Re: [Qemu-devel] [PATCH next v2 00/74] QOM CPUState, part 3: CPU reset

[Alexander Graf <agraf@suse.de>]

On 05/10/2012 02:10 AM, Andreas Färber wrote:
> Hello,
>
> Based on my CPUState patches for 1.1 (qom-cpu-1.1) this series kills off the
> cpu_state_reset() function, which had been renamed as an interim solution
> to free the identifier "cpu_reset" for QOM.
>
> The interested observer may note that the earlier sh4 SH7750 patches (that
> have been deferred due to time constraints for 1.1) were a test run and
> serve as template for propagating xxxCPU throughout the code base:
>
> (i) In target-specific code, accessing CPUxxxState* is a cheap pointer
> dereference from xxxCPU (&cpu->env), so xxxCPU should be preferred for any
> static helper functions and QOM/qdev state structs because fields in CPUState
> and in xxxCPU will increase over time. In state structs this also paves
> the way for QOM child<>  or link<>  properties.
>
> (ii) In TCG helpers, the target's xxxCPU can be obtained via xxx_env_get_cpu().
> Be aware that this incurs one QOM cast.
>
> (iii) In generic code, the base CPU can be obtained via ENV_GET_CPU() macro.
> Note that this incurs two QOM casts, so local variables should be preferred
> over repeated macro usage within a function.
>
> (iv) In generic functions, only after all usages of env have been eliminated
> can the argument be changed from CPUArchState to CPUState.
>
> (v) Opaque xxxCPU* values are assigned directly to xxxCPU*, to save QOM casts;
> to CPUState* via CPU() cast, in case the casting mechanism ever gets changed.
>
> Historically, this series has been cherry-picked from a larger CPUState
> refactoring (guess why) and reordered to group subsystems and to enforce
> get, pass, use order.
> I had checked v1 to compile on ...
> * openSUSE 12.1 x86_64 w/KVM,
> * openSUSE Factory ppc w/KVM (with the AREG0 #error suppressed),
> * mingw32/64 cross-builds,
> * OpenBSD 5.1 amd64.
> Thus I'm confident that I got order, return types and local variables right;
> changes to opaque values however (keyword "pass") should be reviewed carefully.
> v2 fixes the changed cpu_init macros to return NULL if CPU init failed.
>
> Again, target maintainers are requested to start queuing their patches on their
> -next branches, where available, to avoid collisions.
> I've been careful to verbosely document which change is for what; the targets
> are not interdependent except for the final patch, neither is linux-user.
> PReP patches depend on target-ppc, so should go through the ppc tree please.
> Only target-mips actually depends on a 1.1 patch (the comment drop).
>
> Some logical next steps that were not strictly necessary for cpu_reset() have
> been deferred to part 4, including s390x and some more pxa2xx refactorings.
>
> Available for testing and cherry-picking (not pulling!) from:
> git://github.com/afaerber/qemu-cpu.git qom-cpu-reset.v2
> https://github.com/afaerber/qemu-cpu/commits/qom-cpu-reset.v2
>
> Regards,
> Andreas
>
> Cc: Anthony Liguori<anthony@codemonkey.ws>
> Cc: Paolo Bonzini<pbonzini@redhat.com>
> Cc: Igor Mammedov<imammedo@redhat.com>
>
> Cc: Peter Maydell<peter.maydell@linaro.org>
> Cc: Alexander Graf<agraf@suse.de>
> Cc: qemu-ppc<qemu-ppc@nongnu.org>
> Cc: Blue Swirl<blauwirbel@gmail.com>
> Cc: Edgar E. Iglesias<edgar.iglesias@gmail.com>
> Cc: Max Filippov<jcmvbkbc@gmail.com>
> Cc: Michael Walle<michael@walle.cc>
> Cc: Aurelien Jarno<aurelien@aurel32.net>
> Cc: Richard Henderson<rth@twiddle.net>
> Cc: Riku Voipio<riku.voipio@iki.fi>

Very simple, nice and clean ;)

PowerPC parts are:

   Acked-by: Alexander Graf <agraf@suse.de>


Alex