[Qemu-devel] [RFC PATCH 7/7] hw/arm/virt-acpi-build: Add cpu hotplug support in ACPI

[Shannon Zhao]

Add cpu hotplug support in ACPI.

Signed-off-by: Shannon Zhao <address@hidden>
---
 hw/acpi/aml-build.c              |  135 ++++++++++++++++++++++++++++
 hw/acpi/virt-hotplug.c           |   11 +++
 hw/arm/virt-acpi-build.c         |  179 +++++++++++++++++++++++++++++++++++++-
 hw/arm/virt.c                    |    1 +
 include/hw/acpi/aml-build.h      |   13 +++
 include/hw/acpi/virt-hotplug.h   |    2 +-
 include/hw/arm/virt-acpi-build.h |    1 +
 7 files changed, 337 insertions(+), 5 deletions(-)

diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
index 5e0c40b..023e055 100644
--- a/hw/acpi/aml-build.c
+++ b/hw/acpi/aml-build.c
@@ -468,6 +468,21 @@ Aml *aml_arg(int pos)
     return var;
 }
 
+Aml *aml_index(Aml *val, Aml *index)
+{
+    Aml *var = aml_opcode(0x88 /* IndexOp */);
+    aml_append(var, val);
+    aml_append(var, index);
+    return var;
+}
+
+Aml *aml_derefof(Aml *val)
+{
+    Aml *var = aml_opcode(0x83 /* DerefofOp */);
+    aml_append(var, val);
+    return var;
+}
+
 /* ACPI 1.0b: 16.2.5.4 Type 2 Opcodes Encoding: DefStore */
 Aml *aml_store(Aml *val, Aml *target)
 {
@@ -496,6 +511,14 @@ Aml *aml_notify(Aml *arg1, Aml *arg2)
     return var;
 }
 
+/* helper to call method with none argument */
+Aml *aml_call0(const char *method)
+{
+    Aml *var = aml_alloc();
+    build_append_namestring(var->buf, "%s", method);
+    return var;
+}
+
 /* helper to call method with 1 argument */
 Aml *aml_call1(const char *method, Aml *arg1)
 {
@@ -539,6 +562,48 @@ Aml *aml_call4(const char *method, Aml *arg1, Aml *arg2, 
Aml *arg3, Aml *arg4)
 }
 
 /*
+ * ACPI 5.0 19.5.53 GpioInt (GPIO Interrupt Connection Resource Descriptor 
Macro)
+ */
+Aml *aml_gpio_int(uint8_t edge, uint8_t polarity, uint8_t share, uint8_t wake,
+                  int8_t pin_cfg, int32_t pin_num, const char *name)
+{
+    Aml *var = aml_alloc();
+    uint8_t flags = edge & (polarity >> 1) & (share >> 3) & (wake >> 4) & 0x1F;
+    uint16_t length = 0x18 + sizeof(name);
+
+    build_append_byte(var->buf, 0x8C); /* GpioInt Resource Descriptor */
+    build_append_byte(var->buf, length & 0xff); /* Length, bits[7:0] */
+    build_append_byte(var->buf, (length >> 8) & 0xff); /* Length, bits[15:8] */
+    build_append_byte(var->buf, 1); /* Revision ID */
+    build_append_byte(var->buf, 0); /* GPIO Connection Type 0x00 = Interrupt 
Connection */
+    build_append_byte(var->buf, 0); /* General Flags, bits[7:0] */
+    build_append_byte(var->buf, 0); /* General Flags, bits[15:8] */
+    build_append_byte(var->buf, flags); /* Interrupt and IO Flags, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Interrupt and IO Flags, bits[15:8] */
+    build_append_byte(var->buf, pin_cfg); /* Pin Configuration 0 = Default 1 = 
Pull-up
+                                           * 2 = Pull-down 3 = No Pull */
+    build_append_byte(var->buf, 0); /* Output Drive Strength, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Output Drive Strength, bits[15:8] */
+    build_append_byte(var->buf, 0); /* Debounce timeout, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Debounce timeout, bits[15:8] */
+
+    build_append_byte(var->buf, 0x16); /* Pin Table Offset, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Pin Table Offset, bits[15:8] */
+    build_append_byte(var->buf, 0); /* Resource Source Index */
+    build_append_byte(var->buf, 0x18); /* Resource Source Name, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Resource Source Name, bits[15:8] */
+    build_append_byte(var->buf, length & 0xff); /* Vendor Data Offset, 
bits[7:0] */
+    build_append_byte(var->buf, (length >> 8) & 0xff); /* Vendor Data Offset, 
bits[15:8] */
+    build_append_byte(var->buf, 0); /* Vendor Data Length, bits[7:0] */
+    build_append_byte(var->buf, 0); /* Vendor Data Length, bits[15:8] */
+    build_append_byte(var->buf, pin_num & 0xff); /* Pin Number, bits[7:0] */
+    build_append_byte(var->buf, (pin_num >> 8) & 0xff); /* Pin Number, 
bits[15:8] */
+    build_append_namestring(var->buf, "%s", name); /* Resource Source */
+
+    return var;
+}
+
+/*
  * ACPI 1.0: 6.4.3.4 Memory32Fixed (Memory Resource Descriptor Macro)
  */
 Aml *aml_memory32_fixed(uint64_t addr, uint64_t size, uint8_t rw_flag)
@@ -615,6 +680,43 @@ Aml *aml_irq_no_flags(uint8_t irq)
     return var;
 }
 
