Re: [Qemu-devel] [RFC v4 05/71] cpu: move run_on_cpu to cpus-common

["Alex Bennée" <alex.bennee@linaro.org>]

Paolo Bonzini <pbonzini@redhat.com> writes:

> On 29/10/2018 22:39, Emilio G. Cota wrote:
>> I'm not convinced about adding an "assert(!user-mode)" to run_on_cpu.
>> Given that now it does not depend on the BQL, it could actually
>> work in user-mode if called. If we really wanted to make sure
>> that no user-mode would call it, then a compile-time check
>> would be better than an assert. But again, I fail to see what
>> we'd gain from that.
>>
>> For context, do_run_on_cpu et al. were moved to cpus-common.c by
>> d148d90ee8 ("cpus-common: move CPU work item management to
>> common code", 2016-09-27). The point was to consolidate the
>> run-on-cpu code in a common (softmmu & user-mode) file, since
>> user-mode needed async_run_on_cpu for exclusive work.
>>
>> Now we can finally make run_on_cpu generic as well.
>
> I agree, the run_on_cpu stuff should not be system-specific at all.

I'm happy to for it to be generic - just not broken ;-)

I'm not sure what sort of use cases it has at the moment given we use
start/end_exclusive for both atomics and system call marshalling in
linux-user. However have a common toolbox across system and linux-user
is a good thing.

>
> Paolo


--
Alex Bennée