From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43576) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKO50-0006sc-Pt for qemu-devel@nongnu.org; Tue, 05 Jul 2016 06:59:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bKO4w-0005YD-Mh for qemu-devel@nongnu.org; Tue, 05 Jul 2016 06:59:49 -0400 Received: from mail-wm0-x242.google.com ([2a00:1450:400c:c09::242]:33735) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKO4w-0005Y3-G0 for qemu-devel@nongnu.org; Tue, 05 Jul 2016 06:59:46 -0400 Received: by mail-wm0-x242.google.com with SMTP id r201so27798874wme.0 for ; Tue, 05 Jul 2016 03:59:45 -0700 (PDT) Sender: Paolo Bonzini References: <1467659769-15900-1-git-send-email-dgilbert@redhat.com> <20160704231009-mutt-send-email-mst@redhat.com> <20160705093324.GC2118@work-vm> <20160705130015-mutt-send-email-mst@redhat.com> From: Paolo Bonzini Message-ID: Date: Tue, 5 Jul 2016 12:59:42 +0200 MIME-Version: 1.0 In-Reply-To: <20160705130015-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 0/6] x86: Physical address limit patches List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , "Dr. David Alan Gilbert" Cc: marcel@redhat.com, kraxel@redhat.com, qemu-devel@nongnu.org, ehabkost@redhat.com On 05/07/2016 12:06, Michael S. Tsirkin wrote: > > -m 2G,slots=16,maxmem=2T > > > > On a host with a 39bit physaddress limit do you error > > on that or not? I think oVirt is currently doing something > > similar to that, but I'm trying to get confirmation. > > That would only be a problem since pci is allocated above > maxmem so 64 bit pci addresses aren't accessible. > With my proposal we can actually force firmware to avoid > using 64 bit memory for that config. > Will work better than today. So you would remove completely the 64-bit _CRS in this case? How do you handle migration in the above scenario from say 46bit host to 39bit host, where the firmware has mapped (while running on the source) a 64-bit BAR above the destination's maximum physical address? Thanks, Paolo