From mboxrd@z Thu Jan 1 00:00:00 1970 From: Abhinav Srivastava Subject: Re: Last Branch Record (LBR) in Xen Date: Fri, 26 Jun 2009 19:48:48 +0530 (IST) Message-ID: <713560.81367.qm@web7908.mail.in.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org =0AHi Jan,=0A=0AI got it now. Thanks for the clarification. However, could = you please=0Agive me some pointers or suggestions to code this thing in the= hypervisor?=0A=0AThanks,=0AAbhinav=0A=0A--- On Fri, 26/6/09, Jan Beulich <= JBeulich@novell.com> wrote:=0A=0A> From: Jan Beulich = =0A> Subject: Re: [Xen-devel] Last Branch Record (LBR) in Xen=0A> To: "Abhi= nav Srivastava" =0A> Cc: xen-devel@lists.xenso= urce.com=0A> Date: Friday, 26 June, 2009, 7:31 PM=0A> >>> Abhinav Srivastav= a=0A> =0A> 26.06.09 15:50 >>>=0A> >As far as I= understand (please correct me if I am=0A> wrong), you meant that HVM guest= s have to enable the LBR=0A> recording, and=0A> >this action cannot be init= iated/controlled by Xen. I=0A> was thinking like other kind of actions, suc= h as single=0A> stepping on instruction,=0A> >single stepping on branch etc= . that can be controlled=0A> from the hypervisor and guests behave accordin= gly, the LBR=0A> feature can=0A> >also be set/reset from the hypervisor. An= d, if that is=0A> not the case then I think any malicious programs can turn= =0A> off this feature=0A> >inside HVM guests and can bypass the debugger.= =0A> Moreover, I assumed anything that a guest can do, can also=0A> be done= from=0A> >the hypervisor by setting guest MSR registers or bitmap=0A> from= the hypervisor.=0A> =0A> Oh, of course this can be done from the hyperviso= r, but=0A> that wasn't the purpose of the patch. You'd have to code=0A> thi= s for yourself.=0A> =0A> Jan=0A> =0A> =0A> ________________________________= _______________=0A> Xen-devel mailing list=0A> Xen-devel@lists.xensource.co= m=0A> http://lists.xensource.com/xen-devel=0A> =0A=0A=0A Cricket on yo= ur mind? Visit the ultimate cricket website. Enter http://cricket.yahoo.com