From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: Re: [PATCH v2] docs: add PVH specification Date: Thu, 18 Sep 2014 17:03:45 +0100 Message-ID: <541B0261.5080904@citrix.com> References: <1411054066-3677-1-git-send-email-roger.pau@citrix.com> <541B1CFD020000780003643F@mail.emea.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1XUeBX-0004aV-EZ for xen-devel@lists.xenproject.org; Thu, 18 Sep 2014 16:03:55 +0000 In-Reply-To: <541B1CFD020000780003643F@mail.emea.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Jan Beulich , Roger Pau Monne Cc: xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org On 18/09/14 16:57, Jan Beulich wrote: >>>> On 18.09.14 at 17:27, wrote: >> +All the segments selectors are set with a flat base at zero. >> + >> +The `cs` segment selector attributes are set to 0x0a09b, which describes an >> +executable and readable code segment only accessible by the most privileged >> +level. The segment is also set as a 64-bit code segment (`L` flag set) with a >> +default operation size of 16bits (`D` flag unset). > > There's no such thing - the L bit set requires the D bit to be clear > _without_ this meaning a default operation size of 16 bits. > >> +The remaining segment selectors (`ds`, `ss`, `es`, `fs` and `gs`) are all set >> +to the same values. The attributes are set to 0x0c093, which implies a read and >> +write data segment only accessible by the most privileged level. It is important >> +to notice that for the `ss` selector the stack is set to use a 32bit pointer >> +(`B` flag set). > > The B bit really has no meaning in 64-bit mode, and the stack pointer > will always be a 64-bit one. Perhaps this doc should avoid explaining what the bits mean? The Intel or AMD reference manuals can be used for this. David