target/riscv: Validate the mode in write_vstvec

[PATCH] target/riscv: Validate the mode in write_vstvec

Posted by Jiayi Li 2 months, 1 week ago

Base on the riscv-privileged spec, vstvec substitutes for the usual stvec.
Therefore, the encoding of the MODE should also be restricted to 0 and 1.

Signed-off-by: Jiayi Li <lijiayi@eswincomputing.com>
---
 target/riscv/csr.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 432c59dc66..f9229d92ab 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -3791,7 +3791,12 @@ static RISCVException read_vstvec(CPURISCVState *env, int csrno,
 static RISCVException write_vstvec(CPURISCVState *env, int csrno,
                                    target_ulong val)
 {
-    env->vstvec = val;
+    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
+    if ((val & 3) < 2) {
+        env->vstvec = val;
+    } else {
+        qemu_log_mask(LOG_UNIMP, "CSR_VSTVEC: reserved mode not supported\n");
+    }
     return RISCV_EXCP_NONE;
 }
 
-- 
2.25.1

Re: [PATCH] target/riscv: Validate the mode in write_vstvec

Posted by Alistair Francis 2 months ago

On Mon, Jul 1, 2024 at 3:42 PM Jiayi Li <lijiayi@eswincomputing.com> wrote:
>
> Base on the riscv-privileged spec, vstvec substitutes for the usual stvec.
> Therefore, the encoding of the MODE should also be restricted to 0 and 1.
>
> Signed-off-by: Jiayi Li <lijiayi@eswincomputing.com>

Thanks!

Applied to riscv-to-apply.next

Alistair

> ---
>  target/riscv/csr.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 432c59dc66..f9229d92ab 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3791,7 +3791,12 @@ static RISCVException read_vstvec(CPURISCVState *env, int csrno,
>  static RISCVException write_vstvec(CPURISCVState *env, int csrno,
>                                     target_ulong val)
>  {
> -    env->vstvec = val;
> +    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
> +    if ((val & 3) < 2) {
> +        env->vstvec = val;
> +    } else {
> +        qemu_log_mask(LOG_UNIMP, "CSR_VSTVEC: reserved mode not supported\n");
> +    }
>      return RISCV_EXCP_NONE;
>  }
>
> --
> 2.25.1
>
>

Re: [PATCH] target/riscv: Validate the mode in write_vstvec

Posted by LIU Zhiwei 2 months ago

On 2024/7/1 10:25, Jiayi Li wrote:
> Base on the riscv-privileged spec, vstvec substitutes for the usual stvec.
> Therefore, the encoding of the MODE should also be restricted to 0 and 1.
>
> Signed-off-by: Jiayi Li <lijiayi@eswincomputing.com>
> ---
>   target/riscv/csr.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 432c59dc66..f9229d92ab 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3791,7 +3791,12 @@ static RISCVException read_vstvec(CPURISCVState *env, int csrno,
>   static RISCVException write_vstvec(CPURISCVState *env, int csrno,
>                                      target_ulong val)
>   {
> -    env->vstvec = val;
> +    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
> +    if ((val & 3) < 2) {
> +        env->vstvec = val;
> +    } else {
> +        qemu_log_mask(LOG_UNIMP, "CSR_VSTVEC: reserved mode not supported\n");
> +    }

By the way,  you can get the all the reviewers mail by checking the 
patch with scripts/getmaintainer.pl.

Otherwise,

Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

Zhiwei

>       return RISCV_EXCP_NONE;
>   }
>

Re: [PATCH] target/riscv: Validate the mode in write_vstvec

Posted by Alistair Francis 2 months ago

On Mon, Jul 1, 2024 at 3:42 PM Jiayi Li <lijiayi@eswincomputing.com> wrote:
>
> Base on the riscv-privileged spec, vstvec substitutes for the usual stvec.
> Therefore, the encoding of the MODE should also be restricted to 0 and 1.
>
> Signed-off-by: Jiayi Li <lijiayi@eswincomputing.com>

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

Alistair

> ---
>  target/riscv/csr.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 432c59dc66..f9229d92ab 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3791,7 +3791,12 @@ static RISCVException read_vstvec(CPURISCVState *env, int csrno,
>  static RISCVException write_vstvec(CPURISCVState *env, int csrno,
>                                     target_ulong val)
>  {
> -    env->vstvec = val;
> +    /* bits [1:0] encode mode; 0 = direct, 1 = vectored, 2 >= reserved */
> +    if ((val & 3) < 2) {
> +        env->vstvec = val;
> +    } else {
> +        qemu_log_mask(LOG_UNIMP, "CSR_VSTVEC: reserved mode not supported\n");
> +    }
>      return RISCV_EXCP_NONE;
>  }
>
> --
> 2.25.1
>
>