Re: [PATCH] target/riscv: rvzicbo: Fixup CBO extension register calculation

[Daniel Henrique Barboza <dbarboza@ventanamicro.com>]

On 5/13/24 23:39, Alistair Francis wrote:
> When running the instruction
> 
> ```
>      cbo.flush 0(x0)
> ```
> 
> QEMU would segfault.
> 
> The issue was in cpu_gpr[a->rs1] as QEMU does not have cpu_gpr[0]
> allocated.
> 
> In order to fix this let's use the existing get_address()
> helper. This also has the benefit of performing pointer mask
> calculations on the address specified in rs1.
> 
> The pointer masking specificiation specifically states:
> 
> """
> Cache Management Operations: All instructions in Zicbom, Zicbop and Zicboz
> """
> 
> So this is the correct behaviour and we previously have been incorrectly
> not masking the address.
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> Reported-by: Fabian Thomas <fabian.thomas@cispa.de>
> Fixes: e05da09b7cfd ("target/riscv: implement Zicbom extension")
> ---

LGTM but I wonder if this is the same fix as this one sent by Phil a month
ago or so:

https://lore.kernel.org/qemu-riscv/20240419110514.69697-1-philmd@linaro.org/
("[PATCH] target/riscv: Use get_address() to get address with Zicbom extensions")


Thanks,

Daniel

>   target/riscv/insn_trans/trans_rvzicbo.c.inc | 16 ++++++++++++----
>   1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/target/riscv/insn_trans/trans_rvzicbo.c.inc b/target/riscv/insn_trans/trans_rvzicbo.c.inc
> index d5d7095903..15711c3140 100644
> --- a/target/riscv/insn_trans/trans_rvzicbo.c.inc
> +++ b/target/riscv/insn_trans/trans_rvzicbo.c.inc
> @@ -31,27 +31,35 @@
>   static bool trans_cbo_clean(DisasContext *ctx, arg_cbo_clean *a)
>   {
>       REQUIRE_ZICBOM(ctx);
> -    gen_helper_cbo_clean_flush(tcg_env, cpu_gpr[a->rs1]);
> +    TCGv src = get_address(ctx, a->rs1, 0);
> +
> +    gen_helper_cbo_clean_flush(tcg_env, src);
>       return true;
>   }
>   
>   static bool trans_cbo_flush(DisasContext *ctx, arg_cbo_flush *a)
>   {
>       REQUIRE_ZICBOM(ctx);
> -    gen_helper_cbo_clean_flush(tcg_env, cpu_gpr[a->rs1]);
> +    TCGv src = get_address(ctx, a->rs1, 0);
> +
> +    gen_helper_cbo_clean_flush(tcg_env, src);
>       return true;
>   }
>   
>   static bool trans_cbo_inval(DisasContext *ctx, arg_cbo_inval *a)
>   {
>       REQUIRE_ZICBOM(ctx);
> -    gen_helper_cbo_inval(tcg_env, cpu_gpr[a->rs1]);
> +    TCGv src = get_address(ctx, a->rs1, 0);
> +
> +    gen_helper_cbo_inval(tcg_env, src);
>       return true;
>   }
>   
>   static bool trans_cbo_zero(DisasContext *ctx, arg_cbo_zero *a)
>   {
>       REQUIRE_ZICBOZ(ctx);
> -    gen_helper_cbo_zero(tcg_env, cpu_gpr[a->rs1]);
> +    TCGv src = get_address(ctx, a->rs1, 0);
> +
> +    gen_helper_cbo_zero(tcg_env, src);
>       return true;
>   }