diff mbox series

[3/6] target/riscv: Correct SXL return value for RV32 in RV64 QEMU

Message ID 20240701033722.954-4-zhiwei_liu@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series target/riscv: Expose RV32 cpu to RV64 QEMU | expand

Commit Message

LIU Zhiwei July 1, 2024, 3:37 a.m. UTC
From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>

Ensure that riscv_cpu_sxl returns MXL_RV32 when runningRV32 in an
RV64 QEMU.

Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
Fixes: 05e6ca5e156 ("target/riscv: Ignore reserved bits in PTE for RV64")
Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
---
 target/riscv/cpu.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comments

Philippe Mathieu-Daudé July 1, 2024, 3:10 p.m. UTC | #1
Hi Tiancheng, Zhiwei,

On 1/7/24 05:37, LIU Zhiwei wrote:
> From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
> 
> Ensure that riscv_cpu_sxl returns MXL_RV32 when runningRV32 in an
> RV64 QEMU.
> 
> Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
> Fixes: 05e6ca5e156 ("target/riscv: Ignore reserved bits in PTE for RV64")
> Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
> ---
>   target/riscv/cpu.h | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 6fe0d712b4..36a712044a 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -668,8 +668,11 @@ static inline RISCVMXL riscv_cpu_sxl(CPURISCVState *env)
>   #ifdef CONFIG_USER_ONLY
>       return env->misa_mxl;
>   #else
> -    return get_field(env->mstatus, MSTATUS64_SXL);
> +    if (env->misa_mxl != MXL_RV32) {
> +        return get_field(env->mstatus, MSTATUS64_SXL);
> +    }
>   #endif
> +    return MXL_RV32;

Can we simplify the previous TARGET_RISCV32 ifdef'ry?

>   }
>   #endif
>
LIU Zhiwei July 2, 2024, 1:48 a.m. UTC | #2
On 2024/7/1 23:10, Philippe Mathieu-Daudé wrote:
> Hi Tiancheng, Zhiwei,
>
> On 1/7/24 05:37, LIU Zhiwei wrote:
>> From: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
>>
>> Ensure that riscv_cpu_sxl returns MXL_RV32 when runningRV32 in an
>> RV64 QEMU.
>>
>> Signed-off-by: TANG Tiancheng <tangtiancheng.ttc@alibaba-inc.com>
>> Fixes: 05e6ca5e156 ("target/riscv: Ignore reserved bits in PTE for 
>> RV64")
>> Reviewed-by: Liu Zhiwei <zhiwei_liu@linux.alibaba.com>
>> ---
>>   target/riscv/cpu.h | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
>> index 6fe0d712b4..36a712044a 100644
>> --- a/target/riscv/cpu.h
>> +++ b/target/riscv/cpu.h
>> @@ -668,8 +668,11 @@ static inline RISCVMXL 
>> riscv_cpu_sxl(CPURISCVState *env)
>>   #ifdef CONFIG_USER_ONLY
>>       return env->misa_mxl;
>>   #else
>> -    return get_field(env->mstatus, MSTATUS64_SXL);
>> +    if (env->misa_mxl != MXL_RV32) {
>> +        return get_field(env->mstatus, MSTATUS64_SXL);
>> +    }
>>   #endif
>> +    return MXL_RV32;
>
> Can we simplify the previous TARGET_RISCV32 ifdef'ry?

I think you mean the TARGET_RISCV32 macro here:

#ifdef TARGET_RISCV32
#define riscv_cpu_sxl(env)  ((void)(env), MXL_RV32)
#else
static inline RISCVMXL riscv_cpu_sxl(CPURISCVState *env)
{
#ifdef CONFIG_USER_ONLY
     return env->misa_mxl;
#else
     return get_field(env->mstatus, MSTATUS64_SXL);
#endif
}
#endif

I think it is better to keep it here for better performance(as a constant).

If you mean whether we  can simplify all the ifdef TARGET_RISCV32 in 
target/riscv or hw/riscv, IMHO, it depends. I git grep the 
TARGET_RISCV32 from target/riscv:

target/riscv/cpu-param.h:#elif defined(TARGET_RISCV32)

target/riscv/cpu.c:#ifdef TARGET_RISCV32

target/riscv/cpu.c:#if defined(TARGET_RISCV32)

target/riscv/cpu.h:#if defined(TARGET_RISCV32)

target/riscv/cpu.h:#ifdef TARGET_RISCV32

target/riscv/cpu.h:#if defined(TARGET_RISCV32)

target/riscv/cpu.h:#if defined(TARGET_RISCV32)

target/riscv/cpu.h:#ifdef TARGET_RISCV32

target/riscv/insn_trans/trans_rvzacas.c.inc:#ifdef TARGET_RISCV32

target/riscv/kvm/kvm-cpu.c:#if defined(TARGET_RISCV32)

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

target/riscv/translate.c:#ifdef TARGET_RISCV32

One case we can remove the TARGET_RISCV32 is in translate.c.

static void gen_set_fpr_hs(DisasContext *ctx, int reg_num, TCGv_i64 t)

{

     if (!ctx->cfg_ptr->ext_zfinx) {

         tcg_gen_mov_i64(cpu_fpr[reg_num], t);

         return;

     }

     if (reg_num != 0) {

         switch (get_xl(ctx)) {

         case MXL_RV32:

#ifdef TARGET_RISCV32

             tcg_gen_extrl_i64_i32(cpu_gpr[reg_num], t);

             break;

#else

         /* fall through */

         case MXL_RV64:

             tcg_gen_mov_i64(cpu_gpr[reg_num], t);

             break;

#endif

         default:

             g_assert_not_reached();

         }

     }

}

We can simplify this code by tcg_gen_trunc_i64_tl.

One case we can't remove the TARGET_RISCV32 is in cpu.c, where we define 
any or max cpu with the width depending on this macro.
I don't analyze all TARGET_RISCV32 using here.  We will upstream a 
standalone patch for validating all its using later.

Thanks,
Zhiwei

>
>>   }
>>   #endif
diff mbox series

Patch

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 6fe0d712b4..36a712044a 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -668,8 +668,11 @@  static inline RISCVMXL riscv_cpu_sxl(CPURISCVState *env)
 #ifdef CONFIG_USER_ONLY
     return env->misa_mxl;
 #else
-    return get_field(env->mstatus, MSTATUS64_SXL);
+    if (env->misa_mxl != MXL_RV32) {
+        return get_field(env->mstatus, MSTATUS64_SXL);
+    }
 #endif
+    return MXL_RV32;
 }
 #endif