On Thu, 15 Aug 2019 at 09:53, Aleksandar Markovic <aleksandar.m.m...@gmail.com> wrote: > > > We can accept draft > > extensions in QEMU as long as they are disabled by default.
> Hi, Alistair, Palmer, > > Is this an official stance of QEMU community, or perhaps Alistair's > personal judgement, or maybe a rule within risv subcomunity? Alistair asked on a previous thread; my view was: https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg03364.html and nobody else spoke up disagreeing (summary: should at least be disabled-by-default and only enabled by setting an explicit property whose name should start with the 'x-' prefix). In general QEMU does sometimes introduce experimental extensions (we've had them in the block layer, for example) and so the 'x-' property to enable them is a reasonably established convention. I think it's a reasonable compromise to allow this sort of work to start and not have to live out-of-tree for a long time, without confusing users or getting into a situation where some QEMU versions behave differently or to obsolete drafts of a spec without it being clear from the command line that experimental extensions are being enabled. There is also an element of "submaintainer judgement" to be applied here -- upstream is probably not the place for a draft extension to be implemented if it is: * still fast moving or subject to major changes of design direction * major changes to the codebase (especially if it requires changes to core code) that might later need to be redone entirely differently * still experimental thanks -- PMM