[Qemu-devel] [PATCH 2/2] pc: memhotplug: keep reserved-memory-end broken on 2.4 and earlier machines

[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>
---
PS: this patch probably clashes with Eduardo's
    pc_compat refactoring, so I've split it from
    main fix, if applied via Eduardo's it could
    be squashed in main fix after merging on top
    of his patches or as is if goes in first.
---
 hw/i386/pc.c         | 8 ++++++--
 hw/i386/pc_piix.c    | 2 ++
 hw/i386/pc_q35.c     | 2 ++
 include/hw/i386/pc.h | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

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 b82921d..589f530 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -451,7 +451,9 @@ 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 7217cbf..839d3b9 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -370,7 +370,9 @@ 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;
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);
 };
-- 
1.8.3.1