target/avr: Disable interrupts when env->skip set

This bit is not saved across interrupts, so we must
delay delivering the interrupt until the skip has
been processed.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1118
Reviewed-by: Michael Rolnik <mrolnik@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/target/avr/helper.c b/target/avr/helper.c
index 34f1cbffb2..156dde4e92 100644
--- a/target/avr/helper.c
+++ b/target/avr/helper.c
@@ -31,6 +31,15 @@ bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
     AVRCPU *cpu = AVR_CPU(cs);
     CPUAVRState *env = &cpu->env;
 
+    /*
+     * We cannot separate a skip from the next instruction,
+     * as the skip would not be preserved across the interrupt.
+     * Separating the two insn normally only happens at page boundaries.
+     */
+    if (env->skip) {
+        return false;
+    }
+
     if (interrupt_request & CPU_INTERRUPT_RESET) {
         if (cpu_interrupts_enabled(env)) {
             cs->exception_index = EXCP_RESET;