Re: [PATCH 0/8] x86/msr: Drop 32-bit variants of *_on_cpu() MSR functions

[Ingo Molnar]

* Jürgen Groß <jgross@xxxxxxxx> wrote:

> On 05.06.26 11:05, Ingo Molnar wrote:
> > 
> > * Juergen Gross <jgross@xxxxxxxx> wrote:
> > 
> > > Drop the variants using 2 32-bit values instead of a single 64-bit one
> > > of the *_on_cpu() MSR access functions.
> > > 
> > > Juergen Gross (8):
> > >    x86/msr: Switch rdmsr_on_cpu() to return a 64-bit quantity
> > >    x86/msr: Switch all callers of rdmsrq_on_cpu() to use rdmsr_on_cpu()
> > >    x86/msr: Switch wrmsr_on_cpu() to use a 64-bit quantity
> > >    x86/msr: Switch all callers of wrmsrq_on_cpu() to use wrmsr_on_cpu()
> > >    x86/msr: Switch rdmsr_safe_on_cpu() to return a 64-bit quantity
> > >    x86/msr: Switch all callers of rdmsrq_safe_on_cpu() to use rdmsr_safe_on_cpu()
> > >    x86/msr: Switch wrmsr_safe_on_cpu() to use a 64-bit quantity
> > >    x86/msr: Switch all callers of wrmsrq_safe_on_cpu() to use  wrmsr_safe_on_cpu()
> > 
> > To sum up my review feedback for the invididual patches, we want
> > to do this instead:
> > 
> >    x86/msr: Convert rdmsrl_on_cpu() users to rdmsrq_on_cpu()
> >    x86/msr: Drop the rdmsrl_on_cpu() alias to rdmsrq_on_cpu()
> > 
> >    x86/msr: Switch all callers of rdmsr_on_cpu() to use rdmsrq_on_cpu()
> >    x86/msr: Remove the unused rdmsr_on_cpu() API
> > 
> >    x86/msr: Switch all callers of wrmsr_on_cpu() to use wrmsrq_on_cpu()
> >    x86/msr: Remove unused wrmsr_on_cpu() API
> > 
> >    x86/msr: Switch all callers of rdmsr_safe_on_cpu() to use rdmsrq_safe_on_cpu()
> >    x86/msr: Remove unused rdmsr_safe_on_cpu() API
> > 
> >    x86/msr: Switch all callers of wrmsr_safe_on_cpu() to use wrmsrq_safe_on_cpu()
> >    x86/mrs: Remove unused wrmsrq_safe_on_cpu() API
> > 
> > Note how there's no "conversion" of the 32-bit API itself in this
> > approach, we just do a straightforward migration of the users to
> > the already existing 64-bit APIs, then remove any unused APIs.
> 
> Fine with me, but I just wanted to get rid of the "q" and "l" suffices
> completely, as they serve no special purpose after dropping all other
> variants.
> 
> OTOH if wanted such a switch could be done later easily.

Well, we had a similar discussion back when we standardized on
rdmsrq() and wrmsrq(), and we use them as our primary 64-bit
MSR handling APIs. Why have a different pattern in any of the
derived APIs? It should really use the same conceptual namespace,
not some confusing mixture of two naming schemes.

Thanks,

	Ingo