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

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 7 Mar 2016 15:21:44 +0200
Marcel Apfelbaum <marcel@redhat.com> wrote:

> 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 <marcel@redhat.com> 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.
Sure, provided Windows doesn't complain/crash.

> 
> > -
> >      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'd make it serialize for other reason,
it shouldn't happen but what if method were executed in parallel

> >  
> 
> I'll let Igor answer this.
> 
> Thanks,
> Marcel
> 
> >>  
> >>>
> >>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> >>> ---
> >>>
> >>> 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);
> >>>  
>