hw/loongarch: Add acpi ged support

Loongarch virt machine uses general hardware reduces acpi method, rather
than LS7A acpi device. Now only power management function is used in
acpi ged device, memory hotplug will be added later. Also acpi tables
such as RSDP/RSDT/FADT etc.

The acpi table has submited to acpi spec, and will release soon.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Message-Id: <20220712083206.4187715-6-yangxiaojuan@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

4 files changed, 687 insertions, 3 deletions

diff --git a/hw/loongarch/Kconfig b/hw/loongarch/Kconfig
index 610552e..a99aa38 100644
--- a/hw/loongarch/Kconfig
+++ b/hw/loongarch/Kconfig
@@ -15,3 +15,5 @@ config LOONGARCH_VIRT
     select LOONGARCH_EXTIOI
     select LS7A_RTC
     select SMBIOS
+    select ACPI_PCI
+    select ACPI_HW_REDUCED
diff --git a/hw/loongarch/acpi-build.c b/hw/loongarch/acpi-build.c
new file mode 100644
index 0000000..b95b83b
--- /dev/null
+++ b/hw/loongarch/acpi-build.c
@@ -0,0 +1,609 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Support for generating ACPI tables and passing them to Guests
+ *
+ * Copyright (C) 2021 Loongson Technology Corporation Limited
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/bitmap.h"
+#include "hw/pci/pci.h"
+#include "hw/core/cpu.h"
+#include "target/loongarch/cpu.h"
+#include "hw/acpi/acpi-defs.h"
+#include "hw/acpi/acpi.h"
+#include "hw/nvram/fw_cfg.h"
+#include "hw/acpi/bios-linker-loader.h"
+#include "migration/vmstate.h"
+#include "hw/mem/memory-device.h"
+#include "sysemu/reset.h"
+
+/* Supported chipsets: */
+#include "hw/pci-host/ls7a.h"
+#include "hw/loongarch/virt.h"
+#include "hw/acpi/aml-build.h"
+
+#include "hw/acpi/utils.h"
+#include "hw/acpi/pci.h"
+
+#include "qom/qom-qobject.h"
+
+#include "hw/acpi/generic_event_device.h"
+
+#define ACPI_BUILD_ALIGN_SIZE             0x1000
+#define ACPI_BUILD_TABLE_SIZE             0x20000
+
+#ifdef DEBUG_ACPI_BUILD
+#define ACPI_BUILD_DPRINTF(fmt, ...)        \
+    do {printf("ACPI_BUILD: " fmt, ## __VA_ARGS__); } while (0)
+#else
+#define ACPI_BUILD_DPRINTF(fmt, ...)
+#endif
+
+/* build FADT */
+static void init_common_fadt_data(AcpiFadtData *data)
+{
+    AcpiFadtData fadt = {
+        /* ACPI 5.0: 4.1 Hardware-Reduced ACPI */
+        .rev = 5,
+        .flags = ((1 << ACPI_FADT_F_HW_REDUCED_ACPI) |
+                  (1 << ACPI_FADT_F_RESET_REG_SUP)),
+
+        /* ACPI 5.0: 4.8.3.7 Sleep Control and Status Registers */
+        .sleep_ctl = {
+            .space_id = AML_AS_SYSTEM_MEMORY,
+            .bit_width = 8,
+            .address = VIRT_GED_REG_ADDR + ACPI_GED_REG_SLEEP_CTL,
+        },
+        .sleep_sts = {
+            .space_id = AML_AS_SYSTEM_MEMORY,
+            .bit_width = 8,
+            .address = VIRT_GED_REG_ADDR + ACPI_GED_REG_SLEEP_STS,
+        },
+
+        /* ACPI 5.0: 4.8.3.6 Reset Register */
+        .reset_reg = {
+            .space_id = AML_AS_SYSTEM_MEMORY,
+            .bit_width = 8,
+            .address = VIRT_GED_REG_ADDR + ACPI_GED_REG_RESET,
+        },
+        .reset_val = ACPI_GED_RESET_VALUE,
+    };
+    *data = fadt;
+}
+
+static void acpi_align_size(GArray *blob, unsigned align)
+{
+    /*
+     * Align size to multiple of given size. This reduces the chance
