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.yamah...@intel.com> Thanks, On Tue, Mar 16, 2021 at 04:29:56PM -0400, Igor Mammedov <imamm...@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 <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 > > -- Isaku Yamahata <isaku.yamah...@gmail.com>