, yet).
>> 
>> So the guest isn't using HAP but does seem to use some form of paging even if
>> the guest VCPU is not using paging. So I changed the vmx_update_guest_cr()
>> function in that way and that seems to prevent the hangs. Does this look like
>> a
>> reasonable upstream Xen change?
> 
> Yes, it looks appropriate. But I'd like this to be confirmed by the
> authors of the original change and/or the VMX maintainers (added
> to Cc).

It can have my ack straight away.

Acked-by: Keir Fraser <keir@xen.org>

Nonetheless it would be nice to get a VMX maintainer ack too, though I'm
pretty sure this patch is correct.

 -- Keir

> Nevertheless it's very odd to not use HAP on a machine capable
> of it...
> 
> Jan
> 
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xen.org
> http://lists.xen.org/xen-devel