On Wed, 26 Jul 2017 15:33:37 +0200 Paolo Bonzini <pbonz...@redhat.com> wrote:
> On 26/07/2017 15:30, Igor Mammedov wrote: > > On Wed, 26 Jul 2017 15:10:40 +0200 > > Paolo Bonzini <pbonz...@redhat.com> wrote: > > > >> On 26/07/2017 15:08, Igor Mammedov wrote: > >>> On Tue, 25 Jul 2017 18:23:22 +0200 > >>> Paolo Bonzini <pbonz...@redhat.com> 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. :) Even though I'd prefer to tie revision switch to machine type+version, and kill rev1 support along with machine type when it's removed v1, https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg06822.html, there were objections to it and Michael suggested to use just rev1 for PC based machine types and rev3 for Q35 based machine types. > 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. > >>>> > >>> > >> > > >
