[Qemu-devel] [PATCH 10/35] dimm: implement dimm device abstraction

[Igor Mammedov <imammedo@redhat.com>]

Each hotplug-able memory slot is a DimmDevice.
A hot-add operation for a DIMM:
- creates a new DimmDevice and makes hotplug controller to map it into
  guest address space

Hotplug operations are done through normal device_add commands.
For migration case, all hotplugged DIMMs on source should be specified
on target's command line using '-device' option with properties set to
the same values as on source.

To simplify review, patch introduces only DimmDevice QOM skeleton that
will be extended by following patches to implement actual memory hotplug
and related functions.

Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
Signed-off-by: Igor Mammedov <imammedo@redhat.com>
---
 default-configs/i386-softmmu.mak   |   1 +
 default-configs/x86_64-softmmu.mak |   1 +
 hw/Makefile.objs                   |   1 +
 hw/mem/Makefile.objs               |   1 +
 hw/mem/dimm.c                      | 103 +++++++++++++++++++++++++++++++++++++
 include/hw/mem/dimm.h              |  65 +++++++++++++++++++++++
 6 files changed, 172 insertions(+)
 create mode 100644 hw/mem/Makefile.objs
 create mode 100644 hw/mem/dimm.c
 create mode 100644 include/hw/mem/dimm.h

