Re: [RFC PATCH 11/16] target/arm/kvm-rme: Add Realm Personalization Value parameter

[Richard Henderson]

On 1/27/23 05:07, Jean-Philippe Brucker wrote:
> +static int rme_parse_rpv(uint8_t *out, const char *in, Error **errp)
> +{
> +    int ret;
> +    size_t in_len = strlen(in);
> +
> +    /* Two chars per byte */
> +    if (in_len > KVM_CAP_ARM_RME_RPV_SIZE * 2) {
> +        error_setg(errp, "Realm Personalization Value is too large");
> +        return -E2BIG;
> +    }
> +
> +    /*
> +     * Parse as big-endian hexadecimal number (most significant byte on the
> +     * left), store little-endian, zero-padded on the right.
> +     */
> +    while (in_len) {
> +        /*
> +         * Do the lower nibble first to catch invalid inputs such as '2z', and
> +         * to handle the last char.
> +         */
> +        in_len--;
> +        ret = sscanf(in + in_len, "%1hhx", out);
> +        if (ret != 1) {
> +            error_setg(errp, "Invalid Realm Personalization Value");
> +            return -EINVAL;
> +        }
> +        if (!in_len) {
> +            break;
> +        }
> +        in_len--;
> +        ret = sscanf(in + in_len, "%2hhx", out++);
> +        if (ret != 1) {
> +            error_setg(errp, "Invalid Realm Personalization Value");
> +            return -EINVAL;
> +        }
> +    }

I think this parsing is late, and should be done

> +static void rme_set_rpv(Object *obj, const char *value, Error **errp)
> +{
> +    RmeGuest *guest = RME_GUEST(obj);
> +
> +    g_free(guest->personalization_value);
> +    guest->personalization_value = g_strdup(value);
> +}

here, when the value is set, so that the error is produced at the proper time.


r~