acpi: add hardware implementation for memory hot unplug

- implements QEMU hardware part of memory hot unplug protocol
  described at "docs/spec/acpi_mem_hotplug.txt"
- handles memory remove notification event
- handles device eject notification

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

docs/specs/acpi_mem_hotplug.txt

@@ -19,7 +19,9 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
               1: Device insert event, used to distinguish device for which
                  no device check event to OSPM was issued.
                  It's valid only when bit 1 is set.
-              2-7: reserved and should be ignored by OSPM
+              2: Device remove event, used to distinguish device for which
+                 no device eject request to OSPM was issued.
+              3-7: reserved and should be ignored by OSPM
       [0x15-0x17] reserved
 
   write access:
@@ -38,7 +40,12 @@ Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
               1: if set to 1 clears device insert event, set by OSPM
                  after it has emitted device check event for the
                  selected memory device
-              2-7: reserved, OSPM must clear them before writing to register
+              2: if set to 1 clears device remove event, set by OSPM
+                 after it has emitted device eject request for the
+                 selected memory device
+              3: if set to 1 initiates device eject, set by OSPM when it
+                 triggers memory device removal and calls _EJ0 method
+              4-7: reserved, OSPM must clear them before writing to register
 
 Selecting memory device slot beyond present range has no effect on platform:
    - write accesses to memory hot-plug registers not documented above are

hw/acpi/memory_hotplug.c

@@ -2,6 +2,7 @@
 #include "hw/acpi/pc-hotplug.h"
 #include "hw/mem/pc-dimm.h"
 #include "hw/boards.h"
+#include "hw/qdev-core.h"
 #include "trace.h"
 #include "qapi-event.h"
 
@@ -91,6 +92,8 @@ static void acpi_memory_hotplug_write(void *opaque, hwaddr addr, uint64_t data,
     MemHotplugState *mem_st = opaque;
     MemStatus *mdev;
     ACPIOSTInfo *info;
+    DeviceState *dev = NULL;
+    HotplugHandler *hotplug_ctrl = NULL;
 
     if (!mem_st->dev_count) {
         return;
@@ -128,13 +131,29 @@ static void acpi_memory_hotplug_write(void *opaque, hwaddr addr, uint64_t data,
         qapi_event_send_acpi_device_ost(info, &error_abort);
         qapi_free_ACPIOSTInfo(info);
         break;
-    case 0x14:
+    case 0x14: /* set is_* fields  */
         mdev = &mem_st->devs[mem_st->selector];
         if (data & 2) { /* clear insert event */
             mdev->is_inserting  = false;
             trace_mhp_acpi_clear_insert_evt(mem_st->selector);
+        } else if (data & 4) {
+            mdev->is_removing = false;
+            trace_mhp_acpi_clear_remove_evt(mem_st->selector);
+        } else if (data & 8) {
+            if (!mdev->is_enabled) {
+                trace_mhp_acpi_ejecting_invalid_slot(mem_st->selector);
+                break;
+            }
+
+            dev = DEVICE(mdev->dimm);
+            hotplug_ctrl = qdev_get_hotplug_handler(dev);
+            /* call pc-dimm unplug cb */
+            hotplug_handler_unplug(hotplug_ctrl, dev, NULL);
+            trace_mhp_acpi_pc_dimm_deleted(mem_st->selector);
         }
         break;
+    default:
+        break;
     }
 
 }

hw/core/qdev.c

@@ -273,7 +273,7 @@ void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id,
     dev->alias_required_for_version = required_for_version;
 }
 
-static HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev)
+HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev)
 {
     HotplugHandler *hotplug_ctrl = NULL;
 

hw/i386/acpi-build.c

@@ -879,6 +879,12 @@ build_ssdt(GArray *table_data, GArray *linker,
         aml_append(field,
             /*(read) 1 if has a insert event. (write) 1 to clear event */
             aml_named_field(stringify(MEMORY_SLOT_INSERT_EVENT), 1));
+        aml_append(field,
+            /* (read) 1 if has a remove event. (write) 1 to clear event */
+            aml_named_field(stringify(MEMORY_SLOT_REMOVE_EVENT), 1));
+        aml_append(field,
+            /* initiates device eject, write only */
+            aml_named_field(stringify(MEMORY_SLOT_EJECT), 1));
         aml_append(scope, field);
 
         field = aml_field(stringify(MEMORY_HOTPLUG_IO_REGION), aml_dword_acc,
@@ -923,6 +929,12 @@ build_ssdt(GArray *table_data, GArray *linker,
             )));
             aml_append(dev, method);
 