+     * we need to change size in the future (breaking cross version migration).
+     */
+    g_array_set_size(blob, ROUND_UP(acpi_data_len(blob), align));
+}
+
+/* build FACS */
+static void
+build_facs(GArray *table_data)
+{
+    const char *sig = "FACS";
+    const uint8_t reserved[40] = {};
+
+    g_array_append_vals(table_data, sig, 4); /* Signature */
+    build_append_int_noprefix(table_data, 64, 4); /* Length */
+    build_append_int_noprefix(table_data, 0, 4); /* Hardware Signature */
+    build_append_int_noprefix(table_data, 0, 4); /* Firmware Waking Vector */
+    build_append_int_noprefix(table_data, 0, 4); /* Global Lock */
+    build_append_int_noprefix(table_data, 0, 4); /* Flags */
+    g_array_append_vals(table_data, reserved, 40); /* Reserved */
+}
+
+/* build MADT */
+static void
+build_madt(GArray *table_data, BIOSLinker *linker, LoongArchMachineState *lams)
+{
+    MachineState *ms = MACHINE(lams);
+    int i;
+    AcpiTable table = { .sig = "APIC", .rev = 1, .oem_id = lams->oem_id,
+                        .oem_table_id = lams->oem_table_id };
+
+    acpi_table_begin(&table, table_data);
+
+    /* Local APIC Address */
+    build_append_int_noprefix(table_data, 0, 4);
+    build_append_int_noprefix(table_data, 1 /* PCAT_COMPAT */, 4); /* Flags */
+
+    for (i = 0; i < ms->smp.cpus; i++) {
+        /* Processor Core Interrupt Controller Structure */
+        build_append_int_noprefix(table_data, 17, 1);    /* Type */
+        build_append_int_noprefix(table_data, 15, 1);    /* Length */
+        build_append_int_noprefix(table_data, 1, 1);     /* Version */
+        build_append_int_noprefix(table_data, i + 1, 4); /* ACPI Processor ID */
+        build_append_int_noprefix(table_data, i, 4);     /* Core ID */
+        build_append_int_noprefix(table_data, 1, 4);     /* Flags */
+    }
+
+    /* Extend I/O Interrupt Controller Structure */
+    build_append_int_noprefix(table_data, 20, 1);        /* Type */
+    build_append_int_noprefix(table_data, 13, 1);        /* Length */
+    build_append_int_noprefix(table_data, 1, 1);         /* Version */
+    build_append_int_noprefix(table_data, 3, 1);         /* Cascade */
+    build_append_int_noprefix(table_data, 0, 1);         /* Node */
+    build_append_int_noprefix(table_data, 0xffff, 8);    /* Node map */
+
+    /* MSI Interrupt Controller Structure */
+    build_append_int_noprefix(table_data, 21, 1);        /* Type */
+    build_append_int_noprefix(table_data, 19, 1);        /* Length */
+    build_append_int_noprefix(table_data, 1, 1);         /* Version */
+    build_append_int_noprefix(table_data, LS7A_PCH_MSI_ADDR_LOW, 8);/* Address */
+    build_append_int_noprefix(table_data, 0x40, 4);      /* Start */
+    build_append_int_noprefix(table_data, 0xc0, 4);      /* Count */
+
+    /* Bridge I/O Interrupt Controller Structure */
+    build_append_int_noprefix(table_data, 22, 1);        /* Type */
+    build_append_int_noprefix(table_data, 17, 1);        /* Length */
+    build_append_int_noprefix(table_data, 1, 1);         /* Version */
+    build_append_int_noprefix(table_data, LS7A_PCH_REG_BASE, 8);/* Address */
+    build_append_int_noprefix(table_data, 0x1000, 2);    /* Size */
+    build_append_int_noprefix(table_data, 0, 2);         /* Id */
