[libvirt] [PATCH v3 2/4] qemu: add dtb capability

[Yin Olivia-R63875]

Hi Eric,

Thanks for the comments. Could you please help review the next version?

Best Regards,
Olivia

> -----Original Message-----
> From: Eric Blake [mailto:eblake at redhat.com]
> Sent: Thursday, February 28, 2013 1:02 AM
> Cc: Yin Olivia-R63875; libvir-list at redhat.com
> Subject: Re: [libvirt] [PATCH v3 2/4] qemu: add dtb capability
> 
> On 02/27/2013 09:56 AM, Eric Blake wrote:
> 
> >> @@ -944,6 +945,8 @@ virQEMUCapsComputeCmdFlags(const char *help,
> >>      }
> >>      if (strstr(help, "-uuid"))
> >>          virQEMUCapsSet(qemuCaps, QEMU_CAPS_UUID);
> >> +    if (strstr(help, "-dtb"))
> >> +        virQEMUCapsSet(qemuCaps, QEMU_CAPS_DTB);
> >
> > This won't work.  -dtb did not exist prior to qemu 1.2, and for all
> > qemu newer than 1.2, we do NOT scrape '-help' output; instead, we use
> > QMP query commands.  You need to figure out the corresponding QMP
> > command that we can use to tell when dtb support exists in qemu.
> 
> I stand (slightly) corrected: it looks like -dtb was added in qemu 1.1
> (qemu commit 379b5c7), which means we DO need -help scraping for that
> version of qemu.  Then, since it predates when QMP queries are reliable,
> you can get away with blindly setting QEMU_CAPS_DTB when targetting a qemu
> new enough to support QMP queries without actually having to query for it.
> But it's still something to be fixed before this patch is ready :)
> 
> --
> Eric Blake   eblake redhat com    +1-919-301-3266
> Libvirt virtualization library http://libvirt.org