Re: [Qemu-devel] [PATCH v2 03/18] xen: introduce 'xen-block', 'xen-disk' and 'xen-cdrom'

[Paul Durrant <Paul.Durrant@citrix.com>]

> -----Original Message-----
> From: Anthony PERARD [mailto:anthony.perard@citrix.com]
> Sent: 07 December 2018 14:35
> To: Paul Durrant <Paul.Durrant@citrix.com>
> Cc: qemu-devel@nongnu.org; qemu-block@nongnu.org; xen-
> devel@lists.xenproject.org; Kevin Wolf <kwolf@redhat.com>; Max Reitz
> <mreitz@redhat.com>; Stefano Stabellini <sstabellini@kernel.org>
> Subject: Re: [PATCH v2 03/18] xen: introduce 'xen-block', 'xen-disk' and
> 'xen-cdrom'
> 
> On Thu, Dec 06, 2018 at 03:08:29PM +0000, Paul Durrant wrote:
> > +static char *disk_to_vbd_name(unsigned int disk)
> > +{
> > +    char *name, *prefix = (disk >= 26) ?
> > +        disk_to_vbd_name((disk / 26) - 1) : g_strdup("");
> > +
> > +    name = g_strdup_printf("%s%c", prefix, 'a' + disk);
> 
> I don't think that works, if disk is 27, we do ('a' + 27) here. It's
> probably missing a `disk % 26`.

Damn, yes I was not allowing the >2 letters.

> 
> > +    g_free(prefix);
> > +
> > +    return name;
> > +}
> 
> [...]
> 
> > +static unsigned int vbd_name_to_disk(const char *name, const char
> **endp)
> > +{
> > +    unsigned int disk = 0;
> > +
> > +    while (*name != '\0') {
> > +        if (!g_ascii_isalpha(*name) || !g_ascii_islower(*name)) {
> > +            break;
> > +        }
> > +
> > +        disk *= 26;
> > +        disk += *name++ - 'a';
> > +    }
> > +    *endp = name;
> > +
> > +    return disk;
> > +}
> > +
> > +static void xen_block_set_vdev(Object *obj, Visitor *v, const char
> *name,
> > +                               void *opaque, Error **errp)
> > +{
> 
> Setting vdev doesn't work. I've tried to add a disk `xvdaa', and it
> result in `xvda', or `d0p0' (in the trace). (Same result with `xvdaaa',
> and 'xvdba' gives 'xvdaa'/d26p0)
> 

Ok, that's weird. I'll have to figure that out.

  Paul

> --
> Anthony PERARD