+    build_append_int_noprefix(table_data, 0x40, 2);      /* Base */
+
+    acpi_table_end(linker, &table);
+}
+
+/* build SRAT */
+static void
+build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
+{
+    uint64_t i;
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(machine);
+    MachineState *ms = MACHINE(lams);
+    AcpiTable table = { .sig = "SRAT", .rev = 1, .oem_id = lams->oem_id,
+                        .oem_table_id = lams->oem_table_id };
+
+    acpi_table_begin(&table, table_data);
+    build_append_int_noprefix(table_data, 1, 4); /* Reserved */
+    build_append_int_noprefix(table_data, 0, 8); /* Reserved */
+
+    for (i = 0; i < ms->smp.cpus; ++i) {
+        /* Processor Local APIC/SAPIC Affinity Structure */
+        build_append_int_noprefix(table_data, 0, 1);  /* Type  */
+        build_append_int_noprefix(table_data, 16, 1); /* Length */
+        /* Proximity Domain [7:0] */
+        build_append_int_noprefix(table_data, 0, 1);
+        build_append_int_noprefix(table_data, i, 1); /* APIC ID */
+        /* Flags, Table 5-36 */
+        build_append_int_noprefix(table_data, 1, 4);
+        build_append_int_noprefix(table_data, 0, 1); /* Local SAPIC EID */
+        /* Proximity Domain [31:8] */
+        build_append_int_noprefix(table_data, 0, 3);
+        build_append_int_noprefix(table_data, 0, 4); /* Reserved */
+    }
+
+    build_srat_memory(table_data, VIRT_LOWMEM_BASE, VIRT_LOWMEM_SIZE,
+                      0, MEM_AFFINITY_ENABLED);
+
+    build_srat_memory(table_data, VIRT_HIGHMEM_BASE, machine->ram_size - VIRT_LOWMEM_SIZE,
+                      0, MEM_AFFINITY_ENABLED);
+
+    acpi_table_end(linker, &table);
+}
+
+typedef
+struct AcpiBuildState {
+    /* Copy of table in RAM (for patching). */
+    MemoryRegion *table_mr;
+    /* Is table patched? */
+    uint8_t patched;
+    void *rsdp;
+    MemoryRegion *rsdp_mr;
+    MemoryRegion *linker_mr;
+} AcpiBuildState;
+
+static void build_gpex_pci0_int(Aml *table)
+{
+    Aml *sb_scope = aml_scope("_SB");
+    Aml *pci0_scope = aml_scope("PCI0");
+    Aml *prt_pkg = aml_varpackage(128);
+    int slot, pin;
+
+    for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
+        for (pin = 0; pin < PCI_NUM_PINS; pin++) {
+            Aml *pkg = aml_package(4);
+            aml_append(pkg, aml_int((slot << 16) | 0xFFFF));
+            aml_append(pkg, aml_int(pin));
+            aml_append(pkg, aml_int(0));
+            aml_append(pkg, aml_int(80 + (slot + pin) % 4));
+            aml_append(prt_pkg, pkg);
+        }
+    }
+    aml_append(pci0_scope, aml_name_decl("_PRT", prt_pkg));
+    aml_append(sb_scope, pci0_scope);
+    aml_append(table, sb_scope);
+}
+
+static void build_dbg_aml(Aml *table)
+{
+    Aml *field;
+    Aml *method;
+    Aml *while_ctx;
+    Aml *scope = aml_scope("\\");
+    Aml *buf = aml_local(0);
+    Aml *len = aml_local(1);
+    Aml *idx = aml_local(2);
+
+    aml_append(scope,
+       aml_operation_region("DBG", AML_SYSTEM_IO, aml_int(0x0402), 0x01));
+    field = aml_field("DBG", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
+    aml_append(field, aml_named_field("DBGB", 8));
+    aml_append(scope, field);
+
+    method = aml_method("DBUG", 1, AML_NOTSERIALIZED);
+
