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

-----Original Message----- From: Eric Blake [mailto:eblake@redhat.com] Sent: Thursday, February 28, 2013 1:02 AM Cc: Yin Olivia-R63875; libvir-list(a)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