Re: [Qemu-devel] [PATCH v1 for-2.12 2/2] s390x: load_psw() should only exchange the PSW for KVM

[Christian Borntraeger]

On 04/09/2018 01:30 PM, David Hildenbrand wrote:
> Let's simplify it a bit. On some weird circumstances we would have tried
> to recompute watchpoints when running under KVM.
> 
> Signed-off-by: David Hildenbrand <address@hidden>
> ---
>  target/s390x/helper.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/target/s390x/helper.c b/target/s390x/helper.c
> index 615fa24ab9..e8548f340a 100644
> --- a/target/s390x/helper.c
> +++ b/target/s390x/helper.c
> @@ -103,16 +103,18 @@ void load_psw(CPUS390XState *env, uint64_t mask, 
> uint64_t addr)
> 
>      env->psw.addr = addr;
>      env->psw.mask = mask;
> -    if (tcg_enabled()) {
> -        env->cc_op = (mask >> 44) & 3;
> +
> +    /* KVM will handle all WAITs and trigger a WAIT exit on disabled_wait */
> +    if (!tcg_enabled()) {
> +        return;
>      }
> +    env->cc_op = (mask >> 44) & 3;

Do we have any call path were KVM could call load_psw?

> 
>      if ((old_mask ^ mask) & PSW_MASK_PER) {
>          s390_cpu_recompute_watchpoints(CPU(s390_env_get_cpu(env)));
>      }
> 
> -    /* KVM will handle all WAITs and trigger a WAIT exit on disabled_wait */
> -    if (tcg_enabled() && (mask & PSW_MASK_WAIT)) {
> +    if (mask & PSW_MASK_WAIT) {
>          s390_handle_wait(s390_env_get_cpu(env));
>      }
>  }
>