+    aml_append(method, aml_to_hexstring(aml_arg(0), buf));
+    aml_append(method, aml_to_buffer(buf, buf));
+    aml_append(method, aml_subtract(aml_sizeof(buf), aml_int(1), len));
+    aml_append(method, aml_store(aml_int(0), idx));
+
+    while_ctx = aml_while(aml_lless(idx, len));
+    aml_append(while_ctx,
+        aml_store(aml_derefof(aml_index(buf, idx)), aml_name("DBGB")));
+    aml_append(while_ctx, aml_increment(idx));
+    aml_append(method, while_ctx);
+    aml_append(method, aml_store(aml_int(0x0A), aml_name("DBGB")));
+    aml_append(scope, method);
+    aml_append(table, scope);
+}
+
+static Aml *build_osc_method(void)
+{
+    Aml *if_ctx;
+    Aml *if_ctx2;
+    Aml *else_ctx;
+    Aml *method;
+    Aml *a_cwd1 = aml_name("CDW1");
+    Aml *a_ctrl = aml_local(0);
+
+    method = aml_method("_OSC", 4, AML_NOTSERIALIZED);
+    aml_append(method, aml_create_dword_field(aml_arg(3), aml_int(0), "CDW1"));
+
+    if_ctx = aml_if(aml_equal(
+        aml_arg(0), aml_touuid("33DB4D5B-1FF7-401C-9657-7441C03DD766")));
+    aml_append(if_ctx, aml_create_dword_field(aml_arg(3), aml_int(4), "CDW2"));
+    aml_append(if_ctx, aml_create_dword_field(aml_arg(3), aml_int(8), "CDW3"));
+    aml_append(if_ctx, aml_store(aml_name("CDW3"), a_ctrl));
+
+    /*
+     * Always allow native PME, AER (no dependencies)
+     * Allow SHPC (PCI bridges can have SHPC controller)
+     */
+    aml_append(if_ctx, aml_and(a_ctrl, aml_int(0x1F), a_ctrl));
+
+    if_ctx2 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(1))));
+    /* Unknown revision */
+    aml_append(if_ctx2, aml_or(a_cwd1, aml_int(0x08), a_cwd1));
+    aml_append(if_ctx, if_ctx2);
+
+    if_ctx2 = aml_if(aml_lnot(aml_equal(aml_name("CDW3"), a_ctrl)));
+    /* Capabilities bits were masked */
+    aml_append(if_ctx2, aml_or(a_cwd1, aml_int(0x10), a_cwd1));
+    aml_append(if_ctx, if_ctx2);
+
+    /* Update DWORD3 in the buffer */
+    aml_append(if_ctx, aml_store(a_ctrl, aml_name("CDW3")));
+    aml_append(method, if_ctx);
+
+    else_ctx = aml_else();
+    /* Unrecognized UUID */
+    aml_append(else_ctx, aml_or(a_cwd1, aml_int(4), a_cwd1));
+    aml_append(method, else_ctx);
+
+    aml_append(method, aml_return(aml_arg(3)));
+    return method;
+}
+
+static void build_uart_device_aml(Aml *table)
+{
+    Aml *dev;
+    Aml *crs;
+    Aml *pkg0, *pkg1, *pkg2;
+    uint32_t uart_irq = LS7A_UART_IRQ;
+
+    Aml *scope = aml_scope("_SB");
+    dev = aml_device("COMA");
+    aml_append(dev, aml_name_decl("_HID", aml_string("PNP0501")));
+    aml_append(dev, aml_name_decl("_UID", aml_int(0)));
+    aml_append(dev, aml_name_decl("_CCA", aml_int(1)));
+    crs = aml_resource_template();
+    aml_append(crs,
+        aml_qword_memory(AML_POS_DECODE, AML_MIN_FIXED, AML_MAX_FIXED,
+                         AML_NON_CACHEABLE, AML_READ_WRITE,
+                         0, 0x1FE001E0, 0x1FE001E7, 0, 0x8));
+    aml_append(crs, aml_interrupt(AML_CONSUMER, AML_LEVEL, AML_ACTIVE_HIGH,
+                                  AML_SHARED, &uart_irq, 1));
+    aml_append(dev, aml_name_decl("_CRS", crs));
+    pkg0 = aml_package(0x2);
+    aml_append(pkg0, aml_int(0x05F5E100));
+    aml_append(pkg0, aml_string("clock-frenquency"));
+    pkg1 = aml_package(0x1);
+    aml_append(pkg1, pkg0);
