From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58511) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VUboQ-0005qw-MF for qemu-devel@nongnu.org; Fri, 11 Oct 2013 08:27:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VUboM-0004pK-8h for qemu-devel@nongnu.org; Fri, 11 Oct 2013 08:27:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36308) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VUboM-0004oE-1O for qemu-devel@nongnu.org; Fri, 11 Oct 2013 08:27:18 -0400 Message-ID: <1381494432.23065.7.camel@nilsson.home.kraxel.org> From: Gerd Hoffmann Date: Fri, 11 Oct 2013 14:27:12 +0200 In-Reply-To: <20131011132006.7261acd8@nial.usersys.redhat.com> References: <1381409669-8044-1-git-send-email-kraxel@redhat.com> <20131011132006.7261acd8@nial.usersys.redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RfC PATCH] e820: pass high memory too. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: Andrea Arcangeli , qemu-devel@nongnu.org, Anthony Liguori On Fr, 2013-10-11 at 13:20 +0200, Igor Mammedov wrote: > On Thu, 10 Oct 2013 14:54:29 +0200 > Gerd Hoffmann wrote: > > > We have a fw_cfg entry to pass e820 entries from qemu to the firmware. > > Today it's used to pass reservations only. This patch makes qemu pass > > entries for RAM too. > > > > This allows to pass RAM sizes larger than 1TB to the firmware and it > > will also allow to pass non-contignous memory ramges should we decide > > to implement that some day, say for our virtual numa nodes. > > > > Obviously this needs some extra care to not break existing firware. > > > > SeaBIOS loads the entries and happily adds them without looking at the > > type. Which is problematic for memory below 4g as this will overwrite > > reservations added for bios memory etc. For memory above 4g it works > > just fine, seabios will merge the entry derived from cmos with the one > > loaded from fw_cfg. > It will make amount of available memory in e820 table more than described > in smbios and could break MS's SMBIOS HCT test. Happens only in case the installed amount of memory is larger than 1TB (which is the maximum the cmos can describe). Such a setup doesn't work correctly without the patch anyway, so it isn't a regression IMHO. And with an additional patch on the seabios side we can fix the smbios info even for the >1TB case. > Perhaps related smbios info > also should be picked up from QEMU. Worth investigating, but lets concentrate on the acpi table merge first. cheers, Gerd