From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v5 8/9] tools: arm: support up to (almost) 1TB of guest RAM Date: Thu, 22 May 2014 11:25:03 +0100 Message-ID: <537DD07F.5020101@linaro.org> References: <1400751582.11409.46.camel@kazak.uk.xensource.com> <1400752004-9731-8-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1400752004-9731-8-git-send-email-ian.campbell@citrix.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: Ian Campbell , tim@xen.org, stefano.stabellini@eu.citrix.com, ian.jackson@eu.citrix.com Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org Hi Ian, On 22/05/14 10:46, Ian Campbell wrote: > This creates a second bank of RAM starting at 8GB and potentially > extending to the 1TB boundary, which is the limit imposed by our > current use of a 3 level p2m with 2 pages at level 0 (2^40 bits). > > I've deliberately left a gap between the two banks just to > exercise those code paths. > > The second bank is 1016GB in size which plus the 3GB below 4GB is > 1019GB maximum guest RAM. At the point where the fact that this > is slightly less than a full TB starts to become an issue for > people then we can switch to a 4 level p2m, which would be needed > to support guests larger than 1TB anyhow. > > Tested on 32-bit with 1, 4 and 6GB guests. Anything more than > ~3GB requires an LPAE enabled kernel, or a 64-bit guest. > > Signed-off-by: Ian Campbell Acked-by: Julien Grall -- Julien Grall