+    pkg2 = aml_package(0x2);
+    aml_append(pkg2, aml_touuid("DAFFD814-6EBA-4D8C-8A91-BC9BBF4AA301"));
+    aml_append(pkg2, pkg1);
+    aml_append(dev, aml_name_decl("_DSD", pkg2));
+    aml_append(scope, dev);
+    aml_append(table, scope);
+}
+
+/* build DSDT */
+static void
+build_dsdt(GArray *table_data, BIOSLinker *linker, MachineState *machine)
+{
+    Aml *dsdt, *sb_scope, *scope, *dev, *crs, *pkg;
+    int root_bus_limit = 0x7F;
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(machine);
+    AcpiTable table = { .sig = "DSDT", .rev = 1, .oem_id = lams->oem_id,
+                        .oem_table_id = lams->oem_table_id };
+
+    acpi_table_begin(&table, table_data);
+
+    dsdt = init_aml_allocator();
+
+    build_dbg_aml(dsdt);
+
+    sb_scope = aml_scope("_SB");
+    dev = aml_device("PCI0");
+    aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0A08")));
+    aml_append(dev, aml_name_decl("_CID", aml_eisaid("PNP0A03")));
+    aml_append(dev, aml_name_decl("_ADR", aml_int(0)));
+    aml_append(dev, aml_name_decl("_BBN", aml_int(0)));
+    aml_append(dev, aml_name_decl("_UID", aml_int(1)));
+    aml_append(dev, build_osc_method());
+    aml_append(sb_scope, dev);
+    aml_append(dsdt, sb_scope);
+
+    build_gpex_pci0_int(dsdt);
+    build_uart_device_aml(dsdt);
+    if (lams->acpi_ged) {
+        build_ged_aml(dsdt, "\\_SB."GED_DEVICE,
+                      HOTPLUG_HANDLER(lams->acpi_ged),
+                      LS7A_SCI_IRQ - PCH_PIC_IRQ_OFFSET, AML_SYSTEM_MEMORY,
+                      VIRT_GED_EVT_ADDR);
+    }
+
+    scope = aml_scope("\\_SB.PCI0");
+    /* Build PCI0._CRS */
+    crs = aml_resource_template();
+    aml_append(crs,
+        aml_word_bus_number(AML_MIN_FIXED, AML_MAX_FIXED, AML_POS_DECODE,
+                            0x0000, 0x0, root_bus_limit,
+                            0x0000, root_bus_limit + 1));
+    aml_append(crs,
+        aml_dword_io(AML_MIN_FIXED, AML_MAX_FIXED,
+                    AML_POS_DECODE, AML_ENTIRE_RANGE,
+                    0x0000, 0x0000, 0xFFFF, 0x18000000, 0x10000));
+    aml_append(crs,
+        aml_dword_memory(AML_POS_DECODE, AML_MIN_FIXED, AML_MAX_FIXED,
+                         AML_CACHEABLE, AML_READ_WRITE,
+                         0, LS7A_PCI_MEM_BASE,
+                         LS7A_PCI_MEM_BASE + LS7A_PCI_MEM_SIZE - 1,
+                         0, LS7A_PCI_MEM_BASE));
+    aml_append(scope, aml_name_decl("_CRS", crs));
+    aml_append(dsdt, scope);
+
+    /* System State Package */
+    scope = aml_scope("\\");
+    pkg = aml_package(4);
+    aml_append(pkg, aml_int(ACPI_GED_SLP_TYP_S5));
+    aml_append(pkg, aml_int(0)); /* ignored */
+    aml_append(pkg, aml_int(0)); /* reserved */
+    aml_append(pkg, aml_int(0)); /* reserved */
+    aml_append(scope, aml_name_decl("_S5", pkg));
+    aml_append(dsdt, scope);
+    /* Copy AML table into ACPI tables blob and patch header there */
+    g_array_append_vals(table_data, dsdt->buf->data, dsdt->buf->len);
+    acpi_table_end(linker, &table);
+    free_aml_allocator();
+}
+
+static void acpi_build(AcpiBuildTables *tables, MachineState *machine)
+{
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(machine);
+    GArray *table_offsets;
+    AcpiFadtData fadt_data;
