From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH 4/6] libxc: expose xsaves/xgetbv1/xsavec to hvm guest Date: Fri, 17 Jul 2015 11:47:10 +0100 Message-ID: <55A8F94E0200007800092699@mail.emea.novell.com> References: <1437118016-25547-1-git-send-email-shuai.ruan@intel.com> <1437118016-25547-5-git-send-email-shuai.ruan@intel.com> <55A8CF380200007800092561@mail.emea.novell.com> <1F1902FEECF0C94391E82D1DBE2E72BDB34B59@shsmsx102.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1F1902FEECF0C94391E82D1DBE2E72BDB34B59@shsmsx102.ccr.corp.intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Shuai Ruan Cc: Kevin Tian , "wei.liu2@citrix.com" , Eddie Dong , "stefano.stabellini@eu.citrix.com" , "andrew.cooper3@citrix.com" , "ian.jackson@eu.citrix.com" , "xen-devel@lists.xen.org" , Jun Nakajima , "keir@xen.org" , "Ian.Campbell@citrix.com" List-Id: xen-devel@lists.xenproject.org >>> On 17.07.15 at 10:10, wrote: > Ok, Thanks Jan. > I will add the descriptions in next version. > > Below is the short descriptions. > For CPUID with eax=0xd and ecx=0x1, ebx\ecx\edx may not be zero when xsaves > supported. Also with ecx>2, ecx\edx may not be zero. If we want expose xsaves > to HVM guest , we should not set them to zero. > > So in your opinions ,is it proper to add these code here? Sure, provided you don't leak any bits that may become defined in the future, and the non-zero setting of which might be inconsistent with other CPUID data. I.e. without looking at the manual, I'd guess the above is still a little too vague. Jan