[3/6] hw/loongarch: Add linux kernel booting support

diff --git a/hw/loongarch/loongson3.c b/hw/loongarch/loongson3.c
index e1056d3e0f..81d87bd129 100644
--- a/hw/loongarch/loongson3.c
+++ b/hw/loongarch/loongson3.c
@@ -109,6 +109,8 @@  static const MemoryRegionOps loongarch_virt_pm_ops = {
 static struct _loaderparams {
     uint64_t ram_size;
     const char *kernel_filename;
+    const char *kernel_cmdline;
+    const char *initrd_filename;
 } loaderparams;
 
 static uint64_t cpu_loongarch_virt_to_phys(void *opaque, uint64_t addr)
@@ -358,18 +360,97 @@  static void reset_load_elf(void *opaque)
     }
 }
 
+/* Load an image file into an fw_cfg entry identified by key. */
+static void load_image_to_fw_cfg(FWCfgState *fw_cfg, uint16_t size_key,
+                                 uint16_t data_key, const char *image_name,
+                                 bool try_decompress)
+{
+    size_t size = -1;
+    uint8_t *data;
+
+    if (image_name == NULL) {
+        return;
+    }
+
+    if (try_decompress) {
+        size = load_image_gzipped_buffer(image_name,
+                                         LOAD_IMAGE_MAX_GUNZIP_BYTES, &data);
+    }
+
+    if (size == (size_t)-1) {
+        gchar *contents;
+        gsize length;
+
+        if (!g_file_get_contents(image_name, &contents, &length, NULL)) {
+            error_report("failed to load \"%s\"", image_name);
+            exit(1);
+        }
+        size = length;
+        data = (uint8_t *)contents;
+    }
+
+    fw_cfg_add_i32(fw_cfg, size_key, size);
+    fw_cfg_add_bytes(fw_cfg, data_key, data, size);
+}
+
+static void fw_cfg_add_kernel_info(FWCfgState *fw_cfg)
+{
+    /*
+     * Expose the kernel, the command line, and the initrd in fw_cfg.
+     * We don't process them here at all, it's all left to the
+     * firmware.
+     */
+    load_image_to_fw_cfg(fw_cfg,
+                         FW_CFG_KERNEL_SIZE, FW_CFG_KERNEL_DATA,
+                         loaderparams.kernel_filename,
+                         false);
+
+    if (loaderparams.initrd_filename) {
+        load_image_to_fw_cfg(fw_cfg,
+                             FW_CFG_INITRD_SIZE, FW_CFG_INITRD_DATA,
+                             loaderparams.initrd_filename, false);
+    }
+
+    if (loaderparams.kernel_cmdline) {
+        fw_cfg_add_i32(fw_cfg, FW_CFG_CMDLINE_SIZE,
+                       strlen(loaderparams.kernel_cmdline) + 1);
+        fw_cfg_add_string(fw_cfg, FW_CFG_CMDLINE_DATA,
+                          loaderparams.kernel_cmdline);
+    }
+}
+
+static void loongarch_firmware_boot(LoongArchMachineState *lams)
+{
+    fw_cfg_add_kernel_info(lams->fw_cfg);
+}
+
+static void loongarch_direct_kernel_boot(LoongArchMachineState *lams)
+{
+    MachineState *machine = MACHINE(lams);
+    int64_t kernel_addr = 0;
+    LoongArchCPU *lacpu;
+    int i;
+
+    kernel_addr = load_kernel_info();
+    if (!machine->firmware) {
+        for (i = 0; i < machine->smp.cpus; i++) {
+            lacpu = LOONGARCH_CPU(qemu_get_cpu(i));
+            lacpu->env.load_elf = true;
+            lacpu->env.elf_address = kernel_addr;
+        }
+    }
+}
+
 static void loongarch_init(MachineState *machine)
 {
+    LoongArchCPU *lacpu;
     const char *cpu_model = machine->cpu_type;
-    const char *kernel_filename = machine->kernel_filename;
     ram_addr_t offset = 0;
     ram_addr_t ram_size = machine->ram_size;
     uint64_t highram_size = 0;
     MemoryRegion *address_space_mem = get_system_memory();
     LoongArchMachineState *lams = LOONGARCH_MACHINE(machine);
-    LoongArchCPU *lacpu;
     int i;
-    int64_t kernel_addr = 0;
 
     if (!cpu_model) {
         cpu_model = LOONGARCH_CPU_TYPE_NAME("la464");
@@ -418,20 +499,23 @@  static void loongarch_init(MachineState *machine)
                         memmap_table,
                         sizeof(struct memmap_entry) * (memmap_entries));
     }
-
-    if (kernel_filename) {
-        loaderparams.ram_size = ram_size;
-        loaderparams.kernel_filename = kernel_filename;
-        kernel_addr = load_kernel_info();
-        if (!machine->firmware) {
-            for (i = 0; i < machine->smp.cpus; i++) {
-                lacpu = LOONGARCH_CPU(qemu_get_cpu(i));
-                lacpu->env.load_elf = true;
-                lacpu->env.elf_address = kernel_addr;
-                qemu_register_reset(reset_load_elf, lacpu);
-            }
+    loaderparams.ram_size = ram_size;
+    loaderparams.kernel_filename = machine->kernel_filename;
+    loaderparams.kernel_cmdline = machine->kernel_cmdline;
+    loaderparams.initrd_filename = machine->initrd_filename;
+    /* load the kernel. */
+    if (loaderparams.kernel_filename) {
+        if (lams->bios_loaded) {
+            loongarch_firmware_boot(lams);
+        } else {
+            loongarch_direct_kernel_boot(lams);
         }
     }
+    /* register reset function */
+    for (i = 0; i < machine->smp.cpus; i++) {
+        lacpu = LOONGARCH_CPU(qemu_get_cpu(i));
+        qemu_register_reset(reset_load_elf, lacpu);
+    }
     /* Initialize the IO interrupt subsystem */
     loongarch_irq_init(lams);
 }