hw/acpi: move "etc/system-states" fw_cfg file from PIIX4 to core

The acpi_pm1_cnt_init() core function is responsible for setting up the
register block that will ultimately react to S3 and S4 requests (see
acpi_pm1_cnt_write()). It makes sense to advertise this configuration to
the guest firmware via an easy to parse fw_cfg file (ACPI is too complex
for firmware to parse), and indeed PIIX4 does that. However, since
acpi_pm1_cnt_init() is not specific to PIIX4, neither should be the fw_cfg
file.

This patch makes "etc/system-states" appear on all chipsets modified in
the previous patch, not just PIIX4 (assuming they have fw_cfg at all).

RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1204696
Cc: Amit Shah <amit.shah@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Aurelien Jarno <aurelien@aurel32.net>
Cc: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: NLaszlo Ersek <lersek@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NLaszlo Ersek <lersek@redhat.com>

hw/acpi/core.c

@@ -22,6 +22,7 @@
 #include "hw/hw.h"
 #include "hw/i386/pc.h"
 #include "hw/acpi/acpi.h"
+#include "hw/nvram/fw_cfg.h"
 #include "qemu/config-file.h"
 #include "qapi/opts-visitor.h"
 #include "qapi/dealloc-visitor.h"
@@ -595,12 +596,23 @@ static const MemoryRegionOps acpi_pm_cnt_ops = {
 void acpi_pm1_cnt_init(ACPIREGS *ar, MemoryRegion *parent,
                        bool disable_s3, bool disable_s4, uint8_t s4_val)
 {
+    FWCfgState *fw_cfg;
+
     ar->pm1.cnt.s4_val = s4_val;
     ar->wakeup.notify = acpi_notify_wakeup;
     qemu_register_wakeup_notifier(&ar->wakeup);
     memory_region_init_io(&ar->pm1.cnt.io, memory_region_owner(parent),
                           &acpi_pm_cnt_ops, ar, "acpi-cnt", 2);
     memory_region_add_subregion(parent, 4, &ar->pm1.cnt.io);
+
+    fw_cfg = fw_cfg_find();
+    if (fw_cfg) {
+        uint8_t suspend[6] = {128, 0, 0, 129, 128, 128};
+        suspend[3] = 1 | ((!disable_s3) << 7);
+        suspend[4] = s4_val | ((!disable_s4) << 7);
+
+        fw_cfg_add_file(fw_cfg, "etc/system-states", g_memdup(suspend, 6), 6);
+    }
 }
 
 void acpi_pm1_cnt_reset(ACPIREGS *ar)

hw/acpi/piix4.c

@@ -525,14 +525,6 @@ I2CBus *piix4_pm_init(PCIBus *bus, int devfn, uint32_t smb_io_base,
 
     qdev_init_nofail(dev);
 
-    if (fw_cfg) {
-        uint8_t suspend[6] = {128, 0, 0, 129, 128, 128};
-        suspend[3] = 1 | ((!s->disable_s3) << 7);
-        suspend[4] = s->s4_val | ((!s->disable_s4) << 7);
-
-        fw_cfg_add_file(fw_cfg, "etc/system-states", g_memdup(suspend, 6), 6);
-    }
-
     return s->smb.smbus;
 }