xen/acpi: ACPI memory hotplug

This patch implements real Xen acpi memory hotplug driver as module.
When loaded, it replaces Xen stub driver.

When an acpi memory device hotadd event occurs, it notifies OS and
invokes notification callback, adding related memory device and parsing
memory information, finally hypercall to xen hypervisor to add memory.
Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

drivers/xen/Kconfig

@@ -191,6 +191,17 @@ config XEN_STUB
 
 	  To enable Xen features like cpu and memory hotplug, select Y here.
 
+config XEN_ACPI_HOTPLUG_MEMORY
+	tristate "Xen ACPI memory hotplug"
+	depends on XEN_DOM0 && XEN_STUB && ACPI
+	default n
+	help
+	  This is Xen ACPI memory hotplug.
+
+	  Currently Xen only support ACPI memory hot-add. If you want
+	  to hot-add memory at runtime (the hot-added memory cannot be
+	  removed until machine stop), select Y/M here, otherwise select N.
+
 config XEN_ACPI_PROCESSOR
 	tristate "Xen ACPI processor"
 	depends on XEN && X86 && ACPI_PROCESSOR && CPU_FREQ

drivers/xen/Makefile

@@ -31,6 +31,7 @@ obj-$(CONFIG_XEN_MCE_LOG)		+= mcelog.o
 obj-$(CONFIG_XEN_PCIDEV_BACKEND)	+= xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)		+= xen-privcmd.o
 obj-$(CONFIG_XEN_STUB)			+= xen-stub.o
+obj-$(CONFIG_XEN_ACPI_HOTPLUG_MEMORY)	+= xen-acpi-memhotplug.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)	+= xen-acpi-processor.o
 xen-evtchn-y				:= evtchn.o
 xen-gntdev-y				:= gntdev.o

include/xen/interface/platform.h

@@ -324,10 +324,14 @@ struct xenpf_cpu_ol {
 };
 DEFINE_GUEST_HANDLE_STRUCT(xenpf_cpu_ol);
 
-/*
- * CMD 58 and 59 are reserved for cpu hotadd and memory hotadd,
- * which are already occupied at Xen hypervisor side.
- */
+#define XENPF_mem_hotadd	59
+struct xenpf_mem_hotadd {
+	uint64_t spfn;
+	uint64_t epfn;
+	uint32_t pxm;
+	uint32_t flags;
+};
+
 #define XENPF_core_parking     60
 struct xenpf_core_parking {
 	/* IN variables */
@@ -357,6 +361,7 @@ struct xen_platform_op {
 		struct xenpf_set_processor_pminfo set_pminfo;
 		struct xenpf_pcpuinfo          pcpu_info;
 		struct xenpf_cpu_ol            cpu_ol;
+		struct xenpf_mem_hotadd        mem_add;
 		struct xenpf_core_parking      core_parking;
 		uint8_t                        pad[128];
 	} u;