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[PATCH] target/loongarch: Fix [X]VLDI raising exception incorrectly

WANG Rui posted 1 patch 3 months, 1 week ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20250804023206.1306413-1-wangrui@loongson.cn
Maintainers: Song Gao <gaosong@loongson.cn>
target/loongarch/tcg/insn_trans/trans_vec.c.inc | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
[PATCH] target/loongarch: Fix [X]VLDI raising exception incorrectly
Posted by WANG Rui 3 months, 1 week ago 
According to the specification, [X]VLDI should trigger an invalid instruction
exception only when Bit[12] is 1 and Bit[11:8] > 12. This patch fixes an issue
where an exception was incorrectly raised even when Bit[12] was 0.

Test case:

```
    .global main
main:
    vldi    $vr0, 3328
    ret
```

Reported-by: Zhou Qiankang <wszqkzqk@qq.com>
Signed-off-by: WANG Rui <wangrui@loongson.cn>
---
 target/loongarch/tcg/insn_trans/trans_vec.c.inc | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
index 78730029cb..ee10a9ebe1 100644
--- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
+++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
@@ -3585,11 +3585,6 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
     int sel, vece;
     uint64_t value;
 
-    if (!check_valid_vldi_mode(a)) {
-        generate_exception(ctx, EXCCODE_INE);
-        return true;
-    }
-
     if (!check_vec(ctx, oprsz)) {
         return true;
     }
@@ -3597,6 +3592,11 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
     sel = (a->imm >> 12) & 0x1;
 
     if (sel) {
+        if (!check_valid_vldi_mode(a)) {
+            generate_exception(ctx, EXCCODE_INE);
+            return true;
+        }
+
         value = vldi_get_value(ctx, a->imm);
         vece = MO_64;
     } else {
-- 
2.50.1
Re: [PATCH] target/loongarch: Fix [X]VLDI raising exception incorrectly
Posted by WANG Rui 3 months, 1 week ago 
Hi folks,

On Mon, Aug 4, 2025 at 10:31 AM WANG Rui <wangrui@loongson.cn> wrote:
>
> According to the specification, [X]VLDI should trigger an invalid instruction
> exception only when Bit[12] is 1 and Bit[11:8] > 12. This patch fixes an issue
> where an exception was incorrectly raised even when Bit[12] was 0.
>
> Test case:
>
> ```
>     .global main
> main:
>     vldi    $vr0, 3328
>     ret
> ```
>
> Reported-by: Zhou Qiankang <wszqkzqk@qq.com>
> Signed-off-by: WANG Rui <wangrui@loongson.cn>
> ---
>  target/loongarch/tcg/insn_trans/trans_vec.c.inc | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> index 78730029cb..ee10a9ebe1 100644
> --- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> +++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
> @@ -3585,11 +3585,6 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
>      int sel, vece;
>      uint64_t value;
>
> -    if (!check_valid_vldi_mode(a)) {
> -        generate_exception(ctx, EXCCODE_INE);
> -        return true;
> -    }

Should the INE exception be prioritized over the [A]SXD exception in this case?

- Rui

> -
>      if (!check_vec(ctx, oprsz)) {
>          return true;
>      }
> @@ -3597,6 +3592,11 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
>      sel = (a->imm >> 12) & 0x1;
>
>      if (sel) {
> +        if (!check_valid_vldi_mode(a)) {
> +            generate_exception(ctx, EXCCODE_INE);
> +            return true;
> +        }
> +
>          value = vldi_get_value(ctx, a->imm);
>          vece = MO_64;
>      } else {
> --
> 2.50.1
>
Re: [PATCH] target/loongarch: Fix [X]VLDI raising exception incorrectly
Posted by gaosong 3 months, 1 week ago 
在 2025/8/4 上午11:17, WANG Rui 写道:
> Hi folks,
>
> On Mon, Aug 4, 2025 at 10:31 AM WANG Rui <wangrui@loongson.cn> wrote:
>> According to the specification, [X]VLDI should trigger an invalid instruction
>> exception only when Bit[12] is 1 and Bit[11:8] > 12. This patch fixes an issue
>> where an exception was incorrectly raised even when Bit[12] was 0.
>>
>> Test case:
>>
>> ```
>>      .global main
>> main:
>>      vldi    $vr0, 3328
>>      ret
>> ```
>>
>> Reported-by: Zhou Qiankang <wszqkzqk@qq.com>
>> Signed-off-by: WANG Rui <wangrui@loongson.cn>
>> ---
>>   target/loongarch/tcg/insn_trans/trans_vec.c.inc | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/target/loongarch/tcg/insn_trans/trans_vec.c.inc b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
>> index 78730029cb..ee10a9ebe1 100644
>> --- a/target/loongarch/tcg/insn_trans/trans_vec.c.inc
>> +++ b/target/loongarch/tcg/insn_trans/trans_vec.c.inc
>> @@ -3585,11 +3585,6 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
>>       int sel, vece;
>>       uint64_t value;
>>
>> -    if (!check_valid_vldi_mode(a)) {
>> -        generate_exception(ctx, EXCCODE_INE);
>> -        return true;
>> -    }
> Should the INE exception be prioritized over the [A]SXD exception in this case?
yes, I think we should. this is like ARM.
As Richiard said 'For Arm, at least, decode errors take precedence over 
disabled functional units.'

Thanks.
Song Gao
> - Rui
>
>> -
>>       if (!check_vec(ctx, oprsz)) {
>>           return true;
>>       }
>> @@ -3597,6 +3592,11 @@ static bool gen_vldi(DisasContext *ctx, arg_vldi *a, uint32_t oprsz)
>>       sel = (a->imm >> 12) & 0x1;
>>
>>       if (sel) {
>> +        if (!check_valid_vldi_mode(a)) {
>> +            generate_exception(ctx, EXCCODE_INE);
>> +            return true;
>> +        }
>> +
>>           value = vldi_get_value(ctx, a->imm);
>>           vece = MO_64;
>>       } else {
>> --
>> 2.50.1
>>

Patchew 2.1-devel-b67e4c2

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