Re: [Qemu-riscv] [Qemu-devel] [PATCH] target/riscv: Do not allow sfence.vma from user mode

[Alistair Francis]

On Mon, Apr 1, 2019 at 1:39 PM Jonathan Behrens <address@hidden> wrote:
>
> The 'sfence.vma' instruction is privileged, and should only ever be allowed
> when executing in supervisor mode or higher.
>
> Jonathan
>
> Signed-off-by: Jonathan Behrens <address@hidden>

Reviewed-by: Alistair Francis <address@hidden>

Alistair

> ---
>  target/riscv/op_helper.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
> index b7dc18a41e..644d0fb35f 100644
> --- a/target/riscv/op_helper.c
> +++ b/target/riscv/op_helper.c
> @@ -145,9 +145,10 @@ void helper_tlb_flush(CPURISCVState *env)
>  {
>      RISCVCPU *cpu = riscv_env_get_cpu(env);
>      CPUState *cs = CPU(cpu);
> -    if (env->priv == PRV_S &&
> -        env->priv_ver >= PRIV_VERSION_1_10_0 &&
> -        get_field(env->mstatus, MSTATUS_TVM)) {
> +    if (!(env->priv >= PRV_S) ||
> +        (env->priv == PRV_S &&
> +         env->priv_ver >= PRIV_VERSION_1_10_0 &&
> +         get_field(env->mstatus, MSTATUS_TVM))) {
>          riscv_raise_exception(env, RISCV_EXCP_ILLEGAL_INST, GETPC());
>      } else {
>          tlb_flush(cs);
> --
> 2.20.1