From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [Xen-devel] [PATCH 06/11] xen/mmu: For 64-bit do not call xen_map_identity_early Date: Mon, 20 Aug 2012 08:06:49 -0400 Message-ID: <20120820120649.GI13755@localhost.localdomain> References: <1345133009-21941-1-git-send-email-konrad.wilk@oracle.com> <1345133009-21941-7-git-send-email-konrad.wilk@oracle.com> <20120817174549.GA14257@phenom.dumpdata.com> <1345463624.28762.67.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Stefano Stabellini Cc: Ian Campbell , "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Mon, Aug 20, 2012 at 12:58:37PM +0100, Stefano Stabellini wrote: > On Mon, 20 Aug 2012, Ian Campbell wrote: > > On Mon, 2012-08-20 at 12:45 +0100, Stefano Stabellini wrote: > > > On Fri, 17 Aug 2012, Konrad Rzeszutek Wilk wrote: > > > > On Fri, Aug 17, 2012 at 06:41:23PM +0100, Stefano Stabellini wrote: > > > > > On Thu, 16 Aug 2012, Konrad Rzeszutek Wilk wrote: > > > > > > B/c we do not need it. During the startup the Xen provides > > > > > > us with all the memory mapped that we need to function. > > > > > > > > > > Shouldn't we check to make sure that is actually true (I am thinking at > > > > > nr_pt_frames)? > > > > > > > > I was looking at the source code (hypervisor) to figure it out and > > > > that is certainly true. > > > > > > > > > > > > > Or is it actually stated somewhere in the Xen headers? > > > > > > > > Couldn't find it, but after looking so long at the source code > > > > I didn't even bother looking for it. > > > > > > > > Thought to be honest - I only looked at how the 64-bit pagetables > > > > were set up, so I didn't dare to touch the 32-bit. Hence the #ifdef > > > > > > I think that we need to involve some Xen maintainers and get this > > > written down somewhere in the public headers, otherwise we have no > > > guarantees that it is going to stay as it is in the next Xen versions. > > > > > > Maybe we just need to add a couple of lines of comment to > > > xen/include/public/xen.h. > > > > The start of day memory layout for PV guests is written down in the > > comment just before struct start_info at > > http://xenbits.xen.org/docs/unstable/hypercall/include,public,xen.h.html#Struct_start_info > > > > (I haven't read this thread to determine if what is documented matches > > what you guys are talking about relying on) > > but it is not written down how much physical memory is going to be > mapped in the bootstrap page tables. Considering that only pvops kernel has this change I think we are ok? > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel