Re: [PATCH v4 23/26] RFC: KVM: powerpc: Move processor compatibility check to hardware setup

[Isaku Yamahata]

On Fri, Sep 09, 2022 at 05:55:14AM +0000,
Christophe Leroy <christophe.leroy@xxxxxxxxxx> wrote:

> 
> 
> Le 09/09/2022 à 01:25, isaku.yamahata@xxxxxxxxx a écrit :
> > [Vous ne recevez pas souvent de courriers de isaku.yamahata@xxxxxxxxx. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]
> > 
> > From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > 
> > Move processor compatibility check from kvm_arch_processor_compat() into
> > kvm_arch_hardware_setup().  The check does model name comparison with a
> > global variable, cur_cpu_spec.  There is no point to check it at run time
> > on all processors.
> > 
> > Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx
> > Cc: Fabiano Rosas <farosas@xxxxxxxxxxxxx>
> > ---
> >   arch/powerpc/kvm/powerpc.c | 13 +++++++++++--
> >   1 file changed, 11 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> > index 7b56d6ccfdfb..7e3a6659f107 100644
> > --- a/arch/powerpc/kvm/powerpc.c
> > +++ b/arch/powerpc/kvm/powerpc.c
> > @@ -444,12 +444,21 @@ int kvm_arch_hardware_enable(void)
> > 
> >   int kvm_arch_hardware_setup(void *opaque)
> >   {
> > -       return 0;
> > +       /*
> > +        * kvmppc_core_check_processor_compat() checks the global variable.
> > +        * No point to check on all processors or at runtime.
> > +        * arch/powerpc/kvm/book3s.c: return 0
> > +        * arch/powerpc/kvm/e500.c: strcmp(cur_cpu_spec->cpu_name, "e500v2")
> > +        * arch/powerpc/kvm/e500mc.c: strcmp(cur_cpu_spec->cpu_name, "e500mc")
> > +        *                            strcmp(cur_cpu_spec->cpu_name, "e5500")
> > +        *                            strcmp(cur_cpu_spec->cpu_name, "e6500")
> > +        */
> 
> This explanation shouldn't be in the code. The content of other file may 
> change in the future, the files may be renamed or deleted, new files may 
> be added. And there is no added value with that comment.
> 
> That detailed explanation should go in the commit message.

Ok, will move the comment into the commit message.
-- 
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>