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

Nakajima, Jun
2007-09-29T00:19:19Z

Jeremy Fitzhardinge wrote:
> Nakajima, Jun wrote:
> > Jeremy Fitzhardinge wrote:
> >
> >
> > > + .pv_irq_ops = {
> > > + .init_IRQ = native_init_IRQ,
> > > + .save_fl = native_save_fl,
> > > + .restore_fl = native_restore_fl,
> > > + .irq_disable = native_irq_disable,
> > > + .irq_enable = native_irq_enable,
> > > + .safe_halt = native_safe_halt,
> > > + .halt = native_halt,
> > > + },
> > >
> >
> > I think the halt stuff should be moved to pv_cpu_ops?
> >
> You mean halt's alternate "shutdown vcpu" meaning if you call it with
> interrupts disabled? Yeah, I'd be happy to have an explicit op for
> that, rather than making it a secondary overloaded meaning. And use
> "safe_halt" for all uses of "wait for next interrupt".

Yes. For the native, "safe_halt" is "sti; hlt". The "native_halt" is
just "hlt". So the para_virt part of "hlt" could be moved to pv_cpu_ops,
and the "sti" part stays in pv_irq_ops.

>
> > > + .pv_misc_ops = {
> > > + .set_lazy_mode = paravirt_nop,
> > > + },
> > >
> >
> > Or you can split it to pv_cpu_ops and pv_mmu_ops, assuming that they
> > don't need to interact with each other in terms of the lazy
handling.
> >
>
> You mean have separate lazy_mmu and lazy_cpu (lazy_context_switch)
ops?
> Possible, but they're still exclusive. (I think VMI, at least,
assumes
> that you can't have lazy_mmu and lazy_cpu active at the same time, and
> its nice to enforce this in the interface.)

Okay I understand what you are saying.

>
> But having a whole misc structure for this interface is pretty warty,
I
> admit.
>
> J

Actually my concern was that such misc ops might grow to include the
things don't fit well anywhere else. To me, then pv_lazy_ops (with just
.set_mode) might be better.

Jun
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