[libvirt] [PATCH] qemu: Allow the user to specify vendor and product for disk

[Dave Allan]

On Thu, Nov 08, 2012 at 09:28:06AM +0800, Osier Yang wrote:
> On 2012年11月08日 05:04, Dave Allan wrote:
> >On Wed, Nov 07, 2012 at 11:24:43PM +0800, Osier Yang wrote:
> >>On 2012年11月05日 21:34, Martin Kletzander wrote:
> >>>On 11/05/2012 08:04 AM, Osier Yang wrote:
> >>>>QEMU supports to set vendor and product strings for disk since
> >>>>1.2.0 (only scsi-disk, scsi-hd, scsi-cd support it), this patch
> >>>>exposes it with new XML elements<vendor>   and<product>   of disk
> >>>>device.
> >>>>---
> >>>>  docs/formatdomain.html.in                          |   10 +++++
> >>>>  docs/schemas/domaincommon.rng                      |   10 +++++
> >>>>  src/conf/domain_conf.c                             |   30 ++++++++++++++++
> >>>>  src/conf/domain_conf.h                             |    2 +
> >>>>  src/qemu/qemu_command.c                            |   29 ++++++++++++++++
> >>>>  .../qemuxml2argv-disk-scsi-disk-vpd.args           |   13 +++++++
> >>>>  .../qemuxml2argv-disk-scsi-disk-vpd.xml            |   36 ++++++++++++++++++++
> >>>>  tests/qemuxml2argvtest.c                           |    4 ++
> >>>>  8 files changed, 134 insertions(+), 0 deletions(-)
> >>>>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-scsi-disk-vpd.args
> >>>>  create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-scsi-disk-vpd.xml
> >>>>
> >>>>diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
> >>>>index c8da33d..cc9e871 100644
> >>>>--- a/docs/formatdomain.html.in
> >>>>+++ b/docs/formatdomain.html.in
> >>>>@@ -1657,6 +1657,16 @@
> >>>>          of 16 hexadecimal digits.
> >>>>          <span class='since'>Since 0.10.1</span>
> >>>>        </dd>
> >>>>+<dt><code>vendor</code></dt>
> >>>>+<dd>If present, this element specifies the vendor of a virtual hard
> >>>>+        disk or CD-ROM device. It's a not more than 8 bytes alphanumeric string.
> >>>
> >>>Last sentence doesn't make sense, I suggest changing it to either: "It
> >>>can't be longer than 8 alphanumeric characters." or simply "Maximum 8
> >>>alphanumeric characters."
> >>
> >>Okay, honestly, I wasn't comfortable with the sentence, but can't
> >>get a better one at that time, :-) I will change your advise a bit:
> >>
> >>It must not be longer than 8 alphanumeric characters.
> >
> >Not to be pedantic, but what happens if you hand it doublebyte
> >characters?
> 
> Ah, good question, though QEMU will truncate the string to 8 bytes
> anyway, should we do some translation in libvirt? the problem is
> how to map the doublebytes vendors/product to single bytes ones,
> is there some public specification available? /me starts to think
> if it's snake leg (or breaking fly on the wheel) to do the checking
> if it's too heavy.

Mostly I was curious about how the code handled doublebyte characters,
but now that I think about it, the SCSI spec mandates 8 bytes of
ASCII[1], but it sounds like qemu is already enforcing that, so I
think it's fine just to let it be freeform and note the spec's
requirement in the documentation.

(I had to google "putting legs on a snake", and yes, we should avoid
that.)

Dave

[1] http://en.wikipedia.org/wiki/SCSI_Inquiry_Command