Re: [PATCH] xen: allow 8bit input in Xen serial console

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 28/07/15 18:02, Manfred Haertel wrote:
> The Xen serial console cuts off the most significant bit from input
> characters, so you can't use e.g. German umlauts when logging in to
> the DOM0 Linux system from the serial console.
>
> The following patch fixes that problem.

Thanks for the submission.  However, please sign your patch off, per

http://wiki.xen.org/wiki/Submitting_Xen_Project_Patches#Signing_off_a_patch

>
> --- xen/drivers/char/serial.c.orig    2015-07-28 18:44:49.443889719 +0200
> +++ xen/drivers/char/serial.c    2015-07-28 18:47:10.593728590 +0200
> @@ -66,7 +66,7 @@
>      spin_unlock_irqrestore(&port->rx_lock, flags);
>
>      if ( fn != NULL )
> -        (*fn)(c & 0x7f, regs);
> +        (*fn)(c, regs);
>  }
>
>  void serial_tx_interrupt(struct serial_port *port, struct
> cpu_user_regs *regs)
> @@ -297,7 +297,11 @@
>      } while ( ((handle & SERHND_LO) &&  (c & 0x80)) ||
>                ((handle & SERHND_HI) && !(c & 0x80)) );
>
> -    return c & 0x7f;
> +    if (handle & SERHND_HI)

Please read CODING_STYLE in the root of the tree, but to summarise here,
spaces inside the first level of brackes, so "if ( handle & SERHND_HI
)", and no braces for single statements.

> +    {
> +        c &= 0x7f;
> +    }
> +    return c;

I think in both cases you need to mask out the top bit if either
SERHND_HI or SERHND_LO is set, and leave all 8 bits alone if neither are
set. 

Both of these are opt-in with command line options, so the default
configuration in most cases pass 8-bit characters unmodified.  You
probably also want to patch docs/misc/xen-command-line.markdown to
indicate that choosing the 'H' or 'L' option will prevent the use of
8-bit characters.

~Andrew