+/* ACPI 1.0: 16.2.3 Operators: DefIncrement */
+Aml *aml_increment(Aml *arg)
+{
+    Aml *var = aml_opcode(0x75 /* IncrementOp */);
+    aml_append(var, arg);
+    build_append_int(var->buf, 0x00); /* NullNameOp */
+    return var;
+}
+
+/* ACPI 1.0: 16.2.3 Operators: DefShiftRight */
+Aml *aml_shiftright(Aml *arg1, Aml *arg2, Aml *arg3)
+{
+    Aml *var = aml_opcode(0x7A /* ShiftRightOp */);
+    aml_append(var, arg1);
+    aml_append(var, arg2);
+    aml_append(var, arg3);
+    build_append_int(var->buf, 0x00); /* NullNameOp */
+    return var;
+}
+
+/* ACPI 1.0: 16.2.3 Operators: DefSizeof */
+Aml *aml_sizeof(Aml *arg)
+{
+    Aml *var = aml_opcode(0x87 /* SizeofOp */);
+    aml_append(var, arg);
+    build_append_int(var->buf, 0x00); /* NullNameOp */
+    return var;
+}
+
+/* ACPI 1.0: 16.2.3 Operators: DefLNot */
+Aml *aml_not(Aml *arg)
+{
+    Aml *var = aml_opcode(0x92 /* LNotOp */);
+    aml_append(var, arg);
+    build_append_int(var->buf, 0x00); /* NullNameOp */
+    return var;
+}
 /* ACPI 1.0b: 16.2.5.4 Type 2 Opcodes Encoding: DefLEqual */
 Aml *aml_equal(Aml *arg1, Aml *arg2)
 {
@@ -625,6 +727,16 @@ Aml *aml_equal(Aml *arg1, Aml *arg2)
     return var;
 }
 
+/* ACPI 1.0: 16.2.3 Operators: DefLLess */
+Aml *aml_less(Aml *arg1, Aml *arg2)
+{
+    Aml *var = aml_opcode(0x95 /* LLessOp */);
+    aml_append(var, arg1);
+    aml_append(var, arg2);
+    build_append_int(var->buf, 0x00); /* NullNameOp */
+    return var;
+}
+
 /* ACPI 1.0b: 16.2.5.3 Type 1 Opcodes Encoding: DefIfElse */
 Aml *aml_if(Aml *predicate)
 {
@@ -633,6 +745,29 @@ Aml *aml_if(Aml *predicate)
     return var;
 }
 
