From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Tripathy Subject: Re: Can't see more than 3.5GB of RAM / UEFI / no e820 memory map detected Date: Fri, 24 Aug 2012 18:39:42 +0100 Message-ID: <5037BC5E.3010806@abpni.co.uk> References: <50356E43.3030208@abpni.co.uk> <50356FB1.2070904@abpni.co.uk> <20120823060620.GE19851@reaktio.net> <20120823072218.GF19851@reaktio.net> <5035DB70.8090800@abpni.co.uk> <5035EC5A020000780008A62A@nat28.tlf.novell.com> <9eb3fd179342b6962f057e499b375c4e@abpni.co.uk> <5037AD6A020000780008A79D@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5037AD6A020000780008A79D@nat28.tlf.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: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 24/08/2012 16:35, Jan Beulich wrote: >>>> On 23.08.12 at 10:07, Jonathan Tripathy wrote: >> On 23.08.2012 08:39, Jan Beulich wrote: >>>>>> Jonathan Tripathy 08/23/12 9:29 AM >>> >>>> I'm guessing xen.efi (from 4.2) just replaces grub?? >>> "Replaces" is the wrong term. It simply makes the use of grub.efi (or >>> however >>> it's named) unnecessary. >>> >>>> Also, if I were to apply that patch from superuser >>>> (http://serverfault.com/questions/342109/xen-only-sees-512mb-of-system-ram-sh >> ould-be-8gb-uefi-boot), >>>> would have have any bad consequences? I'm very security conscience as >>>> the DomUs are untrusted... >>> If you wanted to do that, I'd strongly recommend only removing the >>> E801 code >>> (obviously, from your log, you don't get E820 entries reported >>> anyway, so this >>> would be to not harm using hypervisors built from the same source on >>> other >>> systems) or simply swapping the E801 and multiboot handling order >>> (which may >>> actually be something to consider even upstream, so you'd be welcome >>> to post >>> such a patch). >>> >>> But in the end, in order to indeed use UEFI as intended, you'll need >>> to switch to >>> using xen.efi and an EFI-enabled Dom0 kernel (which upstream pv-ops >>> for now >>> isn't). >> I'll submit a patch with the map entries in the if block swapped. I'll >> make the patch, then test it for you guys, then post it. Do I just send >> it to this list (for the benefit of others and for upstream >> consideration)? > Yes. > >> When you say "use UEFI as intended", is there something wrong with just >> flipping the if block on its head? > That flipping has nothing to do with UEFI, just with the way grub.efi > works. > > Proper UEFI support implies use of EFI's boot and run time services, > which only xen.efi currently does (and which, for those run time > services that get made available for use by Dom0, also requires an > enabled Dom0 kernel). > Thanks for the clarification. So from a security/reliability standpoint, nothing will be affected by flipping the if block? Sorry that I haven't submitted the patch yet, just been very busy. This is on my to-do list this weekend. Thanks