From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56092) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cqxxh-0000Yo-TM for qemu-devel@nongnu.org; Thu, 23 Mar 2017 04:19:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cqxxe-00075b-Q3 for qemu-devel@nongnu.org; Thu, 23 Mar 2017 04:19:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54126) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cqxxe-000751-Jp for qemu-devel@nongnu.org; Thu, 23 Mar 2017 04:19:10 -0400 Message-ID: <1490257145.463.24.camel@redhat.com> From: Gerd Hoffmann Date: Thu, 23 Mar 2017 09:19:05 +0100 In-Reply-To: References: <87bmstu19t.fsf@dusky.pond.sub.org> <1f744cad-f67b-92d3-b4e4-32f8b05c643c@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Subject: Re: [Qemu-devel] Minimum RAM size for PC machines? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Hildenbrand Cc: Thomas Huth , Markus Armbruster , qemu-devel@nongnu.org, Peter Maydell , seabios@seabios.org, =?ISO-8859-1?Q?L=E1szl=F3_=C9rsek?= On Mi, 2017-03-22 at 11:19 +0100, David Hildenbrand wrote: > On 22.03.2017 11:03, Thomas Huth wrote: > > On 22.03.2017 10:08, Markus Armbruster wrote: > > [...] > >> Are we now ready to accept a simple & stupid patch that actually helps > >> users, say letting boards that care declare minimum and maximum RAM > >> size? And make PC reject RAM size less than 1MiB, even though "someon= e" > >> might conceivably have firmware that works with less? > >=20 > > I'd say enforce a minimum RAM size on the normal "pc" and "q35" machine= , > > but still allow smaller sizes on the "isapc" machine. So if "someone" > > comes around and claims to have a legacy firmware that wants less memor= y > > than 1MiB, just point them to the isapc machine. > > Just my 0.02 =E2=82=AC. > >=20 > > Thomas >=20 > Or maybe simply warn the user that things may go wrong instead of > enforcing it. Why bother? I have my doubts physical i440fx works with less than 1M either, given that this memory is needed to shadow the roms. Possibly you can't even find dimms that are small to plug them into such a system to try ... I'd say just add a hard limit and be done with it. Maybe exclude isapc. That one hasn't shadow support so things have at least a chance to work with less than 1M of memory. But honestly I'd rather drop isapc, together with ia64 and sparc. I mean, what is the use case? 'pc' machine type is compatible enough with vga and ide ports being on the standard isa locations so even msdos which has no pci support at all boots happily. cheers, Gerd