Re: [PATCH] mos6522: update counters when timer interrupts are off

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 11/25/19 3:14 PM, Laurent Vivier wrote:
> Even if the interrupts are off, counters must be updated because
> they are running anyway and kernel can try to read them
> (it's the case with g3beige kernel).
> 
> Reported-by: Andrew Randrianasulu <randrianasulu@gmail.com>
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>   hw/misc/mos6522.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/misc/mos6522.c b/hw/misc/mos6522.c
> index aa3bfe1afd..cecf0be59e 100644
> --- a/hw/misc/mos6522.c
> +++ b/hw/misc/mos6522.c
> @@ -113,6 +113,10 @@ static int64_t get_next_irq_time(MOS6522State *s, MOS6522Timer *ti,
>       int64_t d, next_time;
>       unsigned int counter;
>   

Can you add a comment here such "Clock disabled. This is the longest 
time before expiration" or better?

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> +    if (ti->frequency == 0) {
> +        return INT64_MAX;
> +    }
> +
>       /* current counter value */
>       d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
>                    ti->frequency, NANOSECONDS_PER_SECOND);
> @@ -149,10 +153,10 @@ static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
>       if (!ti->timer) {
>           return;
>       }
> +    ti->next_irq_time = get_next_irq_time(s, ti, current_time);
>       if ((s->ier & T1_INT) == 0 || (s->acr & T1MODE) != T1MODE_CONT) {
>           timer_del(ti->timer);
>       } else {
> -        ti->next_irq_time = get_next_irq_time(s, ti, current_time);
>           timer_mod(ti->timer, ti->next_irq_time);
>       }
>   }
> @@ -163,10 +167,10 @@ static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
>       if (!ti->timer) {
>           return;
>       }
> +    ti->next_irq_time = get_next_irq_time(s, ti, current_time);
>       if ((s->ier & T2_INT) == 0) {
>           timer_del(ti->timer);
>       } else {
> -        ti->next_irq_time = get_next_irq_time(s, ti, current_time);
>           timer_mod(ti->timer, ti->next_irq_time);
>       }
>   }
>