Re: [PATCH 1/2] linux-user: add sched_getattr support

[Laurent Vivier]

Le 11/12/2021 à 03:27, Tonis Tiigi a écrit :
> Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
> ---
>   linux-user/syscall.c      | 55 +++++++++++++++++++++++++++++++++++++++
>   linux-user/syscall_defs.h | 15 +++++++++++
>   2 files changed, 70 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index f1cfcc8104..670b61b2ef 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -339,6 +339,10 @@ _syscall3(int, sys_sched_getaffinity, pid_t, pid, unsigned 
> int, len,
>   #define __NR_sys_sched_setaffinity __NR_sched_setaffinity
>   _syscall3(int, sys_sched_setaffinity, pid_t, pid, unsigned int, len,
>             unsigned long *, user_mask_ptr);
> +#define __NR_sys_sched_getattr __NR_sched_getattr
> +_syscall4(int, sys_sched_getattr, pid_t, pid, struct sched_attr *, attr, 
> unsigned int, size, unsigned int, flags);
> +#define __NR_sys_sched_setattr __NR_sched_setattr
> +_syscall3(int, sys_sched_setattr, pid_t, pid, struct sched_attr *, attr, 
> unsigned int, flags);
>   #define __NR_sys_getcpu __NR_getcpu
>   _syscall3(int, sys_getcpu, unsigned *, cpu, unsigned *, node, void *, tcache);
>   _syscall4(int, reboot, int, magic1, int, magic2, unsigned int, cmd,
> @@ -10593,6 +10597,57 @@ static abi_long do_syscall1(void *cpu_env, int num, 
> abi_long arg1,
>           }
>       case TARGET_NR_sched_getscheduler:
>           return get_errno(sched_getscheduler(arg1));
> +    case TARGET_NR_sched_getattr:
> +        {
> +            struct target_sched_attr *target_scha;
> +            struct target_sched_attr scha;
> +            if (arg2 == 0) {
> +                return -TARGET_EINVAL;
> +            }


> +            ret = get_errno(sys_sched_getattr(arg1, &scha, arg3, arg4));
> +            if (!is_error(ret)) {
> +                if (!lock_user_struct(VERIFY_WRITE, target_scha, arg2, 0))

As sizeof(target_scha) can be greater than arg3, you should user lock_user() 
with arg3 as length.

> +                    return -TARGET_EFAULT;

QEMU style uses braces {} even for one line statement.

You can run scripts/checkpath.pl to check the style


> +                target_scha->size = tswap32(scha.size);
> +                target_scha->sched_policy = tswap32(scha.sched_policy);
> +                target_scha->sched_flags = tswap64(scha.sched_policy);
> +                target_scha->sched_nice = tswap32(scha.sched_nice);
> +                target_scha->sched_priority = tswap32(scha.sched_priority);
> +                target_scha->sched_runtime = tswap64(scha.sched_runtime);
> +                target_scha->sched_deadline = tswap64(scha.sched_deadline);
> +                target_scha->sched_period = tswap64(scha.sched_period);
> +                if (scha.size >= 0x38) {

You should use offsetot(target_sched_attr, sched_util_min) rather than 0x38.


> +                    target_scha->sched_util_min = tswap32(scha.sched_util_min);
> +                    target_scha->sched_util_max = tswap32(scha.sched_util_max);
> +                }
> +                unlock_user_struct(target_scha, arg2, 1);
> +            }
> +            return ret;
> +        }
> +    case TARGET_NR_sched_setattr:
> +        {
> +            struct target_sched_attr *target_scha;
> +            struct target_sched_attr scha;
> +            if (arg2 == 0) {
> +                return -TARGET_EINVAL;
> +            }
> +            if (!lock_user_struct(VERIFY_READ, target_scha, arg2, 1))
> +                return -TARGET_EFAULT;

same comment

> +            scha.size = tswap32(target_scha->size);
> +            scha.sched_policy = tswap32(target_scha->sched_policy);
> +            scha.sched_flags = tswap64(target_scha->sched_flags);
> +            scha.sched_nice = tswap32(target_scha->sched_nice);
> +            scha.sched_priority = tswap32(target_scha->sched_priority);
> +            scha.sched_runtime = tswap64(target_scha->sched_runtime);
> +            scha.sched_deadline = tswap64(target_scha->sched_deadline);
> +            scha.sched_period = tswap64(target_scha->sched_period);
> +            if (scha.size >= 0x38) {

same comment

> +                scha.sched_util_min = tswap32(target_scha->sched_util_min);
> +                scha.sched_util_max = tswap32(target_scha->sched_util_max);
> +            }
> +            unlock_user_struct(target_scha, arg2, 0);
> +            return get_errno(sys_sched_setattr(arg1, &scha, arg3));
> +        }
>       case TARGET_NR_sched_yield:
>           return get_errno(sched_yield());
>       case TARGET_NR_sched_get_priority_max:
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 0b13975937..715ec75462 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -2914,4 +2914,19 @@ struct target_statx {
>      /* 0x100 */
>   };
>   
> +/* from kernel's include/linux/sched/types.h */
> +struct target_sched_attr {
> +    uint32_t size;
> +    uint32_t sched_policy;
> +    uint64_t sched_flags;
> +    int32_t sched_nice;
> +    uint32_t sched_priority;
> +    uint64_t sched_runtime;
> +    uint64_t sched_deadline;
> +    uint64_t sched_period;
> +    // 0x30

Remove this comment

> +    uint32_t sched_util_min;
> +    uint32_t sched_util_max;
> +};
> +

Please, use abi_uint, abit_int, abi_ullong rather than uint32_t, int32_t and 
uint64_t.
These types forces alignment according to the target type.
        
Thanks,
Laurent