Re: [Qemu-devel] Commit 77af8a2b95b79699de650965d5228772743efe84 breaks Windows 2000 support

[Igor Mammedov]

On Thu, 20 Jul 2017 21:29:33 +0200
Phil Dennis-Jordan <address@hidden> wrote:

> On Thu, Jul 20, 2017 at 6:40 PM, Programmingkid
> <address@hidden> wrote:
> > I noticed that Windows 2000 does not boot up in QEMU recently. After 
> > bisecting the issue I found the offending commit:
w2k is very ancient (and long time EOLed), I can't even download it from msdn 
to test
(oldest available is XP)

do we really care about it?

 
> Ouch. I reckon we have 2 options for fixing this:
> 
> 1. Export two FADTs, one ACPI 1.0, one ACPI 2.0. The latter would need
> to be pointed to by an XSDT, which Qemu currently doesn't implement at
> all as far as I'm aware. Any ideas on how SeaBIOS or OVMF would handle
> this? Any likely other OS regressions?
> 
> 2. Select FADT version with an option. This one is definitely safe,
> but adds yet another option.
the 3rd simpler option is:
  force rev1 on old machine types (2.9 and older),
  using machine compat machinery and use rev3 on newer machines


> 
> Thoughts?
> 
> 
> > commit 77af8a2b95b79699de650965d5228772743efe84
> > Author: Phil Dennis-Jordan <address@hidden>
> > Date:   Wed Mar 15 19:20:26 2017 +1300
> >
> >     hw/i386: Use Rev3 FADT (ACPI 2.0) instead of Rev1 to improve guest OS 
> > support.
> >
> >     This updates the FADT generated for x86/64 machine types from Revision 
> > 1 to 3. (Based on ACPI standard 2.0 instead of 1.0) The intention is to 
> > expose the reset register information to guest operating systems which 
> > require it, specifically OS X/macOS. Revision 1 FADTs do not contain the 
> > fields relating to the reset register.
> >
> >     The new layout and contents remains backwards-compatible with operating 
> > systems which only support ACPI 1.0, as the existing fields are not 
> > modified by this change, as the 64-bit and 32-bit variants are allowed to 
> > co-exist according to the ACPI 2.0 standard. No regressions became apparent 
> > in tests with a range of Windows (XP-10) and Linux versions.
> >
> >     The BIOS tables test suite's FADT checksum test has also been updated 
> > to reflect the new FADT layout and content.
> >
> >     Signed-off-by: Phil Dennis-Jordan <address@hidden>
> >     Message-Id: <address@hidden>
> >     Signed-off-by: Paolo Bonzini <address@hidden>
> >
> > :040000 040000 40063761c0b86f87e798e03ea48eff9ea0753425 
> > 6d2a94150cf1eafb16f0ccf6325281415fef64a6 M      hw
> > :040000 040000 fe3f1480a91b76fea238c765f0725e715932d96d 
> > 68f9368d8d78fd3267f609b603f97e8a74bdf528 M      include
> > :040000 040000 895e961b0a160100aa95b2f557cfe6b87a7d9bff 
> > 8ed08cef10fddee7814e38ad62be11371592a75a M      tests
> >
> >  
>