Re: [libvirt] [PATCH 3/8] conf, qemu: Add support for shmem model

On Fri, Oct 07, 2016 at 03:55:44PM +0100, Daniel P. Berrange wrote: This is the 'ivshmem' being implemented as default if you don't pick any due to the fact that there are some older domains that already have <shmem/> without <model/> and we're sure they are using 'ivshmem'. So we don't want to change that. We could add a MODEL_DEFAULT and MODEL_IVSHMEM, but we would have to set it to _IVSHMEM in the PostParse anyway because _DEFAULT doesn't make sense here (in contrast to other places/options). That is because libvirt *has* to choose the model, there is no way to let the hypervisor (QEMU) choose. It won't, it would just *not* be parsed. We're not iterating over all children elements, we're just picking the ones we want. Have you ever edited the XML and lost the stuff you added because of a typo? Well that's exactly why. And also why we added RNG schema validation, I believe. It's not that black-n-white, there are some grey areas. But we disabled the migration in previous commit due to the fact that it was never safe or that it would work for sure. Plus it doesn't make much sense, so IMNSHO we don't have to have a problem wrt migration.