+    unsigned facs, rsdt, fadt, dsdt;
+    uint8_t *u;
+    size_t aml_len = 0;
+    GArray *tables_blob = tables->table_data;
+
+    init_common_fadt_data(&fadt_data);
+
+    table_offsets = g_array_new(false, true, sizeof(uint32_t));
+    ACPI_BUILD_DPRINTF("init ACPI tables\n");
+
+    bios_linker_loader_alloc(tables->linker,
+                             ACPI_BUILD_TABLE_FILE, tables_blob,
+                             64, false);
+
+    /*
+     * FACS is pointed to by FADT.
+     * We place it first since it's the only table that has alignment
+     * requirements.
+     */
+    facs = tables_blob->len;
+    build_facs(tables_blob);
+
+    /* DSDT is pointed to by FADT */
+    dsdt = tables_blob->len;
+    build_dsdt(tables_blob, tables->linker, machine);
+
+    /*
+     * Count the size of the DSDT, we will need it for
+     * legacy sizing of ACPI tables.
+     */
+    aml_len += tables_blob->len - dsdt;
+
+    /* ACPI tables pointed to by RSDT */
+    fadt = tables_blob->len;
+    acpi_add_table(table_offsets, tables_blob);
+    fadt_data.facs_tbl_offset = &facs;
+    fadt_data.dsdt_tbl_offset = &dsdt;
+    fadt_data.xdsdt_tbl_offset = &dsdt;
+    build_fadt(tables_blob, tables->linker, &fadt_data,
+               lams->oem_id, lams->oem_table_id);
+    aml_len += tables_blob->len - fadt;
+
+    acpi_add_table(table_offsets, tables_blob);
+    build_madt(tables_blob, tables->linker, lams);
+
+    acpi_add_table(table_offsets, tables_blob);
+    build_srat(tables_blob, tables->linker, machine);
+
+    acpi_add_table(table_offsets, tables_blob);
+    {
+        AcpiMcfgInfo mcfg = {
+           .base = cpu_to_le64(LS_PCIECFG_BASE),
+           .size = cpu_to_le64(LS_PCIECFG_SIZE),
+        };
+        build_mcfg(tables_blob, tables->linker, &mcfg, lams->oem_id,
+                   lams->oem_table_id);
+    }
+
+    /* Add tables supplied by user (if any) */
+    for (u = acpi_table_first(); u; u = acpi_table_next(u)) {
+        unsigned len = acpi_table_len(u);
+
+        acpi_add_table(table_offsets, tables_blob);
+        g_array_append_vals(tables_blob, u, len);
+    }
+
+    /* RSDT is pointed to by RSDP */
+    rsdt = tables_blob->len;
+    build_rsdt(tables_blob, tables->linker, table_offsets,
+               lams->oem_id, lams->oem_table_id);
+
+    /* RSDP is in FSEG memory, so allocate it separately */
+    {
+        AcpiRsdpData rsdp_data = {
+            .revision = 0,
+            .oem_id = lams->oem_id,
+            .xsdt_tbl_offset = NULL,
+            .rsdt_tbl_offset = &rsdt,
+        };
+        build_rsdp(tables->rsdp, tables->linker, &rsdp_data);
+    }
+
+    /*
+     * The align size is 128, warn if 64k is not enough therefore
+     * the align size could be resized.
+     */
+    if (tables_blob->len > ACPI_BUILD_TABLE_SIZE / 2) {
+        warn_report("ACPI table size %u exceeds %d bytes,"
+                    " migration may not work",
+                    tables_blob->len, ACPI_BUILD_TABLE_SIZE / 2);
+        error_printf("Try removing CPUs, NUMA nodes, memory slots"
+                     " or PCI bridges.");
+    }
+
+    acpi_align_size(tables->linker->cmd_blob, ACPI_BUILD_ALIGN_SIZE);
+
+    /* Cleanup memory that's no longer used. */
+    g_array_free(table_offsets, true);
+}
+
