hw/char: riscv_htif: replace exit calls with proper shutdown

This replaces the exit calls by shutdown requests, ensuring a proper
cleanup of Qemu. Otherwise, some connections like gdb could be broken
before its final packet ("Wxx") is being sent. This part, being done
inside qemu_cleanup function, can be reached only when the main loop
exits after a shutdown request.

Signed-off-by: Clément Chigot <chigot@adacore.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20231003071427.188697-5-chigot@adacore.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/char/riscv_htif.c

@@ -32,6 +32,7 @@
 #include "exec/address-spaces.h"
 #include "exec/tswap.h"
 #include "sysemu/dma.h"
+#include "sysemu/runstate.h"
 
 #define RISCV_DEBUG_HTIF 0
 #define HTIF_DEBUG(fmt, ...)                                                   \
@@ -206,7 +207,9 @@ static void htif_handle_tohost_write(HTIFState *s, uint64_t val_written)
                     g_free(sig_data);
                 }
 
-                exit(exit_code);
+                qemu_system_shutdown_request_with_code(
+                    SHUTDOWN_CAUSE_GUEST_SHUTDOWN, exit_code);
+                return;
             } else {
                 uint64_t syscall[8];
                 cpu_physical_memory_read(payload, syscall, sizeof(syscall));