+/* ACPI 1.0: 16.2.3 Operators: DefElse */
+Aml *aml_else(void)
+{
+    Aml *var = aml_bundle(0xA1 /* ElseOp */, AML_PACKAGE);
+    return var;
+}
+
+/* ACPI 1.0: 16.2.3 Operators: DefWhile */
+Aml *aml_while(Aml *predicate)
+{
+    Aml *var = aml_bundle(0xA2 /* DefWhile */, AML_PACKAGE);
+    aml_append(var, predicate);
+    return var;
+}
+
+/* ACPI 1.0: 16.2.3 Operators: DefSleep */
+Aml *aml_sleep(const uint64_t msectime)
+{
+    Aml *var = aml_bundle(0x22 /* SleepOp */, AML_EXT_PACKAGE);
+    build_append_int(var->buf, msectime);
+    return var;
+}
+
 /* ACPI 1.0b: 16.2.5.2 Named Objects Encoding: DefMethod */
 Aml *aml_method(const char *name, int arg_count)
 {
diff --git a/hw/acpi/virt-hotplug.c b/hw/acpi/virt-hotplug.c
index 47da078..c9a837d 100644
--- a/hw/acpi/virt-hotplug.c
+++ b/hw/acpi/virt-hotplug.c
@@ -85,6 +85,17 @@ static int virt_hotplug_initfn(SysBusDevice *sbd)
     return 0;
 }
 
+Object *virt_hotplug_find(void)
+{
+    bool ambig;
+    Object *o = object_resolve_path_type("", TYPE_VIRT_HOTPLUG, &ambig);
+
+    if (ambig || !o) {
+        return NULL;
+    }
+    return o;
+}
+
 void virt_hotplug_init(DeviceState **virt_hotplug)
 {
     DeviceState *dev;
diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index 4f26551..a719487 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -38,6 +38,7 @@
 #include "target-arm/cpu.h"
 #include "hw/acpi/acpi-defs.h"
 #include "hw/acpi/acpi.h"
+#include "hw/acpi/virt-hotplug.h"
 #include "hw/nvram/fw_cfg.h"
 #include "hw/acpi/bios-linker-loader.h"
 #include "hw/loader.h"
@@ -179,7 +180,7 @@ static void acpi_dsdt_add_virtio(Aml *scope, const hwaddr 
*mmio_addrs,
 static void acpi_dsdt_add_gpio(Aml *scope, const hwaddr *gpio_addrs,
                                            const int *gpio_irq)
 {
-    Aml *dev, *crs;
+    Aml *dev, *crs, *aei, *method;
 
     dev = aml_device("GPO0");
     aml_append(dev, aml_name_decl("_HID", aml_string("LNRO0009")));
@@ -193,9 +194,172 @@ static void acpi_dsdt_add_gpio(Aml *scope, const hwaddr 
*gpio_addrs,
                aml_interrupt(0x01, *gpio_irq + 32));
     aml_append(dev, aml_name_decl("_CRS", crs));
 
+    aei = aml_resource_template();
+    aml_append(aei, aml_gpio_int(1, 2, 0, 0, 1, 2, "\\_SB.GPO0"));
+    aml_append(dev, aml_name_decl("_AEI", aei));
+    /* _E02 for cpu hotplug */
+    method = aml_method("_E02", 0);
+    aml_append(method, aml_call0("\\_SB.PRSC"));
+    aml_append(dev, method);
+
     aml_append(scope, dev);
 }
 