diff --git a/default-configs/i386-softmmu.mak b/default-configs/i386-softmmu.mak
index 37ef90f..8e08841 100644
--- a/default-configs/i386-softmmu.mak
+++ b/default-configs/i386-softmmu.mak
@@ -44,3 +44,4 @@ CONFIG_APIC=y
 CONFIG_IOAPIC=y
 CONFIG_ICC_BUS=y
 CONFIG_PVPANIC=y
+CONFIG_MEM_HOTPLUG=y
diff --git a/default-configs/x86_64-softmmu.mak b/default-configs/x86_64-softmmu.mak
index 31bddce..66557ac 100644
--- a/default-configs/x86_64-softmmu.mak
+++ b/default-configs/x86_64-softmmu.mak
@@ -44,3 +44,4 @@ CONFIG_APIC=y
 CONFIG_IOAPIC=y
 CONFIG_ICC_BUS=y
 CONFIG_PVPANIC=y
+CONFIG_MEM_HOTPLUG=y
diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index d178b65..52a1464 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -29,6 +29,7 @@ devices-dirs-$(CONFIG_SOFTMMU) += usb/
 devices-dirs-$(CONFIG_VIRTIO) += virtio/
 devices-dirs-$(CONFIG_SOFTMMU) += watchdog/
 devices-dirs-$(CONFIG_SOFTMMU) += xen/
+devices-dirs-$(CONFIG_MEM_HOTPLUG) += mem/
 devices-dirs-y += core/
 common-obj-y += $(devices-dirs-y)
 obj-y += $(devices-dirs-y)
diff --git a/hw/mem/Makefile.objs b/hw/mem/Makefile.objs
new file mode 100644
index 0000000..7563ef5
--- /dev/null
+++ b/hw/mem/Makefile.objs
@@ -0,0 +1 @@
+common-obj-$(CONFIG_MEM_HOTPLUG) += dimm.o
diff --git a/hw/mem/dimm.c b/hw/mem/dimm.c
new file mode 100644
index 0000000..76f2a11
--- /dev/null
+++ b/hw/mem/dimm.c
@@ -0,0 +1,103 @@
+/*
+ * Dimm device for Memory Hotplug
+ *
+ * Copyright ProfitBricks GmbH 2012
+ * Copyright (C) 2014 Red Hat Inc
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>
+ */
+
+#include "hw/mem/dimm.h"
+#include "qemu/config-file.h"
+#include "qapi/visitor.h"
+
+static Property dimm_properties[] = {
+    DEFINE_PROP_UINT64("start", DimmDevice, start, 0),
+    DEFINE_PROP_UINT32("node", DimmDevice, node, 0),
+    DEFINE_PROP_INT32("slot", DimmDevice, slot, -1),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void dimm_get_size(Object *obj, Visitor *v, void *opaque,
+                          const char *name, Error **errp)
+{
+    int64_t value;
+    MemoryRegion *mr;
+    DimmDevice *dimm = DIMM(obj);
+
+    mr = host_memory_backend_get_memory(dimm->hostmem, errp);
+    value = memory_region_size(mr);
+
+    visit_type_int(v, &value, name, errp);
+}
+
+static void dimm_initfn(Object *obj)
+{
+    DimmDevice *dimm = DIMM(obj);
+
+    object_property_add(obj, "size", "int", dimm_get_size,
+                        NULL, NULL, NULL, &error_abort);
+    object_property_add_link(obj, "memdev", TYPE_MEMORY_BACKEND,
+                             (Object **)&dimm->hostmem,
+                             qdev_prop_allow_set_link_before_realize,
+                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
+                             &error_abort);
+}
+
+static void dimm_realize(DeviceState *dev, Error **errp)
+{
+    DimmDevice *dimm = DIMM(dev);
+
+    if (!dimm->hostmem) {
+        error_setg(errp, "'memdev' property is not set");
+        return;
+    }
+
+    if (!dev->id) {
+        error_setg(errp, "'id' property is not set");
+        return;
+    }
+}
+
+static MemoryRegion *dimm_get_memory_region(DimmDevice *dimm)
+{
+    return host_memory_backend_get_memory(dimm->hostmem, &error_abort);
+}
+
+static void dimm_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    DimmDeviceClass *ddc = DIMM_CLASS(oc);
+
+    dc->realize = dimm_realize;
+    dc->props = dimm_properties;
+
+    ddc->get_memory_region = dimm_get_memory_region;
+}
+
+static TypeInfo dimm_info = {
+    .name          = TYPE_DIMM,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(DimmDevice),
+    .instance_init = dimm_initfn,
+    .class_init    = dimm_class_init,
+    .class_size    = sizeof(DimmDeviceClass),
+};
+
+static void dimm_register_types(void)
+{
+    type_register_static(&dimm_info);
+}
+
+type_init(dimm_register_types)
diff --git a/include/hw/mem/dimm.h b/include/hw/mem/dimm.h
new file mode 100644
index 0000000..4bbf0ed
--- /dev/null
+++ b/include/hw/mem/dimm.h
@@ -0,0 +1,65 @@
+/*
+ * DIMM device
+ *
+ * Copyright ProfitBricks GmbH 2012
+ * Copyright (C) 2013 Red Hat Inc
+ *
+ * Authors:
+ *  Vasilis Liaskovitis <vasilis.liaskovitis@profitbricks.com>
+ *  Igor Mammedov <imammedo@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_DIMM_H
+#define QEMU_DIMM_H
+
+#include "exec/memory.h"
+#include "sysemu/hostmem.h"
+#include "hw/qdev.h"
+
+#define DEFAULT_DIMMSIZE (1024*1024*1024)
+
+#define TYPE_DIMM "dimm"
+#define DIMM(obj) \
+    OBJECT_CHECK(DimmDevice, (obj), TYPE_DIMM)
+#define DIMM_CLASS(oc) \
+    OBJECT_CLASS_CHECK(DimmDeviceClass, (oc), TYPE_DIMM)
+#define DIMM_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(DimmDeviceClass, (obj), TYPE_DIMM)
+
+/**
+ * DimmDevice:
+ * @start: starting guest physical address, where @DimmDevice is mapped.
+ *         Default value: 0, means that address is auto-allocated.
+ * @node: numa node to which @DimmDevice is attached.
+ * @slot: slot number into which @DimmDevice is plugged in.
+ *        Default value: -1, means that slot is auto-allocated.
+ * @hostmem: host memory backend providing memory for @DimmDevice
+ */
+typedef struct DimmDevice {
+    /* private */
+    DeviceState parent_obj;
+
+    /* public */
+    ram_addr_t start;
+    uint32_t node;
+    int32_t slot;
+    HostMemoryBackend *hostmem;
+} DimmDevice;
+
+/**
+ * DimmDeviceClass:
+ * @get_memory_region: returns #MemoryRegion associated with @dimm
+ */
+typedef struct DimmDeviceClass {
+    /* private */
+    DeviceClass parent_class;
+
+    /* public */
+    MemoryRegion *(*get_memory_region)(DimmDevice *dimm);
+} DimmDeviceClass;
+
+#endif
-- 
1.9.0