run: pass Ctrl+C to GDB when using -D

README.adoc

@@ -3326,11 +3326,11 @@ qemu-arm -g 1234 -L . bin/ls
 
 TODO: find source. Lazy now.
 
-=== Debug QEMU
+=== Debug the emulator
 
-When you start interacting with QEMU hardware, it is useful to see what is going on inside of QEMU itself.
+When you start hacking QEMU or gem5, it is useful to see what is going on inside the emulator themselves.
 
-This is of course trivial since QEMU is just an userland program on the host, but we make it a bit easier with:
+This is of course trivial since they are just regular userland programs on the host, but we make it a bit easier with:
 
 ....
 ./run -D
@@ -3349,7 +3349,13 @@ And in QEMU:
 /pci.sh
 ....
 
-Just make sure that you never click inside the QEMU window when doing that, otherwise you mouse gets captured forever, and the only solution I can find is to go to a TTY with `Ctrl-Alt-F1` and `kill` QEMU.
+When in <<graphic-mode,non graphic mode>>, using `-D` makes Ctrl-C not get passed to the QEMU guest anymore: it is instead captured by GDB itself, so allow breaking. So e.g. you won't be able to easily quit from a guest progra like:
+
+....
+sleep 10
+....
+
+In graphic mode, make sure that you never click inside the QEMU graphic while debugging, otherwise you mouse gets captured forever, and the only solution I can find is to go to a TTY with `Ctrl-Alt-F1` and `kill` QEMU.
 
 You can still send key presses to QEMU however even without the mouse capture, just either click on the title bar, or alt tab to give it focus.
 

run

@@ -195,6 +195,12 @@ ${extra_flags} \
 "
   fi
 else
+  if [ -z "$debug_vm" ]; then
+    serial_monitor='-serial mon:stdio \
+'
+  else
+    serial_monitor=
+  fi
   if "$kvm"; then
     extra_flags="${extra_flags} -enable-kvm"
   fi
@@ -205,9 +211,9 @@ ${debug_vm} \
 -device rtl8139,netdev=net0 \\
 -gdb tcp::1234 \\
 -m '${memory}' \\
--serial mon:stdio \\
 -monitor telnet::45454,server,nowait \\
 -netdev user,hostfwd=tcp::45455-:45455,hostfwd=tcp::45456-:22,id=net0 \\
+${serial_monitor} \
 -smp '${cpus}' \\
 -trace 'enable=${trace_type},file=${qemu_out_dir}/trace.bin' \\
 -virtfs 'local,path=${p9_dir},mount_tag=host_scratch,security_model=mapped,id=host_scratch' \\