+static void acpi_dsdt_add_cpu_hotplug(Aml *scope, int max_cpus,
+                const hwaddr *cpu_hotplug_addr, VirtAcpiCpuInfo *cpuinfo)
+{
+    Aml *dev, *crs, *field, *method, *ifctx, *elsectx, *ifctx1, *whilectx;
+    Aml *local0, *local1, *local2, *local3, *local4, *pkg, *buffer;
+    int i;
+
+    /* create PRES device and its _CRS to reserve CPU hotplug MMIO */
+    dev = aml_device("PRES");
+    aml_append(dev, aml_name_decl("_HID", aml_string("PNP0A06")));
+    aml_append(dev, aml_name_decl("_UID", aml_string("CPU Hotplug 
Resources")));
+    aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
+    crs = aml_resource_template();
+    aml_append(crs,
+               aml_memory32_fixed(cpu_hotplug_addr[0], cpu_hotplug_addr[1], 
0x01));
+    aml_append(dev, aml_name_decl("_CRS", crs));
+    aml_append(scope, dev);
+
+    /* declare CPU hotplug MMIO region and PRS field to access it */
+    aml_append(scope, aml_operation_region(
+        "PRST", aml_system_memory, cpu_hotplug_addr[0], cpu_hotplug_addr[1]));
+    field = aml_field("PRST", aml_byte_acc);
+    aml_append(field, aml_named_field("PRS", 256));
+    aml_append(scope, field);
+
+    /* build Processor object for each processor */
+    for (i = 0; i < max_cpus; i++) {
+        dev = aml_processor(i, 0, 0, "CP%.02X", i);
+
+        method = aml_method("_MAT", 0);
+        aml_append(method, aml_return(aml_call1("CPMA", aml_int(i))));
+        aml_append(dev, method);
+
+        method = aml_method("_STA", 0);
+        aml_append(method, aml_return(aml_call1("CPST", aml_int(i))));
+        aml_append(dev, method);
+
+        method = aml_method("_EJ0", 1);
+        aml_append(method,
+            aml_return(aml_call2("CPEJ", aml_int(i), aml_arg(0))));
+        aml_append(dev, method);
+
+        aml_append(scope, dev);
+    }
+
+    /* build this code:
+     *   Method(NTFY, 2) {If (LEqual(Arg0, 0x00)) {Notify(CP00, Arg1)} ...}
+     */
+    /* Arg0 = Processor ID = APIC ID */
+    method = aml_method("NTFY", 2);
+    for (i = 0; i < max_cpus; i++) {
+        ifctx = aml_if(aml_equal(aml_arg(0), aml_int(i)));
+        aml_append(ifctx,
+            aml_notify(aml_name("CP%.02X", i), aml_arg(1))
+        );
+        aml_append(method, ifctx);
+    }
+    aml_append(scope, method);
+
+    /* build "Name(CPON, Package() { One, One, ..., Zero, Zero, ... })"
+     *
+     * Note: The ability to create variable-sized packages was first
+     * ntroduced in ACPI 2.0. ACPI 1.0 only allowed fixed-size packages
+     * ith up to 255 elements. Windows guests up to win2k8 fail when
+     * VarPackageOp is used.
+     */
+    pkg = max_cpus <= 255 ? aml_package(max_cpus) :
+                             aml_varpackage(max_cpus);
+
+    for (i = 0; i < max_cpus; i++) {
+        uint8_t b = test_bit(i, cpuinfo->found_cpus) ? 0x01 : 0x00;
+        aml_append(pkg, aml_int(b));
+    }
+    aml_append(scope, aml_name_decl("CPON", pkg));
+
+    /* Add CPMA method  */
+    method = aml_method("CPMA", 1);
+    local0 = aml_local(0);
+    aml_append(method,
+        aml_store(aml_derefof(aml_index(pkg, aml_arg(0))), local0));
+    buffer = aml_buffer();
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x08));
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x0));
+    aml_append(buffer, aml_int(0x0));
+    local1 = aml_local(1);
+    aml_append(method, aml_store(buffer, local1));
+    aml_append(method, aml_store(aml_arg(0), aml_index(local1, aml_int(2))));
+    aml_append(method, aml_store(aml_arg(0), aml_index(local1, aml_int(3))));
+    aml_append(method, aml_store(local0, aml_index(local1, aml_int(4))));
+    aml_append(method, aml_return(local1));
+    aml_append(scope, method);
+
+    /* Add CPST method  */
+    method = aml_method("CPST", 1);
+    local0 = aml_local(0);
+    aml_append(method,
+        aml_store(aml_derefof(aml_index(pkg, aml_arg(0))), local0));
+    ifctx = aml_if(local0);
+    aml_append(ifctx, aml_return(aml_int(0xF)));
+    aml_append(method, ifctx);
+    elsectx = aml_else();
+    aml_append(elsectx, aml_return(aml_int(0x0)));
+    aml_append(method, elsectx);
+    aml_append(scope, method);
+
+    /* Add CPEJ method  */
+    method = aml_method("CPEJ", 2);
+    aml_append(method, aml_sleep(200));
+    aml_append(scope, method);
+
+    /* Add PRSC method  */
+    method = aml_method("PRSC", 0);
+    local4 = aml_local(4);
+    aml_append(method, aml_store(field, local4));
+    local2 = aml_local(2);
+    aml_append(method, aml_store(aml_int(0), local2));
+    local0 = aml_local(0);
+    aml_append(method, aml_store(aml_int(0), local0));
+
+    whilectx = aml_while(aml_less(local0, aml_sizeof(pkg)));
+    local1 = aml_local(1);
+    aml_append(whilectx,
+        aml_store(aml_derefof(aml_index(pkg, local0)), local1));
+    ifctx = aml_if(aml_and(local0, aml_int(0x07)));
+    aml_append(ifctx, aml_shiftright(local2, aml_int(0x1), local2));
+    aml_append(whilectx, ifctx);
+    elsectx = aml_else();
+    aml_append(elsectx,
+        aml_store(aml_derefof(aml_index(local4,
+                  aml_shiftright(local0, aml_int(0x3), local0))), local0)
+    );
+    aml_append(whilectx, elsectx);
+    local3 = aml_local(3);
+    aml_append(whilectx, aml_store(aml_and(local2, aml_int(0x1)), local3));
+    ifctx = aml_if(aml_not(aml_equal(local1, local3)));
+    aml_append(ifctx, aml_store(local3, aml_index(pkg, local0)));
+    ifctx1 = aml_if(aml_equal(local3, aml_int(0x1)));
+    aml_append(ifctx1, aml_call2("NTFY", local0, aml_int(0x1)));
+    aml_append(ifctx, ifctx1);
+    elsectx = aml_else();
+    aml_append(elsectx, aml_call2("NTFY", local0, aml_int(0x3)));
+    aml_append(ifctx, elsectx);
+    aml_append(whilectx, ifctx);
+
+    aml_append(whilectx, aml_increment(local0));
+
+    aml_append(method, whilectx);
+    aml_append(scope, method);
+}
+
 /* RSDP */
 static GArray *
 build_rsdp(GArray *rsdp_table, GArray *linker, unsigned rsdt)
@@ -348,22 +512,29 @@ build_fadt(GArray *table_data, GArray *linker, uint64_t 
dsdt)
 