+            method = aml_method("_EJ0", 1);
+            s = BASEPATH stringify(MEMORY_SLOT_EJECT_METHOD);
+            aml_append(method, aml_return(aml_call2(
+                       s, aml_name("_UID"), aml_arg(0))));
+            aml_append(dev, method);
+
             aml_append(sb_scope, dev);
         }
 

hw/i386/acpi-dsdt-mem-hotplug.dsl

@@ -29,6 +29,8 @@
             External(MEMORY_SLOT_PROXIMITY, FieldUnitObj) // read only
             External(MEMORY_SLOT_ENABLED, FieldUnitObj) // 1 if enabled, read only
             External(MEMORY_SLOT_INSERT_EVENT, FieldUnitObj) // (read) 1 if has a insert event. (write) 1 to clear event
+            External(MEMORY_SLOT_REMOVE_EVENT, FieldUnitObj) // (read) 1 if has a remove event. (write) 1 to clear event
+            External(MEMORY_SLOT_EJECT, FieldUnitObj) // initiates device eject, write only
             External(MEMORY_SLOT_SLECTOR, FieldUnitObj) // DIMM selector, write only
             External(MEMORY_SLOT_OST_EVENT, FieldUnitObj) // _OST event code, write only
             External(MEMORY_SLOT_OST_STATUS, FieldUnitObj) // _OST status code, write only
@@ -55,8 +57,10 @@
                     If (LEqual(MEMORY_SLOT_INSERT_EVENT, One)) { // Memory device needs check
                         MEMORY_SLOT_NOTIFY_METHOD(Local0, 1)
                         Store(1, MEMORY_SLOT_INSERT_EVENT)
+                    } Elseif (LEqual(MEMORY_SLOT_REMOVE_EVENT, One)) { // Ejection request
+                        MEMORY_SLOT_NOTIFY_METHOD(Local0, 3)
+                        Store(1, MEMORY_SLOT_REMOVE_EVENT)
                     }
-                    // TODO: handle memory eject request
                     Add(Local0, One, Local0) // goto next DIMM
                 }
                 Release(MEMORY_SLOT_LOCK)
@@ -156,5 +160,12 @@
                 Store(Arg2, MEMORY_SLOT_OST_STATUS)
                 Release(MEMORY_SLOT_LOCK)
             }
+
+            Method(MEMORY_SLOT_EJECT_METHOD, 2) {
+                Acquire(MEMORY_SLOT_LOCK, 0xFFFF)
+                Store(ToInteger(Arg0), MEMORY_SLOT_SLECTOR) // select DIMM
+                Store(1, MEMORY_SLOT_EJECT)
+                Release(MEMORY_SLOT_LOCK)
+            }
         } // Device()
     } // Scope()

include/hw/acpi/pc-hotplug.h

@@ -43,6 +43,8 @@
 #define MEMORY_SLOT_PROXIMITY        MPX
 #define MEMORY_SLOT_ENABLED          MES
 #define MEMORY_SLOT_INSERT_EVENT     MINS
+#define MEMORY_SLOT_REMOVE_EVENT     MRMV
+#define MEMORY_SLOT_EJECT            MEJ
 #define MEMORY_SLOT_SLECTOR          MSEL
 #define MEMORY_SLOT_OST_EVENT        MOEV
 #define MEMORY_SLOT_OST_STATUS       MOSC
@@ -51,6 +53,7 @@
 #define MEMORY_SLOT_CRS_METHOD       MCRS
 #define MEMORY_SLOT_OST_METHOD       MOST
 #define MEMORY_SLOT_PROXIMITY_METHOD MPXM
+#define MEMORY_SLOT_EJECT_METHOD     MEJ0
 #define MEMORY_SLOT_NOTIFY_METHOD    MTFY
 #define MEMORY_SLOT_SCAN_METHOD      MSCN
 

include/hw/qdev-core.h

@@ -266,6 +266,7 @@ int qdev_init(DeviceState *dev) QEMU_WARN_UNUSED_RESULT;
 void qdev_init_nofail(DeviceState *dev);
 void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id,
                                  int required_for_version);
+HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev);
 void qdev_unplug(DeviceState *dev, Error **errp);
 void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev,
                                   DeviceState *dev, Error **errp);

trace-events

@@ -1562,6 +1562,7 @@ vfio_put_base_device(int fd) "close vdev->fd=%d"
 
 #hw/acpi/memory_hotplug.c
 mhp_acpi_invalid_slot_selected(uint32_t slot) "0x%"PRIx32
+mhp_acpi_ejecting_invalid_slot(uint32_t slot) "0x%"PRIx32
 mhp_acpi_read_addr_lo(uint32_t slot, uint32_t addr) "slot[0x%"PRIx32"] addr lo: 0x%"PRIx32
 mhp_acpi_read_addr_hi(uint32_t slot, uint32_t addr) "slot[0x%"PRIx32"] addr hi: 0x%"PRIx32
 mhp_acpi_read_size_lo(uint32_t slot, uint32_t size) "slot[0x%"PRIx32"] size lo: 0x%"PRIx32
@@ -1572,6 +1573,8 @@ mhp_acpi_write_slot(uint32_t slot) "set active slot: 0x%"PRIx32
 mhp_acpi_write_ost_ev(uint32_t slot, uint32_t ev) "slot[0x%"PRIx32"] OST EVENT: 0x%"PRIx32
 mhp_acpi_write_ost_status(uint32_t slot, uint32_t st) "slot[0x%"PRIx32"] OST STATUS: 0x%"PRIx32
 mhp_acpi_clear_insert_evt(uint32_t slot) "slot[0x%"PRIx32"] clear insert event"
+mhp_acpi_clear_remove_evt(uint32_t slot) "slot[0x%"PRIx32"] clear remove event"
+mhp_acpi_pc_dimm_deleted(uint32_t slot) "slot[0x%"PRIx32"] pc-dimm deleted"
 
 # hw/i386/pc.c
 mhp_pc_dimm_assigned_slot(int slot) "0x%d"