[Qemu-arm] [RFC PATCH 1/3] hw/arm/virt: add hotplug memory support

[Kwangwoo Lee]

Add hotplug memory feature on aarch64 virt platfom. This patch is
required to emulate a DIMM type memory like NVDIMM.

Signed-off-by: Kwangwoo Lee <address@hidden>
---
 default-configs/aarch64-softmmu.mak |   1 +
 hw/arm/virt.c                       | 110 ++++++++++++++++++++++++++++++++++++
 include/hw/arm/virt.h               |   3 +
 3 files changed, 114 insertions(+)

diff --git a/default-configs/aarch64-softmmu.mak 
b/default-configs/aarch64-softmmu.mak
index 2449483..5790cd2 100644
--- a/default-configs/aarch64-softmmu.mak
+++ b/default-configs/aarch64-softmmu.mak
@@ -7,3 +7,4 @@ CONFIG_AUX=y
 CONFIG_DDC=y
 CONFIG_DPCD=y
 CONFIG_XLNX_ZYNQMP=y
+CONFIG_MEM_HOTPLUG=y
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index a193b5a..f7ff411 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -58,6 +58,8 @@
 #include "hw/smbios/smbios.h"
 #include "qapi/visitor.h"
 #include "standard-headers/linux/input.h"
+#include "hw/mem/pc-dimm.h"
+#include "hw/acpi/acpi.h"
 
 /* Number of external interrupt lines to configure the GIC with */
 #define NUM_IRQS 256
@@ -91,6 +93,7 @@ typedef struct {
     bool secure;
     bool highmem;
     int32_t gic_version;
+    MemoryHotplugState hotplug_memory;
 } VirtMachineState;
 
 #define TYPE_VIRT_MACHINE   MACHINE_TYPE_NAME("virt")
@@ -1376,6 +1379,40 @@ static void machvirt_init(MachineState *machine)
     guest_info_state->machine_done.notify = virt_guest_info_machine_done;
     qemu_add_machine_init_done_notifier(&guest_info_state->machine_done);
 
+    /* initialize hotplug memory address space */
+    if (machine->ram_size < machine->maxram_size) {
+        ram_addr_t hotplug_mem_size = machine->maxram_size - machine->ram_size;
+
+        if (machine->ram_slots > ACPI_MAX_RAM_SLOTS) {
+            error_report("unsupported amount of memory slots: %"PRIu64,
+                     machine->ram_slots);
+            exit(EXIT_FAILURE);
+        }
+
+        if (QEMU_ALIGN_UP(machine->maxram_size,
+                     TARGET_PAGE_SIZE) != machine->maxram_size) {
+            error_report("maximum memory size must by aligned to multiple of "
+                     "%d bytes", TARGET_PAGE_SIZE);
+            exit(EXIT_FAILURE);
+        }
+
+        vms->hotplug_memory.base =
+                     ROUND_UP(vbi->memmap[VIRT_MEM].base + machine->ram_size,
+                                              ARCH_VIRT_HOTPLUG_MEM_ALIGN);
+
+        if ((vms->hotplug_memory.base + hotplug_mem_size) <
+            hotplug_mem_size) {
+            error_report("unsupported amount of maximum memory: " RAM_ADDR_FMT,
+                     machine->maxram_size);
+            exit(EXIT_FAILURE);
+        }
+
+        memory_region_init(&vms->hotplug_memory.mr, OBJECT(vms),
+                           "hotplug-memory", hotplug_mem_size);
+        memory_region_add_subregion(sysmem, vms->hotplug_memory.base,
+                                    &vms->hotplug_memory.mr);
+    }
+
     vbi->bootinfo.ram_size = machine->ram_size;
     vbi->bootinfo.kernel_filename = machine->kernel_filename;
     vbi->bootinfo.kernel_cmdline = machine->kernel_cmdline;
@@ -1448,9 +1485,75 @@ static void virt_set_gic_version(Object *obj, const char 
*value, Error **errp)
     }
 }
 
+static void virt_dimm_plug(HotplugHandler *hotplug_dev,
+                         DeviceState *dev, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(hotplug_dev);
+    PCDIMMDevice *dimm = PC_DIMM(dev);
+    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
+    MemoryRegion *mr = ddc->get_memory_region(dimm);
+    Error *local_err = NULL;
+    uint64_t align = memory_region_get_alignment(mr);
+
+    pc_dimm_memory_plug(dev, &vms->hotplug_memory, mr, align, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+out:
+    error_propagate(errp, local_err);
+}
+
+static void virt_dimm_unplug(HotplugHandler *hotplug_dev,
+                           DeviceState *dev, Error **errp)
+{
+    VirtMachineState *vms = VIRT_MACHINE(hotplug_dev);
+    PCDIMMDevice *dimm = PC_DIMM(dev);
+    PCDIMMDeviceClass *ddc = PC_DIMM_GET_CLASS(dimm);
+    MemoryRegion *mr = ddc->get_memory_region(dimm);
+    Error *local_err = NULL;
+
+    pc_dimm_memory_unplug(dev, &vms->hotplug_memory, mr);
+    object_unparent(OBJECT(dev));
+
+    error_propagate(errp, local_err);
+}
+
+static void virt_machinedevice_plug_cb(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        virt_dimm_plug(hotplug_dev, dev, errp);
+    } else {
+        error_setg(errp, "acpi: device plug request for not supported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
+}
+
+static void virt_machinedevice_unplug_cb(HotplugHandler *hotplug_dev,
+                                        DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        virt_dimm_unplug(hotplug_dev, dev, errp);
+    } else {
+        error_setg(errp, "acpi: device unplug for not supported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
+}
+
+static HotplugHandler *virt_get_hotplug_handler(MachineState *machine,
+                                             DeviceState *dev)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        return HOTPLUG_HANDLER(machine);
+    }
+    return NULL;
+}
+
 static void virt_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
 
     mc->init = machvirt_init;
     /* Start max_cpus at the maximum QEMU supports. We'll further restrict
@@ -1462,6 +1565,9 @@ static void virt_machine_class_init(ObjectClass *oc, void 
*data)
     mc->block_default_type = IF_VIRTIO;
     mc->no_cdrom = 1;
     mc->pci_allow_0_address = true;
+    mc->get_hotplug_handler = virt_get_hotplug_handler;
+    hc->plug = virt_machinedevice_plug_cb;
+    hc->unplug = virt_machinedevice_unplug_cb;
 }
 
 static const TypeInfo virt_machine_info = {
@@ -1471,6 +1577,10 @@ static const TypeInfo virt_machine_info = {
     .instance_size = sizeof(VirtMachineState),
     .class_size    = sizeof(VirtMachineClass),
     .class_init    = virt_machine_class_init,
+    .interfaces = (InterfaceInfo[]) {
+         { TYPE_HOTPLUG_HANDLER },
+         { }
+    },
 };
 
 static void machvirt_machine_init(void)
diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index 9650193..35aa3cc 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -45,6 +45,9 @@
 
 #define PPI(irq) ((irq) + 16)
 
+/* 1GB alignment for hotplug memory region */
+#define ARCH_VIRT_HOTPLUG_MEM_ALIGN (1ULL << 30)
+
 enum {
     VIRT_FLASH,
     VIRT_MEM,
-- 
2.5.0