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

[Isaku Yamahata]

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);

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

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
> 
> 

-- 
Isaku Yamahata <isaku.yamahata@gmail.com>