On Thu, 7 Dec 2017 17:26:53 +0000 Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 7 December 2017 at 17:13, Peter Maydell <peter.mayd...@linaro.org> wrote: > > On 7 December 2017 at 17:07, Eduardo Habkost <ehabk...@redhat.com> wrote: > >> On Thu, Dec 07, 2017 at 04:53:59PM +0000, Peter Maydell wrote: > >>> On 7 December 2017 at 16:48, Igor Mammedov <imamm...@redhat.com> wrote: > >>> > On Thu, 7 Dec 2017 16:05:50 +0000 > >>> > Peter Maydell <peter.mayd...@linaro.org> wrote: > >>> > > >>> >> Hi; I'm currently writing '-cpu max' support for ARM. For that I'd > >>> >> like to be able to do the "probe host kernel for its supported feature > >>> >> set" in the CPU object's instance-init function, but I'd like to do > >> > >> I don't think instance_init is appropriate for that, as > >> object_free(object_new(t)) must be always safe to call and free > >> of side-effects for all types. Wouldn't it work if you do that > >> on realize? > > > > I think we need the information before realize, but I'll double > > check. > > We do need the information before realize, because the probe > is what tells us what feature bits we need to set, and the > ARM instance_post_init hook needs to look at those to determine > eg which other feature bits to set and which QOM properties to > expose as a result, and all that has to happen at init time, > not realize time. maybe it could be modeled after kvm_ppc_register_host_cpu_type(), i.e. create type with necessary feature bits set at cpu's class init time (sort of combo of what ppc and x86 do). i.e. one caches host's feature bits at cpu_class_init time and then loads applies them to object instance at instance init time, like in x86_cpu_initfn()->x86_cpu_load_def(). TBH: I do not recall why we have x86 max/host cpu types do feature loading at realize time instead of at class init like the rest of static cpu types. > thanks > -- PMM
