From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH] x86: add feature flags to shared_info page Date: Mon, 2 Mar 2015 13:44:45 +0000 Message-ID: <54F4694D.3010808@citrix.com> References: <1425301144-27119-1-git-send-email-jgross@suse.com> <54F470740200007800065076@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 1YSQeQ-0006fl-Ic for xen-devel@lists.xenproject.org; Mon, 02 Mar 2015 13:44:50 +0000 In-Reply-To: <54F470740200007800065076@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 , Juergen Gross Cc: keir@xen.org, Ian.Campbell@citrix.com, ian.jackson@eu.citrix.com, tim@xen.org, david.vrabel@citrix.com, xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org On 02/03/15 13:15, Jan Beulich wrote: >>>> On 02.03.15 at 13:59, <"jgross@suse.com".non-mime.internet> wrote: >> In order to indicate the Xen tools capability to support the virtual >> mapped linear p2m list instead the 3 level mfn tree add feature flags >> to the shared_info page. > But why in the shared info page? They'd belong to start info or should > be obtainable via XENVER_get_features. Furthermore in this case, the virtual linear p2m is purely a guest->toolstack feature/ABI. Xen deliberately has no knowledge of PV guest p2ms of either the 3level or linear variety. Is there genuinely no better interface than the hypervisor feature flags to indicate a piece of toolstack support? ~Andrew