[PULL 6/9] acpi/piix4: reinitialize acpi PM device on reset

["Michael S. Tsirkin" <mst@redhat.com>]

From: Isaku Yamahata <isaku.yamahata@intel.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.

Occasionally this patch adds reset acpi PM related registers on
piix4 reset time and de-assert sci.
piix4_pm_realize() initializes acpi pm tmr, evt, cnt and gpe.
Reset them on device reset. pm_reset() in ich9.c correctly calls
corresponding reset functions.

Fixes: 6be8cf56bc8b (acpi/core: always set SCI_EN when SMM isn't supported)
Reported-by: Reinoud Zandijk <reinoud@NetBSD.org>
Co-developed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Message-Id: <8a5bbd19727045ec863523830078dd4ca63f6a9a.1616532563.git.isaku.yamahata@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/acpi/piix4.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index 6056d51667..8f8b0e95e5 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -326,6 +326,13 @@ static void piix4_pm_reset(DeviceState *dev)
         /* Mark SMM as already inited (until KVM supports SMM). */
         pci_conf[0x5B] = 0x02;
     }
+
+    acpi_pm1_evt_reset(&s->ar);
+    acpi_pm1_cnt_reset(&s->ar);
+    acpi_pm_tmr_reset(&s->ar);
+    acpi_gpe_reset(&s->ar);
+    acpi_update_sci(&s->ar, s->irq);
+
     pm_io_space_update(s);
     acpi_pcihp_reset(&s->acpi_pci_hotplug, !s->use_acpi_root_pci_hotplug);
 }
-- 
MST