[Qemu-devel] [RESEND PATCH v4 6/6] acpi: Add hardware implementation for memory hot unplug

[Zhu Guihua]

This patch adds a new bit to memory hotplug IO port indicating that
EJ0 has been evaluated by guest OS. And call pc-dimm unplug cb to do
the real removal.

Signed-off-by: Zhu Guihua <address@hidden>
---
 docs/specs/acpi_mem_hotplug.txt   | 11 +++++++++--
 hw/acpi/memory_hotplug.c          | 21 +++++++++++++++++++--
 hw/core/qdev.c                    |  2 +-
 hw/i386/acpi-build.c              |  9 +++++++++
 hw/i386/acpi-dsdt-mem-hotplug.dsl | 10 ++++++++++
 include/hw/acpi/pc-hotplug.h      |  2 ++
 include/hw/qdev-core.h            |  1 +
 trace-events                      |  1 +
 8 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/docs/specs/acpi_mem_hotplug.txt b/docs/specs/acpi_mem_hotplug.txt
index 1290994..85cd4b8 100644
--- a/docs/specs/acpi_mem_hotplug.txt
+++ b/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 check event to OSPM was issued.
+              3-7: reserved and should be ignored by OSPM
       [0x15-0x17] reserved
 
   write access:
@@ -35,7 +37,12 @@ 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 check event for the
+                 selected memory device. if guest fails to eject device, it
+                 should send OST event about it and forget about device
+                 removal.
+              3-7: 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
diff --git a/hw/acpi/memory_hotplug.c b/hw/acpi/memory_hotplug.c
index 687b2f1..d6b8c89 100644
--- a/hw/acpi/memory_hotplug.c
+++ b/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;
@@ -122,19 +125,33 @@ static void acpi_memory_hotplug_write(void *opaque, 
hwaddr addr, uint64_t data,
         mdev = &mem_st->devs[mem_st->selector];
         mdev->ost_status = data;
         trace_mhp_acpi_write_ost_status(mem_st->selector, mdev->ost_status);
-        /* TODO: implement memory removal on guest signal */
 
         info = acpi_memory_device_status(mem_st->selector, mdev);
         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) { /* request removal of device */
+            mdev->is_removing = false;
+            trace_mhp_acpi_clear_remove_evt(mem_st->selector);
+            /*
+             * QEMU memory hot unplug is an asynchronous procedure. QEMU first
+             * calls pc-dimm unplug request cb to send a SCI to guest. When the
+             * guest OS finished handling the SCI, it evaluates ACPI EJ0, and
+             * QEMU calls pc-dimm unplug cb to remove memory device.
+             */
+            dev = DEVICE(mdev->dimm);
+            hotplug_ctrl = qdev_get_hotplug_handler(dev);
+            /* Call pc-dimm unplug cb. */
+            hotplug_handler_unplug(hotplug_ctrl, dev, NULL);
         }
         break;
+    default:
+        break;
     }
 
 }
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 6be5866..4676ffb 100644
--- a/hw/core/qdev.c
+++ b/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;
 
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index d0a5c85..1ba6102 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -929,6 +929,9 @@ 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(scope, field);
 
         field = aml_field(stringify(MEMORY_HOTPLUG_IO_REGION), aml_dword_acc);
@@ -972,6 +975,12 @@ 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);
         }
 
diff --git a/hw/i386/acpi-dsdt-mem-hotplug.dsl 
b/hw/i386/acpi-dsdt-mem-hotplug.dsl
index 1e9ec39..ef847e2 100644
--- a/hw/i386/acpi-dsdt-mem-hotplug.dsl
+++ b/hw/i386/acpi-dsdt-mem-hotplug.dsl
@@ -29,6 +29,7 @@
             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_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
@@ -55,6 +56,8 @@
                     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)
                     }
                     // TODO: handle memory eject request
                     Add(Local0, One, Local0) // goto next DIMM
@@ -156,5 +159,12 @@
                 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(One, MEMORY_SLOT_REMOVE_EVENT)
+                Release(MEMORY_SLOT_LOCK)
+            }
         } // Device()
     } // Scope()
diff --git a/include/hw/acpi/pc-hotplug.h b/include/hw/acpi/pc-hotplug.h
index efa6ed7..680810b 100644
--- a/include/hw/acpi/pc-hotplug.h
+++ b/include/hw/acpi/pc-hotplug.h
@@ -43,6 +43,7 @@
 #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_SLECTOR          MSEL
 #define MEMORY_SLOT_OST_EVENT        MOEV
 #define MEMORY_SLOT_OST_STATUS       MOSC
@@ -51,6 +52,7 @@
 #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
 
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 4e673f9..5b7acf1 100644
--- a/include/hw/qdev-core.h
+++ b/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);
diff --git a/trace-events b/trace-events
index 30eba92..e552355 100644
--- a/trace-events
+++ b/trace-events
@@ -1572,6 +1572,7 @@ 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"
 
 # hw/i386/pc.c
 mhp_pc_dimm_assigned_slot(int slot) "0x%d"
-- 
1.9.3