[PATCH v2 04/13] KVM: arm64: Refactor sys_regs.h, c for nVHE reuse

[Fuad Tabba]

Hi Will,

On Thu, Jul 1, 2021 at 2:09 PM Will Deacon <will at kernel.org> wrote:
>
> On Tue, Jun 15, 2021 at 02:39:41PM +0100, Fuad Tabba wrote:
> > Refactor sys_regs.h and sys_regs.c to make it easier to reuse
> > common code. It will be used in nVHE in a later patch.
> >
> > No functional change intended.
> >
> > Signed-off-by: Fuad Tabba <tabba at google.com>
> > ---
> >  arch/arm64/kvm/sys_regs.c | 30 +-----------------------------
> >  arch/arm64/kvm/sys_regs.h | 35 +++++++++++++++++++++++++++++++++++
> >  2 files changed, 36 insertions(+), 29 deletions(-)
>
> [...]
>
> > diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h
> > index 9d0621417c2a..b8e2a4dd830f 100644
> > --- a/arch/arm64/kvm/sys_regs.h
> > +++ b/arch/arm64/kvm/sys_regs.h
> > @@ -11,6 +11,12 @@
> >  #ifndef __ARM64_KVM_SYS_REGS_LOCAL_H__
> >  #define __ARM64_KVM_SYS_REGS_LOCAL_H__
> >
> > +#include <linux/bsearch.h>
> > +
> > +#define reg_to_encoding(x)                                           \
> > +     sys_reg((u32)(x)->Op0, (u32)(x)->Op1,                           \
> > +             (u32)(x)->CRn, (u32)(x)->CRm, (u32)(x)->Op2)
> > +
> >  struct sys_reg_params {
> >       u8      Op0;
> >       u8      Op1;
> > @@ -21,6 +27,14 @@ struct sys_reg_params {
> >       bool    is_write;
> >  };
> >
> > +#define esr_sys64_to_params(esr)                                               \
> > +     ((struct sys_reg_params){ .Op0 = ((esr) >> 20) & 3,                    \
> > +                               .Op1 = ((esr) >> 14) & 0x7,                  \
> > +                               .CRn = ((esr) >> 10) & 0xf,                  \
> > +                               .CRm = ((esr) >> 1) & 0xf,                   \
> > +                               .Op2 = ((esr) >> 17) & 0x7,                  \
> > +                               .is_write = !((esr)&1) })
>
> Formatting has gone funny here (need spaces around the '&' in that last
> entry).

Will fix this.

> > +
> >  struct sys_reg_desc {
> >       /* Sysreg string for debug */
> >       const char *name;
> > @@ -152,6 +166,24 @@ static inline int cmp_sys_reg(const struct sys_reg_desc *i1,
> >       return i1->Op2 - i2->Op2;
> >  }
> >
> > +static inline int match_sys_reg(const void *key, const void *elt)
> > +{
> > +     const unsigned long pval = (unsigned long)key;
> > +     const struct sys_reg_desc *r = elt;
> > +
> > +     return pval - reg_to_encoding(r);
> > +}
> > +
> > +static inline const struct sys_reg_desc *
> > +find_reg(const struct sys_reg_params *params, const struct sys_reg_desc table[],
> > +      unsigned int num)
> > +{
> > +     unsigned long pval = reg_to_encoding(params);
> > +
> > +     return __inline_bsearch((void *)pval, table, num, sizeof(table[0]),
> > +                             match_sys_reg);
>
> You don't mention why you change bsearch() to __inline_bsearch().

It's because of linking with nvhe. Rather than copy the bsearch code
for nvhe, I thought I'd use the inline version of bsearch. I'll update
the comment to explain that.

Thanks,
/fuad

> Will