Re: [PATCH 2/6] svm: Improve type of cpu_has_svm_feature

[George Dunlap <george.dunlap@xxxxxxxxx>]

On Mon, Feb 19, 2024 at 10:03 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>
> On 06.02.2024 02:20, George Dunlap wrote:
> > The "effective type" of the cpu_has_svm_feature macro is effectively
> > an unsigned log with one bit set (or not); at least one place someone
> > felt compelled to do a !! to make sure that they got a boolean out of
> > it.
> >
> > Ideally the whole of this would be folded into the cpufeature.h
> > infrastructure.  But for now, duplicate the more type-safe static
> > inlines in that file, and remove the !!.
> >
> > Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxx>
>
> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
> albeit preferably with ...
>
> > --- a/xen/arch/x86/include/asm/hvm/svm/svm.h
> > +++ b/xen/arch/x86/include/asm/hvm/svm/svm.h
> > @@ -38,7 +38,10 @@ extern u32 svm_feature_flags;
> >  #define SVM_FEATURE_SSS           19 /* NPT Supervisor Shadow Stacks */
> >  #define SVM_FEATURE_SPEC_CTRL     20 /* MSR_SPEC_CTRL virtualisation */
> >
> > -#define cpu_has_svm_feature(f) (svm_feature_flags & (1u << (f)))
> > +static inline bool cpu_has_svm_feature(unsigned int feat)
> > +{
> > +    return svm_feature_flags & (1u << (feat));
>
> ... the inner pair of parentheses dropped.

Done, thanks.

 -George