+static void acpi_ram_update(MemoryRegion *mr, GArray *data)
+{
+    uint32_t size = acpi_data_len(data);
+
+    /*
+     * Make sure RAM size is correct - in case it got changed
+     * e.g. by migration
+     */
+    memory_region_ram_resize(mr, size, &error_abort);
+
+    memcpy(memory_region_get_ram_ptr(mr), data->data, size);
+    memory_region_set_dirty(mr, 0, size);
+}
+
+static void acpi_build_update(void *build_opaque)
+{
+    AcpiBuildState *build_state = build_opaque;
+    AcpiBuildTables tables;
+
+    /* No state to update or already patched? Nothing to do. */
+    if (!build_state || build_state->patched) {
+        return;
+    }
+    build_state->patched = 1;
+
+    acpi_build_tables_init(&tables);
+
+    acpi_build(&tables, MACHINE(qdev_get_machine()));
+
+    acpi_ram_update(build_state->table_mr, tables.table_data);
+    acpi_ram_update(build_state->rsdp_mr, tables.rsdp);
+    acpi_ram_update(build_state->linker_mr, tables.linker->cmd_blob);
+
+    acpi_build_tables_cleanup(&tables, true);
+}
+
+static void acpi_build_reset(void *build_opaque)
+{
+    AcpiBuildState *build_state = build_opaque;
+    build_state->patched = 0;
+}
+
+static const VMStateDescription vmstate_acpi_build = {
+    .name = "acpi_build",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(patched, AcpiBuildState),
+        VMSTATE_END_OF_LIST()
+    },
+};
+
+void loongarch_acpi_setup(LoongArchMachineState *lams)
+{
+    AcpiBuildTables tables;
+    AcpiBuildState *build_state;
+
+    if (!lams->fw_cfg) {
+        ACPI_BUILD_DPRINTF("No fw cfg. Bailing out.\n");
+        return;
+    }
+
+    if (!loongarch_is_acpi_enabled(lams)) {
+        ACPI_BUILD_DPRINTF("ACPI disabled. Bailing out.\n");
+        return;
+    }
+
+    build_state = g_malloc0(sizeof *build_state);
+
+    acpi_build_tables_init(&tables);
+    acpi_build(&tables, MACHINE(lams));
+
+    /* Now expose it all to Guest */
+    build_state->table_mr = acpi_add_rom_blob(acpi_build_update,
+                                              build_state, tables.table_data,
+                                              ACPI_BUILD_TABLE_FILE);
+    assert(build_state->table_mr != NULL);
+
+    build_state->linker_mr =
+        acpi_add_rom_blob(acpi_build_update, build_state,
+                          tables.linker->cmd_blob, ACPI_BUILD_LOADER_FILE);
+
+    build_state->rsdp_mr = acpi_add_rom_blob(acpi_build_update,
+                                             build_state, tables.rsdp,
+                                             ACPI_BUILD_RSDP_FILE);
+
+    qemu_register_reset(acpi_build_reset, build_state);
+    acpi_build_reset(build_state);
+    vmstate_register(NULL, 0, &vmstate_acpi_build, build_state);
+
+    /*
+     * Cleanup tables but don't free the memory: we track it
+     * in build_state.
+     */
+    acpi_build_tables_cleanup(&tables, false);
+}
diff --git a/hw/loongarch/loongson3.c b/hw/loongarch/loongson3.c
index 205894d..3ec8cda 100644
--- a/hw/loongarch/loongson3.c
+++ b/hw/loongarch/loongson3.c
@@ -31,6 +31,10 @@
 #include "hw/loongarch/fw_cfg.h"
 #include "target/loongarch/cpu.h"
 #include "hw/firmware/smbios.h"
+#include "hw/acpi/aml-build.h"
+#include "qapi/qapi-visit-common.h"
+#include "hw/acpi/generic_event_device.h"
+#include "hw/mem/nvdimm.h"
 
