From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Han, Huaitong" <huaitong.han@intel.com>
Subject: Re: [PATCH V4 6/6] x86/hvm: pkeys,
 add pkeys support for cpuid handling
Date: Tue, 22 Dec 2015 09:25:45 +0000
Message-ID: <1450776352.4024.19.camel@intel.com>
References: <1450682504-32286-1-git-send-email-huaitong.han@intel.com>
	<1450682504-32286-7-git-send-email-huaitong.han@intel.com>
	<567823CE02000078000C1F87@prv-mh.provo.novell.com>
	<1450752885.4024.4.camel@intel.com>
	<5679182F02000078000C21F9@prv-mh.provo.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: <5679182F02000078000C21F9@prv-mh.provo.novell.com>
Content-Language: en-US
Content-ID: <C03EA527BA663F498974C73620617D72@intel.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: "JBeulich@suse.com" <JBeulich@suse.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>, "wei.liu2@citrix.com" <wei.liu2@citrix.com>, "ian.campbell@citrix.com" <ian.campbell@citrix.com>, "stefano.stabellini@eu.citrix.com" <stefano.stabellini@eu.citrix.com>, "george.dunlap@eu.citrix.com" <george.dunlap@eu.citrix.com>, "andrew.cooper3@citrix.com" <andrew.cooper3@citrix.com>, "ian.jackson@eu.citrix.com" <ian.jackson@eu.citrix.com>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, "Nakajima,
	Jun" <jun.nakajima@intel.com>, "keir@xen.org" <keir@xen.org>
List-Id: xen-devel@lists.xenproject.org

On Tue, 2015-12-22 at 01:30 -0700, Jan Beulich wrote:
> > > > On 22.12.15 at 03:54, <huaitong.han@intel.com> wrote:
> > On Mon, 2015-12-21 at 08:07 -0700, Jan Beulich wrote:
> > > > > > On 21.12.15 at 08:21, <huaitong.han@intel.com> wrote:
> > > > @@ -4600,6 +4600,14 @@ void hvm_cpuid(unsigned int input,
> > > > unsigned
> > > > int *eax, unsigned int *ebx,
> > > >          /* Don't expose INVPCID to non-hap hvm. */
> > > >          if ( (count == 0) && !hap_enabled(d) )
> > > >              *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
> > > > +
> > > > +        /* X86_FEATURE_PKU is not yet implemented for shadow
> > > > paging. */
> > > > +        if ( (count == 0) && !hap_enabled(d) )
> > > > +            *ecx &= ~cpufeat_mask(X86_FEATURE_PKU);
> > > 
> > > I'm still missing the xsave dependency here.
> > Xsave dependency deletion becasue we use RDPKRU to get PKRU
> > register
> > value instead of XSAVE now.
> 
> What the hypervisor does doesn't matter here. The question is
> whether from an architectural standpoint XSAVE is a prerequsite.
> If it is, then you need to clear PKU when _guest_ XSAVE is clear.
No, XSAVE is not a prerequsite.
> 
> Jan
>