 /* DSDT */
 static void
-build_dsdt(Aml *table_data, GArray *linker, VirtGuestInfo *guest_info)
+build_dsdt(Aml *table_data, GArray *linker, VirtGuestInfo *guest_info,
+           VirtAcpiCpuInfo *cpuinfo)
 {
     Aml *scope, *dsdt;
     const struct acpi_dsdt_info *info = guest_info->dsdt_info;
+    Object *virt_hotplug = virt_hotplug_find();
 
     dsdt = aml_def_block("DSDT", 1, ACPI_BUILD_APPNAME6,
                           ACPI_BUILD_APPNAME4, 1,
                           ACPI_BUILD_APPNAME4_HEX, 1);
     scope = aml_scope("\\_SB");
-    acpi_dsdt_add_cpus(scope, guest_info->max_cpus);
     acpi_dsdt_add_uart(scope, info->uart_addr, info->uart_irq);
     acpi_dsdt_add_rtc(scope, info->rtc_addr, info->rtc_irq);
     acpi_dsdt_add_flash(scope, info->flash_addr);
     acpi_dsdt_add_virtio(scope, info->virtio_mmio_addr,
              info->virtio_mmio_irq, info->virtio_mmio_num);
     acpi_dsdt_add_gpio(scope, info->gpio_addr, info->gpio_irq);
+    if (virt_hotplug) {
+        acpi_dsdt_add_cpu_hotplug(scope, guest_info->max_cpus,
+                                  info->cpu_hotplug_addr, cpuinfo);
+    } else {
+        acpi_dsdt_add_cpus(scope, guest_info->max_cpus);
+    }
 
     aml_append(dsdt, scope);
     aml_append(table_data, dsdt);
@@ -410,7 +581,7 @@ void virt_acpi_build(VirtGuestInfo *guest_info, 
AcpiBuildTables *tables)
 
     /* DSDT is pointed to by FADT */
     dsdt = tables_blob->len;
-    build_dsdt(tables->table_data, tables->linker, guest_info);
+    build_dsdt(tables->table_data, tables->linker, guest_info, &cpuinfo);
 
