From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32930) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VqR11-0001Jr-Qc for qemu-devel@nongnu.org; Tue, 10 Dec 2013 12:22:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VqR0v-0007YG-Qa for qemu-devel@nongnu.org; Tue, 10 Dec 2013 12:22:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36895) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VqR0v-0007Xy-I3 for qemu-devel@nongnu.org; Tue, 10 Dec 2013 12:22:29 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id rBAHMSUq030585 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 10 Dec 2013 12:22:28 -0500 Date: Tue, 10 Dec 2013 15:21:44 -0200 From: Marcelo Tosatti Message-ID: <20131210172144.GA29151@amt.cnet> References: <1385401393-14291-1-git-send-email-pbonzini@redhat.com> <20131128102652.GA24261@redhat.com> <52A714AC.3050703@redhat.com> <20131210150542.GA27998@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131210150542.GA27998@amt.cnet> Subject: Re: [Qemu-devel] [PATCH rebased for-1.8] i386: pc: align gpa<->hpa on 1GB boundary (v6) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" On Tue, Dec 10, 2013 at 01:05:42PM -0200, Marcelo Tosatti wrote: > On Tue, Dec 10, 2013 at 02:18:36PM +0100, Paolo Bonzini wrote: > > Il 28/11/2013 11:26, Michael S. Tsirkin ha scritto: > > > On Mon, Nov 25, 2013 at 06:43:13PM +0100, Paolo Bonzini wrote: > > >> v2: condition enablement of new mapping to new machine types (Paolo) > > >> v3: fix changelog > > >> v4: rebase > > >> v5: ensure alignment of piecetwo on 2MB GPA (Igor) > > >> do not register zero-sized piece-one (Igor) > > >> v6: fix memory leak (Igor) > > >> fix integer overflow (Igor) > > >> > > >> ---- > > >> > > >> Align guest physical address and host physical address > > >> beyond guest 4GB on a 1GB boundary. > > >> > > >> Otherwise 1GB TLBs cannot be cached for the range. > > >> > > >> Signed-off-by: Marcelo Tosatti > > >> [Reorganize code, keep same logic. - Paolo] > > >> Signed-off-by: Paolo Bonzini > > >> --- > > > > > > Applied, thanks. > > > > As discussed offlist, I'm not sure anymore that this is the right > > approach to the problem. No doubt it is very clever, in that it is > > absolutely transparent to the guest. However, the non-contiguous > > mapping of ram_addr_t makes it more complex to associate the right NUMA > > policy to the ranges. > > Please explain what is the difference, and why the complexity does not > exist with non-contiguous mapping of ram_addr_t. You are right - it forces the 1GB page which contains the hole to be on the same NUMA node as the tail 1GB page - otherwise incorrect NUMA assignment is not possible. Agreed. > > If we could make a small guset visible change, it would be simpler to > > always make the PCI hole 1GB in size; it is currently 256MB for i440FX > > and 1.25GB for q35. We can take a look as soon as the SeaBIOS patches > > are in to use QEMU-built ACPI tables. > > > > Paolo