Re: [PATCH RFC] paravirt_ops: refactor struct paravirt_ops into smaller pv_*_ops

Zachary Amsden
2007-09-28T18:39:24Z

On Fri, 2007-09-28 at 11:10 -0700, Jeremy Fitzhardinge wrote:
> This patch refactors the paravirt_ops structure into groups of
> functionally related ops:
>
> pv_info - random info, rather than function entrypoints
> pv_init_ops - functions used at boot time (some for module_init too)
> pv_misc_ops - lazy mode, which didn't fit well anywhere else
> pv_time_ops - time-related functions
> pv_cpu_ops - various privileged instruction ops
> pv_irq_ops - operations for managing interrupt state
> pv_apic_ops - APIC operations
> pv_mmu_ops - operations for managing pagetables
>
> There are several motivations for this:
>
> 1. Some of these ops will be general to all x86, and some will be
> i386/x86-64 specific. This makes it easier to share common stuff
> while allowing separate implementations where needed.
>
> 2. At the moment we must export all of paravirt_ops, but modules only
> need selected parts of it. This allows us to export on a case by case
> basis (and also choose which export license we want to apply).

We shouldn't need to export pv_init_ops. It is debatable whether
CR2/CR3 should be part of CPU or MMU ops. Also, can we drop write_cr2?
It isn't used anywhere, so the only reason to keep it is symmetry.
Which was a fine argument when it was an inline, but now it just adds
unused junk to the code.

> This still needs to be reconciled with the x86 merge and glommer's
> paravirt_ops unification work.

Those issues aside, this looks great. I'll give it a whirl today.

Zach