From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:33675)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <haozhong.zhang@intel.com>) id 1bKgK8-0006vy-MO
	for qemu-devel@nongnu.org; Wed, 06 Jul 2016 02:28:41 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <haozhong.zhang@intel.com>) id 1bKgK4-0005nr-HS
	for qemu-devel@nongnu.org; Wed, 06 Jul 2016 02:28:39 -0400
Received: from mga11.intel.com ([192.55.52.93]:39727)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <haozhong.zhang@intel.com>) id 1bKgK4-0005nn-Bq
	for qemu-devel@nongnu.org; Wed, 06 Jul 2016 02:28:36 -0400
Date: Wed, 6 Jul 2016 14:28:32 +0800
From: Haozhong Zhang <haozhong.zhang@intel.com>
Message-ID: <20160706062832.py2denwwvhw24f52@hz-desktop>
References: <20160622065324.23812-1-haozhong.zhang@intel.com>
	<bd26755e-9bc5-de61-8f05-f5257be9a22d@redhat.com>
	<20160706012619.ebiizdoqngkmur7a@hz-desktop>
	<234271213.4215596.1467785884526.JavaMail.zimbra@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <234271213.4215596.1467785884526.JavaMail.zimbra@redhat.com>
Subject: Re: [Qemu-devel] [SeaBIOS] [PATCH v3] fw/msr_feature_control: add
 support to set MSR_IA32_FEATURE_CONTROL
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel/>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Ashok Raj <ashok.raj@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>, Laszlo Ersek <lersek@redhat.com>, seabios@seabios.org, qemu-devel@nongnu.org

Hi Ashok,

On 07/06/16 02:18, Paolo Bonzini wrote:
> > I forgot to restore MSR_IA32_FEATURE_CONTROL in the resume path, and
> > MSR_IA32_FEATURE_CONTROL is zero after S3 resume.
> 
> This is a bug.  Sorry Laszlo. :)
> 
> > Not restore MSR_IA32_FEATURE_CONTROL during S3 resume does not affect
> > at least Linux guest (tested 4.5). Current QEMU may advise the guest
> > firmware to set bit 20 (for LMCE), bit 2 (for VMX) and bit 0 (lock
> > bit).
> > - For LMCE, Linux only checks bit 20 and bit 0 at boot time and then
> >   keeps using the result even after resume.
> 
> On real hardware, LMCE would not be enabled after resume.  I'm not
> sure what would happen, but it wouldn't be good.

Could you help to check if the LMCE bit in MSR_IA32_FEATURE_CONTROL is
set after S3 resume on the real hardware?

Thanks,
Haozhong