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 <imamm...@redhat.com> --- CC: isaku.yamah...@intel.com CC: m...@redhat.com CC: rein...@netbsd.org CC: isaku.yamah...@gmail.com CC: berra...@redhat.com CC: pbonz...@redhat.com CC: f4...@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