boot.c: delay exiting boot if menu key is ESC

If the menu key is ESC, do not restart boot unless
1.5 seconds have passed.  Otherwise users (trained by years of
repeatedly hitting keys to enter the BIOS) will end up hitting ESC
multiple times and immediately booting the primary boot device.

Suggested-by: Matt DeVillier <matt.devillier@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/boot.c b/src/boot.c
index f23e9e15..3aab8d42 100644
--- a/src/boot.c
+++ b/src/boot.c
@@ -486,9 +486,15 @@ interactive_bootmenu(void)
                , strtcpy(desc, pos->description, ARRAY_SIZE(desc)));
     }
 
-    // Get key press
+    // Get key press.  If the menu key is ESC, do not restart boot unless
+    // 1.5 seconds have passed.  Otherwise users (trained by years of
+    // repeatedly hitting keys to enter the BIOS) will end up hitting ESC
+    // multiple times and immediately booting the primary boot device.
+    int esc_accepted_time = irqtimer_calc(menukey == 1 ? 1500 : 0);
     for (;;) {
         scan_code = get_keystroke(1000);
+        if (scan_code == 1 && !irqtimer_check(esc_accepted_time))
+            continue;
         if (scan_code >= 1 && scan_code <= maxmenu+1)
             break;
     }