On Thu, Aug 15, 2019 at 2:07 AM Peter Maydell <peter.mayd...@linaro.org> wrote: > > 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).
Agreed! > > 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 Yep, agreed. For RISC-V I think this would extend to only allowing extensions that have backing from the foundation and are under active discussion. Alistair > > thanks > -- PMM
