[Qemu-devel] [PULL 6/7] pc: memhotplug: keep reserved-memory-end broken on 2.4 and earlier machines

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

From: Igor Mammedov <imammedo@redhat.com>

it will prevent guests on old machines from seeing
inconsistent memory mapping in firmware/ACPI views.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
---
 include/hw/i386/pc.h | 1 +
 hw/i386/pc.c         | 8 ++++++--
 hw/i386/pc_piix.c    | 2 ++
 hw/i386/pc_q35.c     | 2 ++
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/hw/i386/pc.h b/include/hw/i386/pc.h
index d0cad87..ff0b48b 100644
--- a/include/hw/i386/pc.h
+++ b/include/hw/i386/pc.h
@@ -59,6 +59,7 @@ struct PCMachineClass {
     MachineClass parent_class;
 
     /*< public >*/
+    bool broken_reserved_end;
     HotplugHandler *(*get_hotplug_handler)(MachineState *machine,
                                            DeviceState *dev);
 };
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 354e1b3..b5107f7 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1412,8 +1412,12 @@ FWCfgState *pc_memory_init(PCMachineState *pcms,
 
     if (guest_info->has_reserved_memory && pcms->hotplug_memory.base) {
         uint64_t *val = g_malloc(sizeof(*val));
-        uint64_t res_mem_end = pcms->hotplug_memory.base +
-                               memory_region_size(&pcms->hotplug_memory.mr);
+        PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
+        uint64_t res_mem_end = pcms->hotplug_memory.base;
+
+        if (!pcmc->broken_reserved_end) {
+            res_mem_end += memory_region_size(&pcms->hotplug_memory.mr);
+        }
         *val = cpu_to_le64(ROUND_UP(res_mem_end, 0x1ULL << 30));
         fw_cfg_add_file(fw_cfg, "etc/reserved-memory-end", val, sizeof(*val));
     }
diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 117f8dc..eab39fc 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -449,7 +449,9 @@ static void pc_i440fx_machine_options(MachineClass *m)
 
 static void pc_i440fx_2_4_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_i440fx_machine_options(m);
+    pcmc->broken_reserved_end = true;
     m->default_machine_opts = "firmware=bios-256k.bin";
     m->default_display = "std";
     m->alias = "pc";
diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index 4b38dee..11601ab 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -368,7 +368,9 @@ static void pc_q35_machine_options(MachineClass *m)
 
 static void pc_q35_2_4_machine_options(MachineClass *m)
 {
+    PCMachineClass *pcmc = PC_MACHINE_CLASS(m);
     pc_q35_machine_options(m);
+    pcmc->broken_reserved_end = true;
     m->default_machine_opts = "firmware=bios-256k.bin";
     m->default_display = "std";
     m->no_floppy = 1;
-- 
MST