     /* FADT MADT GTDT pointed to by XSDT */
     acpi_add_table(table_offsets, tables_blob);
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 760afbb..4add9f5 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -168,6 +168,7 @@ static const struct acpi_dsdt_info dsdt_info = {
     .virtio_mmio_num = NUM_VIRTIO_TRANSPORTS,
     .gpio_addr = &a15memmap[VIRT_GPIO].base,
     .gpio_irq = &a15irqmap[VIRT_GPIO],
+    .cpu_hotplug_addr = &a15memmap[VIRT_CPU_HOTPLUG].base,
     .rtc_addr = &a15memmap[VIRT_RTC].base,
     .rtc_irq = &a15irqmap[VIRT_RTC],
     .flash_addr = &a15memmap[VIRT_FLASH].base,
diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
index eb9ba0d..5e43557 100644
--- a/include/hw/acpi/aml-build.h
+++ b/include/hw/acpi/aml-build.h
@@ -155,17 +155,27 @@ Aml *aml_name_decl(const char *name, Aml *val);
 Aml *aml_return(Aml *val);
 Aml *aml_int(const uint64_t val);
 Aml *aml_arg(int pos);
+Aml *aml_index(Aml *val, Aml *index);
+Aml *aml_derefof(Aml *val);
 Aml *aml_store(Aml *val, Aml *target);
 Aml *aml_and(Aml *arg1, Aml *arg2);
 Aml *aml_notify(Aml *arg1, Aml *arg2);
+Aml *aml_call0(const char *method);
 Aml *aml_call1(const char *method, Aml *arg1);
 Aml *aml_call2(const char *method, Aml *arg1, Aml *arg2);
 Aml *aml_call3(const char *method, Aml *arg1, Aml *arg2, Aml *arg3);
 Aml *aml_call4(const char *method, Aml *arg1, Aml *arg2, Aml *arg3, Aml *arg4);
+Aml *aml_gpio_int(uint8_t edge, uint8_t polarity, uint8_t share, uint8_t wake,
+                  int8_t pin_cfg, int32_t pin_num, const char *name);
 Aml *aml_memory32_fixed(uint64_t addr, uint64_t size, uint8_t rw_flag);
 Aml *aml_interrupt(uint8_t irq_flags, int irq);
 Aml *aml_io(AmlIODecode dec, uint16_t min_base, uint16_t max_base,
             uint8_t aln, uint8_t len);
+Aml *aml_increment(Aml *arg);
+Aml *aml_shiftright(Aml *arg1, Aml *arg2, Aml *arg3);
+Aml *aml_sizeof(Aml *arg);
+Aml *aml_not(Aml *arg);
+Aml *aml_less(Aml *arg1, Aml *arg2);
 Aml *aml_operation_region(const char *name, AmlRegionSpace rs,
                           uint32_t offset, uint32_t len);
 Aml *aml_irq_no_flags(uint8_t irq);
@@ -208,6 +218,9 @@ Aml *aml_scope(const char *name_format, ...) 
GCC_FMT_ATTR(1, 2);
 Aml *aml_device(const char *name_format, ...) GCC_FMT_ATTR(1, 2);
 Aml *aml_method(const char *name, int arg_count);
 Aml *aml_if(Aml *predicate);
+Aml *aml_else(void);
+Aml *aml_while(Aml *predicate);
+Aml *aml_sleep(const uint64_t msectime);
 Aml *aml_package(uint8_t num_elements);
 Aml *aml_buffer(void);
 Aml *aml_resource_template(void);
diff --git a/include/hw/acpi/virt-hotplug.h b/include/hw/acpi/virt-hotplug.h
index 8f94235..aad3381 100644
--- a/include/hw/acpi/virt-hotplug.h
+++ b/include/hw/acpi/virt-hotplug.h
@@ -7,5 +7,5 @@
 #define VIRT_CPU_HOTPLUG_MMIO_BASE 0x09600000
 
 void virt_hotplug_init(DeviceState **virt_hotplug);
-
+Object *virt_hotplug_find(void);
 #endif
diff --git a/include/hw/arm/virt-acpi-build.h b/include/hw/arm/virt-acpi-build.h
index de8d4c6..b183b42 100644
--- a/include/hw/arm/virt-acpi-build.h
+++ b/include/hw/arm/virt-acpi-build.h
@@ -49,6 +49,7 @@ struct acpi_dsdt_info {
     int virtio_mmio_num;
     const hwaddr *gpio_addr;
     const int *gpio_irq;
+    const hwaddr *cpu_hotplug_addr;
     const hwaddr *rtc_addr;
     const int *rtc_irq;
     const hwaddr *flash_addr;
-- 
1.7.1