From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58989) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1daMRv-0004G7-06 for qemu-devel@nongnu.org; Wed, 26 Jul 2017 09:34:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1daMRq-000450-OG for qemu-devel@nongnu.org; Wed, 26 Jul 2017 09:34:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37806) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1daMRq-00043a-FY for qemu-devel@nongnu.org; Wed, 26 Jul 2017 09:33:58 -0400 References: <3E24AFDE-D25A-416B-A600-3C2221C3A9F1@gmail.com> <20170721110636.19412e6c@nial.brq.redhat.com> <20170721092338.GE17693@redhat.com> <20170721143432.0e888800@nial.brq.redhat.com> <9767baed-582d-8aab-f9a6-0d04d7ec9d23@redhat.com> <165445ef-c2fb-f49e-8185-2a8af0e27bf2@redhat.com> <20170726150810.3a48d5f0@nial.brq.redhat.com> <95a701f0-c693-e1f7-be52-36f05bfc856a@redhat.com> <20170726153020.4c20b279@nial.brq.redhat.com> From: Paolo Bonzini Message-ID: <83edcc44-62ff-ff53-371d-efb4c0d10259@redhat.com> Date: Wed, 26 Jul 2017 15:33:37 +0200 MIME-Version: 1.0 In-Reply-To: <20170726153020.4c20b279@nial.brq.redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] Commit 77af8a2b95b79699de650965d5228772743efe84 breaks Windows 2000 support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: Laszlo Ersek , Phil Dennis-Jordan , "Daniel P. Berrange" , Phil Dennis-Jordan , ehabkost@redhat.com, "qemu-devel@nongnu.org qemu-devel" , Programmingkid , Richard Henderson , "Michael S. Tsirkin" On 26/07/2017 15:30, Igor Mammedov wrote: > On Wed, 26 Jul 2017 15:10:40 +0200 > Paolo Bonzini wrote: > >> On 26/07/2017 15:08, Igor Mammedov wrote: >>> On Tue, 25 Jul 2017 18:23:22 +0200 >>> Paolo Bonzini wrote: >>> >>>> On 25/07/2017 18:14, Laszlo Ersek wrote: >>>>> "No regressions became apparent in tests with a range of Windows >>>>> (XP-10)" >>>>> >>>>> In theory, w2k falls within that range. >>>> >>>> Nope, Windows 2000 is like NT 5.0, XP is like NT 5.1. :( >>>> >>>> One possibility is to fix it in SeaBIOS instead: if you get a 2.0 FADT >>>> and an XSDT and no RSDT, it can build an RSDT and a 1.0 FADT itself, >>>> patching the RSDT to point to it. >>>> >>>> It's a hack, but it's the only place I see to make it "just work". And >>>> it could be extended nicely in the future. >>>> >>>> All QEMU would have to do is to provide an XSDT _instead_ of an RSDT. >>> I'd support it, however it would break migrated guests with old BIOS >>> image in RAM on reboot. >> >> Why? Shouldn't the old ACPI tables get migrated together with the old >> BIOS? Or are they rebuilt after reset? > they are rebuild on reset, but I've been wrong Hmm so we need this plus keeping old machine types fixed to rev1 and RSDT. Diffstat will get worse. :) Paolo > Looking at SeaBIOS something similar to your suggestion also should work, > if > RsdpAddr = find_acpi_rsdp(); > fails, current SeaBIOS falls back to its own ACPI tables. > > but it seems that we don't even need to go to that extent, > all user have to do is to use "-no-acpi" CLI option with QEMU > for any SeaBIOS to fallback to embedded legacy ACPI tables. > > Maybe we should just fix wiki > http://wiki.qemu.org/Windows2000 > to recommend using '-no-acpi' option when running w2k and > leave PC machine at rev3 and mention it in release notes. > > Opinions? > >> Paolo >> >>> Legacy users have an option to build SeaBIOS without ACPI from QEMU >>> support by turning off CONFIG_FW_ROMFILE_LOAD (or use old SeaBIOS) >>> which leads to using legacy tables included in SeaBIOS. >>> Then mgmt layer above libvirt which knows what guest OS it's >>> going to run can pick legacy BIOS image for it. >>> >>> But the testing issue will still stay as normally it's not tested >>> path. >>> >>> PS: >>> For now we are going to revert PC machine to rev1 and leave q35 at rev3 >>> as Michael suggested to keep both w2k and macos happy. >>> >>>> >>>> Paolo >>>> >>>>> In practice, it is impossible to >>>>> test *all* Windows versions against ACPI generator changes, even if you >>>>> try to be thorough (which Phil was). One might not even *know about* >>>>> "all" Windows versions. So people using w2k and similar should >>>>> co-maintain the ACPI stuff and report back with testing on the fly; >>>>> otherwise regressions are impossible to avoid. >>>> >>> >> >