Re: [PATCH v2 2/4] target/riscv: Apply modularized matching conditions for breakpoint

[Alistair Francis]

On Fri, Feb 23, 2024 at 12:22 PM Alvin Chang via <qemu-devel@nongnu.org> wrote:
>
> We have implemented trigger_common_match(), which checks if the enabled
> privilege levels of the trigger match CPU's current privilege level.
> Remove the related code in riscv_cpu_debug_check_breakpoint() and invoke
> trigger_common_match() to check the privilege levels of the type 2 and
> type 6 triggers for the breakpoints.
>
> This commit also changes the behavior of looping the triggers. In
> previous implementation, if we have a type 2 trigger and
> env->virt_enabled is true, we directly return false to stop the loop.
> Now we keep looping all the triggers until we find a matched trigger.
>
> Only the execution bit and the executed PC should be futher checked in
> riscv_cpu_debug_check_breakpoint().
>
> Signed-off-by: Alvin Chang <alvinga@andestech.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/debug.c | 26 ++++++--------------------
>  1 file changed, 6 insertions(+), 20 deletions(-)
>
> diff --git a/target/riscv/debug.c b/target/riscv/debug.c
> index 3891236b82..b7b0fa8945 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -855,21 +855,17 @@ bool riscv_cpu_debug_check_breakpoint(CPUState *cs)
>          for (i = 0; i < RV_MAX_TRIGGERS; i++) {
>              trigger_type = get_trigger_type(env, i);
>
> +            if (!trigger_common_match(env, trigger_type, i)) {
> +                continue;
> +            }
> +
>              switch (trigger_type) {
>              case TRIGGER_TYPE_AD_MATCH:
> -                /* type 2 trigger cannot be fired in VU/VS mode */
> -                if (env->virt_enabled) {
> -                    return false;
> -                }
> -
>                  ctrl = env->tdata1[i];
>                  pc = env->tdata2[i];
>
>                  if ((ctrl & TYPE2_EXEC) && (bp->pc == pc)) {
> -                    /* check U/S/M bit against current privilege level */
> -                    if ((ctrl >> 3) & BIT(env->priv)) {
> -                        return true;
> -                    }
> +                    return true;
>                  }
>                  break;
>              case TRIGGER_TYPE_AD_MATCH6:
> @@ -877,17 +873,7 @@ bool riscv_cpu_debug_check_breakpoint(CPUState *cs)
>                  pc = env->tdata2[i];
>
>                  if ((ctrl & TYPE6_EXEC) && (bp->pc == pc)) {
> -                    if (env->virt_enabled) {
> -                        /* check VU/VS bit against current privilege level */
> -                        if ((ctrl >> 23) & BIT(env->priv)) {
> -                            return true;
> -                        }
> -                    } else {
> -                        /* check U/S/M bit against current privilege level */
> -                        if ((ctrl >> 3) & BIT(env->priv)) {
> -                            return true;
> -                        }
> -                    }
> +                    return true;
>                  }
>                  break;
>              default:
> --
> 2.34.1
>
>