Re: [libvirt] [PATCH v5 1/3] add new virDomainCoreDumpWithFormat API

On Wed, Mar 12, 2014 at 09:29:55AM -0600, Eric Blake wrote: > > On 03/12/2014 09:04 AM, Martin Kletzander wrote: >> > > On Thu, Mar 06, 2014 at 09:35:47AM +0000,qiaonuohan(a)cn.fujitsu.com wrote: >>> > >> --memory-only option is introduced without compression supported. Therefore, >>> > >> this is a freature regression of virsh dump. Now qemu has support dumping memory >> > > >> > > s/freature/feature/ >> > > >> > > but I would not use the word "regression" since that never worked. >> > > Also it would help mentioning the commit ID or a version it >> > > got included in qemu. On that note, is there a possibility of >> > > of introspection of that feature, so we can gracefully error out in >> > > case older qemu is used? > > > > Yes - qemu 2.0 is adding 'query-dump-guest-memory-capability', which can > > be used for two purposes: 1. if this command exists, 'dump-guest-memory' > > supports the new optional 'format' argument; and 2. calling this command > > will return a list of WHICH formats are supported by the given qemu > > binary (since configure-time choices can disable some of the formats > > from actually working). So you need to have a patch that modifies > > src/qemu/qemu_capabilities.[ch] to do the probing and set capability > > bits, so that we can gracefully error out when talking to a too-old > > qemu, or requesting a format that was not compiled in to a new qemu. > > Great. Could we have the compression parameter just as an arbitrary string then (properly checked for, etc.) so there is no need to adapt our code to qemu format additions?