From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49210) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cqytE-0003p0-Dq for qemu-devel@nongnu.org; Thu, 23 Mar 2017 05:18:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cqyt9-0004oc-FQ for qemu-devel@nongnu.org; Thu, 23 Mar 2017 05:18:40 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35480) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cqyt9-0004o5-93 for qemu-devel@nongnu.org; Thu, 23 Mar 2017 05:18:35 -0400 References: <87bmstu19t.fsf@dusky.pond.sub.org> <1f744cad-f67b-92d3-b4e4-32f8b05c643c@redhat.com> <1490257145.463.24.camel@redhat.com> From: David Hildenbrand Message-ID: Date: Thu, 23 Mar 2017 10:18:28 +0100 MIME-Version: 1.0 In-Reply-To: <1490257145.463.24.camel@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] Minimum RAM size for PC machines? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: Thomas Huth , Markus Armbruster , qemu-devel@nongnu.org, Peter Maydell , seabios@seabios.org, =?UTF-8?B?TMOhc3psw7Mgw4lyc2Vr?= On 23.03.2017 09:19, Gerd Hoffmann wrote: > 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 hel= ps >>>> users, say letting boards that care declare minimum and maximum RAM >>>> size? And make PC reject RAM size less than 1MiB, even though "some= one" >>>> might conceivably have firmware that works with less? >>> >>> I'd say enforce a minimum RAM size on the normal "pc" and "q35" machi= ne, >>> but still allow smaller sizes on the "isapc" machine. So if "someone" >>> comes around and claims to have a legacy firmware that wants less mem= ory >>> than 1MiB, just point them to the isapc machine. >>> Just my 0.02 =E2=82=AC. >>> >>> Thomas >> >> Or maybe simply warn the user that things may go wrong instead of >> enforcing it. >=20 > 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 syste= m > to try ... Because it seems to work if you supply the correct rom. We are trying to catch user errors, don't we? >=20 > I'd say just add a hard limit and be done with it. "640K ought to be enough for anybody". Any limit we set will become out of date. >=20 > 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 port= s > being on the standard isa locations so even msdos which has no pci > support at all boots happily. I think I like that idea. > cheers, > Gerd >=20 --=20 Thanks, David