* John Snow (js...@redhat.com) wrote: > > > On 1/27/20 3:43 PM, Peter Krempa wrote: > > On Mon, Jan 27, 2020 at 14:39:02 -0500, John Snow wrote: > >> > >> > >> On 1/27/20 5:36 AM, Maxim Levitsky wrote: > >>> This patch series is bunch of cleanups > >>> to the hmp monitor code. > >>> > >>> This series only touched blockdev related hmp handlers. > >>> > >>> No functional changes expected other that > >>> light error message changes by the last patch. > >>> > >>> This was inspired by this bugzilla: > >>> https://bugzilla.redhat.com/show_bug.cgi?id=1719169 > >>> > >>> Basically some users still parse hmp error messages, > >>> and they would like to have them prefixed with 'Error:' > >>> > >> > >> HMP isn't meant to be parsed. It's explicitly *not* API or ABI. I do > >> like consistency in my UIs (it's useful for human eyes, too), but I'd > >> like to know more about the request. > > > > That's true as long as there's an stable replacement ... see below. > > > > Thanks for the context! > > >> > >> Is this request coming from libvirt? Can we wean them off of this > >> interface? What do they need as a replacement? > > > > There are 5 commands that libvirt still has HMP interfaces for: > > > > drive_add > > drive_del > > > > savevm > > loadvm > > delvm > > > > From upstream point of view there's no value in adding the 'error' > > prefix to drive_add/drive_del as libvirt now uses blockdev-add/del QMP > > command instead which have implicit error propagation. > > > > As thought. > > > There are no replacements for the internal snapshot commands, but they > > reported the 'error' prefix for some time even before this series. > > > > Said that, please don't break savevm/loadvm/delvm until a QMP > > replacement is added. > > > > Yes, noted. I wonder where userfaultfd write support is these days...
How would that help you there? Dave > > The bug was reported at the time when libvirt didn't use blockdev yet, > > but at this point it's pointless from our side. This wouldn't even fix > > the scenario when old (pre-5.10) libvirt would use new qemu because the > > drive-add handler never checked the error prefix. > > > > [1] > > https://libvirt.org/git/?p=libvirt.git;a=blob;f=src/qemu/qemu_monitor_text.c;h=9135a11f0a3aae718c86bb199112fba8d16d4d80;hb=HEAD > > > > Thank you for the report from libvirtville :) > > --js -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
