Re: [PATCH v4 3/4] target/riscv: Apply modularized matching conditions for watchpoint

[Alistair Francis]

On Tue, Feb 27, 2024 at 11:26 AM 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_watchpoint() and invoke
> trigger_common_match() to check the privilege levels of the type 2 and
> type 6 triggers for the watchpoints.
>
> 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 load/store bits and loaded/stored address should be further checked
> in riscv_cpu_debug_check_watchpoint().
>
> Signed-off-by: Alvin Chang <alvinga@andestech.com>

Acked-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 b7b0fa8945..9f9f332019 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -899,13 +899,12 @@ bool riscv_cpu_debug_check_watchpoint(CPUState *cs, 
> CPUWatchpoint *wp)
>      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];
>              addr = env->tdata2[i];
>              flags = 0;
> @@ -918,10 +917,7 @@ bool riscv_cpu_debug_check_watchpoint(CPUState *cs, 
> CPUWatchpoint *wp)
>              }
>
>              if ((wp->flags & flags) && (wp->vaddr == addr)) {
> -                /* 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:
> @@ -937,17 +933,7 @@ bool riscv_cpu_debug_check_watchpoint(CPUState *cs, 
> CPUWatchpoint *wp)
>              }
>
>              if ((wp->flags & flags) && (wp->vaddr == addr)) {
> -                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
>
>