Re: [PATCH for-6.0] x86:acpi:piix4: reinitialize PM1.CNT on reset

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 16 Mar 2021 13:56:03 -0700
Isaku Yamahata <isaku.yamahata@gmail.com> wrote:

> The fix itself looks good to me for the reported issue.
> Should more registers be reset in theory?
> But it would cause other issues.
> 
> i.e.
> acpi_pm1_evt_reset(&s->ar);
> acpi_pm_tmr_reset(&s->ar);
> acpi_gpe_reset(&s->ar);

It's very possible we should reset other registers too.
Can you look into it, please?

> 
> Reviewed-by: Isaku Yamahata <isaku.yamahata@intel.com>

Thanks!

> 
> Thanks,
> 
> 
> On Tue, Mar 16, 2021 at 04:29:56PM -0400,
> Igor Mammedov <imammedo@redhat.com> wrote:
> 
> > Commit 6be8cf56bc8b made sure that SCI is enabled in PM1.CNT
> > on reset in acpi_only mode by modifying acpi_pm1_cnt_reset() and
> > that worked for q35 as expected.
> > 
> > The function was introduced by commit
> >   eaba51c573a (acpi, acpi_piix, vt82c686: factor out PM1_CNT logic)
> > that forgot to actually call it at piix4 reset time and as result
> > SCI_EN wasn't set as was expected by 6be8cf56bc8b in acpi_only mode.
> > 
> > So Windows crashes when it notices that SCI_EN is not set and FADT is
> > not providing information about how to enable it anymore.
> > Reproducer:
> >    qemu-system-x86_64 -enable-kvm -M pc-i440fx-6.0,smm=off -cdrom any_windows_10x64.iso
> > 
> > Fix it by calling acpi_pm1_cnt_reset() at piix4 reset time.
> > 
> > Fixes: 6be8cf56bc8b (acpi/core: always set SCI_EN when SMM isn't supported)
> > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> > ---
> > CC: isaku.yamahata@intel.com
> > CC: mst@redhat.com
> > CC: reinoud@NetBSD.org
> > CC: isaku.yamahata@gmail.com
> > CC: berrange@redhat.com
> > CC: pbonzini@redhat.com
> > CC: f4bug@amsat.org
> > ---
> >  hw/acpi/piix4.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> > index 1efc0ded9f..7cab438015 100644
> > --- a/hw/acpi/piix4.c
> > +++ b/hw/acpi/piix4.c
> > @@ -325,6 +325,7 @@ static void piix4_pm_reset(DeviceState *dev)
> >          /* Mark SMM as already inited (until KVM supports SMM). */
> >          pci_conf[0x5B] = 0x02;
> >      }
> > +    acpi_pm1_cnt_reset(&s->ar);
> >      pm_io_space_update(s);
> >      acpi_pcihp_reset(&s->acpi_pci_hotplug, !s->use_acpi_root_pci_hotplug);
> >  }
> > -- 
> > 2.27.0
> > 
> >   
>