qemu-system-riscv64 can't break by gdb
Description of problem:
The qemu-system-riscv64 can't break by gdb.  
( => The target is not responding to interrupt requests.  
Stop debugging it? (y or n) Quit)  

I using old qemu-system-risc64(7.2) don't has this issue.  

This test case running simple OS(riscv-xv6).
Steps to reproduce:
1.qemu-system-riscv64 -machine virt -bios none -kernel kernel/kernel -m 128M -smp 3 -nographic -global   virtio-mmio.force-legacy=false -drive file=fs.img,if=none,format=raw,id=x0 -device virtio-blk-  device,drive=x0,bus=virtio-mmio-bus.0 -S -gdb tcp::26000  
  
  
2.test@test-VirtualBox:~$ riscv64-unknown-linux-gnu-gdb -q                                                                                                                                                 
(gdb) target remote :26000  
Remote debugging using :26000  
warning: No executable has been specified and target does not support  
determining executable automatically.  Try using the "file" command.  
0x0000000000001000 in ?? ()  
(gdb) c  
Continuing.  

3.check xv6 is running.  
xv6 kernel is booting  

hart 2 starting  
hart 1 starting  
init: starting sh  
$  

4.Can't stop by GDB.  
(gdb) c  
Continuing.  
^C^CThe target is not responding to interrupt requests.  
Stop debugging it? (y or n) Quit  
(gdb)
Additional information:
Test on new QEMU.  

```
commit cab35c73be9d579db105ef73fa8a60728a890098 (HEAD -> master, origin/staging, origin/master, origin/HEAD)
Merge: 48ab886d3d d7ee93e243
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Tue Jun 20 10:26:53 2023 +0200
```