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

[Igor Mammedov <imammedo@redhat.com>]

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