Re: [virtio-dev] Re: [PATCH] virtio-gpio: Specify character encoding for gpio names

[Stefan Hajnoczi <stefanha@redhat.com>]

On Wed, Aug 18, 2021 at 02:02:19PM +0200, Arnd Bergmann wrote:
> On Wed, Aug 18, 2021 at 1:31 PM Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > diff --git a/virtio-gpio.tex b/virtio-gpio.tex
> > index 5da16d920aa3..0b0689cceb08 100644
> > --- a/virtio-gpio.tex
> > +++ b/virtio-gpio.tex
> > @@ -119,7 +119,8 @@ \subsubsection{requestq Operation: Get Line Names}\label{sec:Device Types / GPIO
> >  order of the GPIO line numbers. The names of the GPIO lines are optional and may
> >  be present only for a subset of GPIO lines. If missing, then a zero-byte must be
> >  present for the GPIO line. If present, the name string must be zero-terminated
> > -and the name must be unique within a GPIO Device.
> > +and the name must be unique within a GPIO Device. The names of the GPIO lines
> > +are encoded in UTF-8.
> 
> I would prefer mandating this to be 7-bit ASCII, since Linux uses the string as
> a file name in the (deprecated) sysfs interface, and the more unusual symbols
> may be hard to type on the command line.
> 
> There is also a question about UTF-8 normalization of those strings: should
> the guest assume that the names within a device just have different binary
> representations, or also that they represent unique strings when there are
> multiple equivalent or compatible sequences?

I'm fine with either one. If there are technical limitations that make
ASCII a safer choice then that's fine.

virtio-blk uses ASCII while virtio-serial and virtiofs use UTF-8 for
strings.

Stefan

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