Re: [Qemu-devel] [PATCH] hw/acpi: fix Q35 support for legacy Windows OS

[Marcel Apfelbaum]

On 03/07/2016 02:36 PM, Michael S. Tsirkin wrote:
> On Mon, Mar 07, 2016 at 01:06:43PM +0100, Igor Mammedov wrote:
> > On Sun,  6 Mar 2016 14:17:56 +0200
> > Marcel Apfelbaum <address@hidden> wrote:
> >
> > > Legacy Windows operating systems like Windows XP and Windows 2003
> > > require _DIS method to be present for all interrupt links.
> > >
> > > PC machines already have a no-op implemented for GSI links, add
> > > it also in Q35.
> > Maybe I don't see but only LINKS has no-op _DIS, the rest of
> > links have _DIS that does something. According to spec
> > _STA must return disabled status after _DIS has been called.
>
> A no-op _DIS is OK as long as the interrupt can not be disabled.
> Marcel, how about a comment explaining this?

Sure, I'll add a comment and re-post.

> BTW, going over it again:
> - we really need to set separate UIDs for them, might
>    be a good idea to fix that, might it not?

Absolutely (in my opinion), Igor is OK if I'll submit a patch for it?
Since we're getting rid of old Q35 machines we don't care about compatibility 
here.

> -
>      method = aml_method("_SRS", 1, AML_NOTSERIALIZED);
>      aml_append(method, aml_create_dword_field(aml_arg(0), aml_int(5), "PRRI"));
>      aml_append(method, aml_store(aml_name("PRRI"), reg));
>      aml_append(dev, method);
>
> should this be serialized as it creates a local name (PRRI)?

I'll let Igor answer this.

Thanks,
Marcel

> > > Signed-off-by: Marcel Apfelbaum <address@hidden>
> > > ---
> > >
> > > Hi,
> > >
> > > I tested this patch with WinXP and Win 2003, but also with Win 10, and Fedora.
> > > This solves a BSOD early in the setup process.
> > >
> > > WinXP/2003 can be tested using:
> > >       -device piix3-ide,id=legacyide \
> > >       -drive file=winxp-q35.qcow2,if=none,id=disk -device 
> > > ide-hd,drive=disk,bus=legacyide.0 \
> > >       -drive file=xp_sp3.iso,if=none,id=cdrom -device 
> > > ide-cd,drive=cdrom,bus=legacyide.1
> > >
> > > Please note that you have to use the piix3-ide because Win2003 (and probably XP)
> > > does not have Q35 AHCI drivers inbox.
> > >
> > > Thanks,
> > > Marcel
> > >
> > >   hw/i386/acpi-build.c | 3 +++
> > >   1 file changed, 3 insertions(+)
> > >
> > > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > > index 52c9470..4c66568 100644
> > > --- a/hw/i386/acpi-build.c
> > > +++ b/hw/i386/acpi-build.c
> > > @@ -1509,6 +1509,9 @@ static Aml *build_gsi_link_dev(const char *name, uint8_t 
> > > uid, uint8_t gsi)
> > >
> > >       aml_append(dev, aml_name_decl("_CRS", crs));
> > >
> > > +    method = aml_method("_DIS", 0, AML_NOTSERIALIZED);
> > > +    aml_append(dev, method);
> > > +
> > >       method = aml_method("_SRS", 1, AML_NOTSERIALIZED);
> > >       aml_append(dev, method);