From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41214) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bkGxZ-0002Js-Ue for qemu-devel@nongnu.org; Wed, 14 Sep 2016 16:39:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bkGxV-00031U-T5 for qemu-devel@nongnu.org; Wed, 14 Sep 2016 16:39:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49914) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bkGxV-00030z-MO for qemu-devel@nongnu.org; Wed, 14 Sep 2016 16:39:05 -0400 References: <147377800565.11859.4411044563640180545.stgit@brijesh-build-machine> <147377822450.11859.5845767550630184079.stgit@brijesh-build-machine> <45717d25-176b-dd80-98cc-d91ee0e354fc@redhat.com> <4785aa6b-9033-cced-2436-f25a099061cf@amd.com> From: Paolo Bonzini Message-ID: Date: Wed, 14 Sep 2016 22:38:58 +0200 MIME-Version: 1.0 In-Reply-To: <4785aa6b-9033-cced-2436-f25a099061cf@amd.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC PATCH v1 22/22] loader: reload bios image on ROM reset in SEV-enabled guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Brijesh Singh , ehabkost@redhat.com, crosthwaite.peter@gmail.com, armbru@redhat.com, mst@redhat.com, p.fedin@samsung.com, qemu-devel@nongnu.org, lcapitulino@redhat.com, rth@twiddle.net On 14/09/2016 22:29, Brijesh Singh wrote: >> Does the guest have to check the measured data (e.g. with a hash) too, >> to check that it hasn't been tampered with outside the secure >> processor's control? Of course this would result in garbage written to >> the modified page, but that might be a valid attack vector. > > Guest does not need to check the measurement. Can you explain why not? Paolo