Re: [PATCH v3 07/39] xen/riscv: introduce CPU_NONE

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

On 10/5/26 4:53 PM, Baptiste Le Duc wrote:
> > Introduce CPU_NONE, a CPU number which doesn't identify any physical
> > CPU, to be used wherever a pCPU has to be recorded but there may be
> > none.
> >
> > Its first user is vsfile_cpu in struct vimsic_state, which records the
> > pCPU whose h/w guest interrupt file backs the vCPU's IMSIC VS-file.
> > NR_CPUS has been used there as the value meaning that there is no such
> > pCPU, i.e. that the s/w VS-file is in use. NR_CPUS is however an upper
> Nit: It's hard to understand when reading the message why s/w is mentioning.
> I'd reword it to:
>      ```
>      NR_CPUS has been used there to mean that no h/w guest interrupt file is
>      attached (i.e. the vCPU uses the s/w VS-file), so there is no pCPU to
>      record.
>      ```
> > bound rather than a "no CPU" marker, and it already carries other
> > meanings: hartid_to_cpuid() returns it for a hart Xen doesn't know, and
> > pcpu_info[] uses it for an entry whose processor_id isn't valid yet.
> > Use CPU_NONE for vsfile_cpu instead, so that the s/w VS-file case can't
> > be mistaken for any of those.
> Nit: Same as above, I'd prefer something like:
>      ```
>      Use CPU_NONE for vsfile_cpu instead, so that "no h/w guest interrupt
>      file attached" can't be mistaken for an unknown hart or a not-yet-valid
>      pcpu_info[] entry.
>      ```
I will apply your suggestions.

> Reviewed-by: Baptiste Le Duc <baptiste.le-duc@xxxxxxxxxx>
Thanks!

~ Oleksii