Re: [Qemu-devel] [PATCH v1 09/12] target-arm: powerctl: Enable HVC when starting CPUs to EL2

[Peter Maydell]

On 3 October 2018 at 16:07, Edgar E. Iglesias <address@hidden> wrote:
> From: "Edgar E. Iglesias" <address@hidden>
>
> When QEMU provides the equivalent of the EL3 firmware, we
> need to enable HVCs in scr_el3 when turning on CPUs that
> target EL2.
>
> Signed-off-by: Edgar E. Iglesias <address@hidden>
> ---
>  target/arm/arm-powerctl.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/target/arm/arm-powerctl.c b/target/arm/arm-powerctl.c
> index ce55eeb..54f2974 100644
> --- a/target/arm/arm-powerctl.c
> +++ b/target/arm/arm-powerctl.c
> @@ -63,6 +63,7 @@ static void arm_set_cpu_on_async_work(CPUState 
> *target_cpu_state,
>      struct CpuOnInfo *info = (struct CpuOnInfo *) data.host_ptr;
>
>      /* Initialize the cpu we are turning on */
> +    qemu_log("CPU%d reset\n", target_cpu_state->cpu_index);

qemu_log logging should always be masked to a particular
log kind (either via qemu_log_mask() or by explicit check on
the log level). If this was accidentally left-in debug, you could
just drop it :-)

>      cpu_reset(target_cpu_state);
>      target_cpu_state->halted = 0;
>
> @@ -103,6 +104,16 @@ static void arm_set_cpu_on_async_work(CPUState 
> *target_cpu_state,
>      } else {
>          /* Processor is not in secure mode */
>          target_cpu->env.cp15.scr_el3 |= SCR_NS;
> +
> +        /*
> +         * If QEMU is providing the equivalent of EL3 firmware, then we need
> +         * to make sure a CPU targeting EL2 comes out of reset with a
> +         * functional HVC insn.
> +         */
> +        if (arm_feature(&target_cpu->env, ARM_FEATURE_EL3)
> +            && info->target_el == 2) {
> +            target_cpu->env.cp15.scr_el3 |= SCR_HCE;
> +        }
>      }

Otherwise
Reviewed-by: Peter Maydell <address@hidden>
This is definitely required for PSCI and I think it makes sense
in other cases that end up in this powerctl code with EL3 set.

thanks
-- PMM