 #define PM_BASE 0x10080000
 #define PM_SIZE 0x100
@@ -67,6 +71,7 @@ static void virt_machine_done(Notifier *notifier, void *data)
     LoongArchMachineState *lams = container_of(notifier,
                                         LoongArchMachineState, machine_done);
     virt_build_smbios(lams);
+    loongarch_acpi_setup(lams);
 }
 
 struct memmap_entry {
@@ -95,7 +100,6 @@ static void memmap_add_entry(uint64_t address, uint64_t length, uint32_t type)
     memmap_entries++;
 }
 
-
 /*
  * This is a placeholder for missing ACPI,
  * and will eventually be replaced.
@@ -166,7 +170,32 @@ static int64_t load_kernel_info(void)
     return kernel_entry;
 }
 
-static void loongarch_devices_init(DeviceState *pch_pic)
+static DeviceState *create_acpi_ged(DeviceState *pch_pic, LoongArchMachineState *lams)
+{
+    DeviceState *dev;
+    MachineState *ms = MACHINE(lams);
+    uint32_t event = ACPI_GED_PWR_DOWN_EVT;
+
+    if (ms->ram_slots) {
+        event |= ACPI_GED_MEM_HOTPLUG_EVT;
+    }
+    dev = qdev_new(TYPE_ACPI_GED);
+    qdev_prop_set_uint32(dev, "ged-event", event);
+
+    /* ged event */
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, VIRT_GED_EVT_ADDR);
+    /* memory hotplug */
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 1, VIRT_GED_MEM_ADDR);
+    /* ged regs used for reset and power down */
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 2, VIRT_GED_REG_ADDR);
+
+    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0,
+                       qdev_get_gpio_in(pch_pic, LS7A_SCI_IRQ - PCH_PIC_IRQ_OFFSET));
+    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+    return dev;
+}
+
+static void loongarch_devices_init(DeviceState *pch_pic, LoongArchMachineState *lams)
 {
     DeviceState *gpex_dev;
     SysBusDevice *d;
@@ -242,6 +271,8 @@ static void loongarch_devices_init(DeviceState *pch_pic)
     memory_region_init_io(pm_mem, NULL, &loongarch_virt_pm_ops,
                           NULL, "loongarch_virt_pm", PM_SIZE);
     memory_region_add_subregion(get_system_memory(), PM_BASE, pm_mem);
+    /* acpi ged */
+    lams->acpi_ged = create_acpi_ged(pch_pic, lams);
 }
 
 static void loongarch_irq_init(LoongArchMachineState *lams)
@@ -343,7 +374,7 @@ static void loongarch_irq_init(LoongArchMachineState *lams)
                               qdev_get_gpio_in(extioi, i + PCH_MSI_IRQ_START));
     }
 
-    loongarch_devices_init(pch_pic);
+    loongarch_devices_init(pch_pic, lams);
 }
 
 static void loongarch_firmware_init(LoongArchMachineState *lams)
@@ -550,6 +581,40 @@ static void loongarch_init(MachineState *machine)
     qemu_add_machine_init_done_notifier(&lams->machine_done);
 }
 
+bool loongarch_is_acpi_enabled(LoongArchMachineState *lams)
+{
+    if (lams->acpi == ON_OFF_AUTO_OFF) {
+        return false;
+    }
+    return true;
+}
+
+static void loongarch_get_acpi(Object *obj, Visitor *v, const char *name,
+                               void *opaque, Error **errp)
+{
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(obj);
+    OnOffAuto acpi = lams->acpi;
+
+    visit_type_OnOffAuto(v, name, &acpi, errp);
+}
+
+static void loongarch_set_acpi(Object *obj, Visitor *v, const char *name,
+                               void *opaque, Error **errp)
+{
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(obj);
+
+    visit_type_OnOffAuto(v, name, &lams->acpi, errp);
+}
+
+static void loongarch_machine_initfn(Object *obj)
+{
+    LoongArchMachineState *lams = LOONGARCH_MACHINE(obj);
+
+    lams->acpi = ON_OFF_AUTO_AUTO;
+    lams->oem_id = g_strndup(ACPI_BUILD_APPNAME6, 6);
+    lams->oem_table_id = g_strndup(ACPI_BUILD_APPNAME8, 8);
+}
+
 static void loongarch_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
@@ -565,6 +630,12 @@ static void loongarch_class_init(ObjectClass *oc, void *data)
     mc->block_default_type = IF_VIRTIO;
     mc->default_boot_order = "c";
     mc->no_cdrom = 1;
+
+    object_class_property_add(oc, "acpi", "OnOffAuto",
+        loongarch_get_acpi, loongarch_set_acpi,
+        NULL, NULL);
+    object_class_property_set_description(oc, "acpi",
+        "Enable ACPI");
 }
 
 static const TypeInfo loongarch_machine_types[] = {
@@ -573,6 +644,7 @@ static const TypeInfo loongarch_machine_types[] = {
         .parent         = TYPE_MACHINE,
         .instance_size  = sizeof(LoongArchMachineState),
         .class_init     = loongarch_class_init,
+        .instance_init = loongarch_machine_initfn,
     }
 };
 
diff --git a/hw/loongarch/meson.build b/hw/loongarch/meson.build
index 81131c9..3e7cbcf 100644
--- a/hw/loongarch/meson.build
+++ b/hw/loongarch/meson.build
@@ -3,5 +3,6 @@ loongarch_ss.add(files(
     'fw_cfg.c',
 ))
 loongarch_ss.add(when: 'CONFIG_LOONGARCH_VIRT', if_true: files('loongson3.c'))
+loongarch_ss.add(when: 'CONFIG_ACPI', if_true: files('acpi-build.c'))
 
 hw_arch += {'loongarch': loongarch_ss}