Re: [Xen-devel] [PATCH V3] x86/altp2m: Hypercall to set altp2m view visibility

[Jan Beulich <jbeulich@xxxxxxxx>]

On 19.02.2020 10:18, Alexandru Stefan ISAILA wrote:
> @@ -4835,6 +4836,23 @@ static int do_altp2m_op(
>          break;
>      }
>  
> +    case HVMOP_altp2m_set_visibility:
> +    {
> +        uint16_t altp2m_idx = a.u.set_visibility.altp2m_idx;
> +
> +        if ( a.u.set_visibility.pad )
> +            rc = -EINVAL;
> +        else if ( !altp2m_active(d) )
> +            rc = -EOPNOTSUPP;
> +        else if ( a.u.set_visibility.visible )
> +            d->arch.altp2m_working_eptp[altp2m_idx] =
> +                d->arch.altp2m_eptp[altp2m_idx];
> +        else
> +            d->arch.altp2m_working_eptp[altp2m_idx] =
> +                mfn_x(INVALID_MFN);

Don't you need to bounds check the index before its use? And
shouldn't you return an error also for in-range ones which
aren't actually valid?

Jan

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