hw/riscv: implement -bios and -kernel support for the ESP32-C3 to rep…

…lace the ROM binary

hw/riscv/esp32c3.c

@@ -27,6 +27,7 @@
 #include "sysemu/runstate.h"
 #include "sysemu/reset.h"
 #include "net/net.h"
+#include "elf.h"
 #include "hw/misc/esp32c3_reg.h"
 #include "hw/misc/esp32c3_rtc_cntl.h"
 #include "hw/misc/esp32c3_cache.h"
@@ -582,21 +583,47 @@ static void esp32c3_machine_init(MachineState *machine)
         memory_region_add_subregion_overlap(sys_mem, esp32c3_memmap[ESP32C3_MEMREGION_FRAMEBUF].base, &ms->rgb.vram, 0);
     }
 
-    /* Open and load the "bios", which is the ROM binary, also named "first stage bootloader" */
-    char *rom_binary = qemu_find_file(QEMU_FILE_TYPE_BIOS, "esp32c3-rom.bin");
-    if (rom_binary == NULL) {
-        error_report("Error: -bios argument not set, and ROM code binary not found (1)");
-        exit(1);
+
+    const char *bios_filename = NULL;
+
+    if (machine->firmware) {
+        bios_filename = machine->firmware;
     }
 
-    /* Load ROM file at the reset address */
-    int size = load_image_targphys_as(rom_binary, ESP32C3_RESET_ADDRESS, 0x60000, CPU(&ms->soc)->as);
-    if (size < 0) {
-        error_report("Error: could not load ROM binary '%s'", rom_binary);
-        exit(1);
+    if (machine->kernel_filename) {
+        if (bios_filename) {
+            qemu_log("Warning: both -bios and -kernel arguments specified. Only loading the the -kernel file.\n");
+        }
+        bios_filename = machine->kernel_filename;
     }
 
-    g_free(rom_binary);
+    if (bios_filename) {
+        /* Since EspRISCVCPU doens't have a RISCVHartArrayState field, let's bake one on the stack. It will only be
+         * used to get the type of the RISC-V CPU (32 or 64 bits) in `riscv_load_kernel` */
+        RISCVHartArrayState hart = {
+            .harts = &ms->soc.parent_obj,
+            .num_harts = 1,
+        };
+
+        /* On failure, riscv_load_kernel exits the program */
+        riscv_load_kernel(machine, &hart, ESP32C3_RESET_ADDRESS, false, NULL);
+    } else {
+        /* Open and load the "bios", which is the ROM binary, also named "first stage bootloader" */
+        char *rom_binary = qemu_find_file(QEMU_FILE_TYPE_BIOS, "esp32c3-rom.bin");
+        if (rom_binary == NULL) {
+            error_report("Error: -bios argument not set, and ROM code binary not found (1)");
+            exit(1);
+        }
+
+        /* Load ROM file at the reset address */
+        int size = load_image_targphys_as(rom_binary, ESP32C3_RESET_ADDRESS, 0x60000, CPU(&ms->soc)->as);
+        if (size < 0) {
+            error_report("Error: could not load ROM binary '%s'", rom_binary);
+            exit(1);
+        }
+
+        g_free(rom_binary);
+    }
 }