[Qemu-devel] [RESEND PATCH v3 6/8] acpi: Add hardware implementation for memory hot unplug.

[Tang Chen <tangchen@cn.fujitsu.com>]

This patch adds a bool member named "is_removing" to MemStatus indicating if
the memory device is being removed. It is set to true in acpi_memory_unplug_cb()
when doing memory hot-remove with device_del command, or write an
ACPI_EJECTION_IN_PROGRESS status to ACPI register when triggering memory
hot-remove in guest.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
 hw/acpi/memory_hotplug.c         | 62 ++++++++++++++++++++++++++++++++++++++--
 include/hw/acpi/acpi.h           | 14 +++++++++
 include/hw/acpi/memory_hotplug.h |  1 +
 3 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/hw/acpi/memory_hotplug.c b/hw/acpi/memory_hotplug.c
index c310b44..9074e7c 100644
--- a/hw/acpi/memory_hotplug.c
+++ b/hw/acpi/memory_hotplug.c
@@ -75,6 +75,7 @@ static uint64_t acpi_memory_hotplug_read(void *opaque, hwaddr addr,
     case 0x14: /* pack and return is_* fields */
         val |= mdev->is_enabled   ? 1 : 0;
         val |= mdev->is_inserting ? 2 : 0;
+        val |= mdev->is_removing  ? 4 : 0;
         trace_mhp_acpi_read_flags(mem_st->selector, val);
         break;
     default:
@@ -84,6 +85,51 @@ static uint64_t acpi_memory_hotplug_read(void *opaque, hwaddr addr,
     return val;
 }
 
+static void acpi_handle_eject(MemStatus *mdev)
+{
+    switch (mdev->ost_status) {
+    case ACPI_SUCCESS:
+        object_unparent(OBJECT(mdev->dimm));
+        mdev->is_removing = false;
+        mdev->dimm = NULL;
+        break;
+    case ACPI_EJECT_IN_PROGRESS:
+        /* For ejection triggered by hardware (device_del command),
+         * mdev->is_removing is set to true by acpi_memory_unplug_cb()
+         * before sending SCI. So we only handle ejection triggered by
+         * guest OS.
+	 */
+        if (mdev->ost_event == ACPI_OSPM_EJECT) {
+            mdev->is_enabled = false;
+            mdev->is_removing = true;
+        }
+        break;
+    case ACPI_FAILURE:
+    case ACPI_UNRECOGNIZED_NOTIFY:
+    case ACPI_EJECT_NOT_SUPPORTED:
+    case ACPI_EJECT_DEVICE_IN_USE:
+    case ACPI_EJECT_DEVICE_BUSY:
+    case ACPI_EJECT_DEPENDENCY_BUSY:
+        mdev->is_removing = false;
+        mdev->is_enabled = true;
+        break;
+    default:
+        break;
+    }
+}
+
+static void acpi_handle_ost_event(MemStatus *mdev)
+{
+    switch (mdev->ost_event) {
+    case ACPI_NOTIFY_EJECT_REQUEST:    /* Ejection triggered by hardware. */
+    case ACPI_OSPM_EJECT:              /* Ejection triggered by guest OS. */
+        acpi_handle_eject(mdev);
+        break;
+    default:
+        break;
+    }
+}
+
 static void acpi_memory_hotplug_write(void *opaque, hwaddr addr, uint64_t data,
                                       unsigned int size)
 {
@@ -121,21 +167,27 @@ 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);
+
+        acpi_handle_ost_event(mdev);
         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_enabled = false;
         }
+
+        break;
+    default:
         break;
     }
-
 }
 static const MemoryRegionOps acpi_memory_hotplug_ops = {
     .read = acpi_memory_hotplug_read,
@@ -198,6 +250,7 @@ void acpi_memory_plug_cb(ACPIREGS *ar, qemu_irq irq, MemHotplugState *mem_st,
 void acpi_memory_unplug_cb(ACPIREGS *ar, qemu_irq irq, MemHotplugState *mem_st,
                            DeviceState *dev, Error **errp)
 {
+    MemStatus *mdev;
     Error *local_err = NULL;
     int slot = object_property_get_int(OBJECT(dev), "slot", &local_err);
 
@@ -215,6 +268,9 @@ void acpi_memory_unplug_cb(ACPIREGS *ar, qemu_irq irq, MemHotplugState *mem_st,
         return;
     }
 
+    mdev = &mem_st->devs[slot];
+    mdev->is_removing = true;
+
     /* do ACPI magic */
     ar->gpe.sts[0] |= ACPI_MEMORY_HOTPLUG_STATUS;
     acpi_update_sci(ar, irq);
diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
index 1f678b4..e105e45 100644
--- a/include/hw/acpi/acpi.h
+++ b/include/hw/acpi/acpi.h
@@ -91,6 +91,20 @@
 /* PM2_CNT */
 #define ACPI_BITMASK_ARB_DISABLE                0x0001
 
+/* OST_EVENT */
+#define ACPI_NOTIFY_EJECT_REQUEST               0x03
+#define ACPI_OSPM_EJECT                         0x103
+
+/* OST_STATUS */
+#define ACPI_SUCCESS                            0x0
+#define ACPI_FAILURE                            0x1
+#define ACPI_UNRECOGNIZED_NOTIFY                0x2
+#define ACPI_EJECT_NOT_SUPPORTED                0x80
+#define ACPI_EJECT_DEVICE_IN_USE                0x81
+#define ACPI_EJECT_DEVICE_BUSY                  0x82
+#define ACPI_EJECT_DEPENDENCY_BUSY              0x83
+#define ACPI_EJECT_IN_PROGRESS                  0x84
+
 /* structs */
 typedef struct ACPIPMTimer ACPIPMTimer;
 typedef struct ACPIPM1EVT ACPIPM1EVT;
diff --git a/include/hw/acpi/memory_hotplug.h b/include/hw/acpi/memory_hotplug.h
index fc6b868..fe41268 100644
--- a/include/hw/acpi/memory_hotplug.h
+++ b/include/hw/acpi/memory_hotplug.h
@@ -11,6 +11,7 @@ typedef struct MemStatus {
     DeviceState *dimm;
     bool is_enabled;
     bool is_inserting;
+    bool is_removing;
     uint32_t ost_event;
     uint32_t ost_status;
 } MemStatus;
-- 
1.8.4.2