Re: [PATCH] KVM: PPC: Book3S: Add support for H_IPOLL and H_XIRR_X in XICS emulation

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On 05/29/2013 06:57:32 PM, Benjamin Herrenschmidt wrote:
On Wed, 2013-05-29 at 18:38 -0500, Scott Wood wrote:

> > Yes. I'd like to have them in. Their implementation is actually fairly > > trivial and they cannot be emulated by qemu if the rest of the XICS is
> > in the kernel, so it's a problem.
>
> OK. Does it make more sense for you to take it as Paul suggested, or
> for Gleb or Marcelo to pick it up directly?

I'll take it.

Acked-by: Scott Wood <scottwood@xxxxxxxxxxxxx>

> Then rm_action should always be 0 for these hcalls, right? So there's
> no correctness reason to keep the hcalls in separate switch
> statements. You shave off a few cycles checking rm_action, at the cost
> of needing to change kvmppc_xics_hcall() if a real-mode version of
> these hcalls is ever done.

No, because rm_action will also be 0 if the hcall was fully done in real mode (which can happen, that's our fast path), in which case we do *NOT*
want to to be re-done in virtual mode.

That's why we always return whether rm_action is 0 or not when real-mode
is enabled.

Oh, I misread the code and thought the decision to return was based on the return value of kvmppc_xics_rm_complete. Sorry about that. :-(

-Scott
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