Re: [libvirt] patch: allow disk cache mode to be specified in a domain's xml definition.

Daniel P. Berrange wrote: Ok. Let's address the above when we're satisfied with the state of the patch as we have at least one open issue (as below). Yes you mentioned this in your earlier (off list) reply to me. I did produce a patch version using the VIR_ENUM_DECL/VIR_ENUM_IMPL macros but thought they may not be the most natural fit for the task since there is no way to multiply define a particular enum value (eg: cache "none" || "off"). Also a given hypervisor will likely support only a subset of the internally enumerated option space forcing dummy-out of unused cache modes. But that is speculative and I don't have a strong bias either way. So I've reverted to use of VIR_ENUM_DECL/VIR_ENUM_IMPL here. I was trying to address part of this as above. But in general I don't see how we can force an error in advance of launching qemu without some information beforehand of whether we're dealing with an old vs. new syntax qemu. One way to do so is to test launch "qemu --help" and let it tell us what it accepts. Alternatively we can just let qemu error exit in the case an old/new qemu version doesn't recognize the alternate syntax. Other than the above I believe I've incorporated all of your remaining suggestions. Attached is an updated patch. -john -- john.cooper(a)redhat.com