Re: [PATCH] kvm: arm/arm64: Rework gpa callback handlers

[Suzuki K Poulose]

On 24/03/17 18:00, Christoffer Dall wrote:
> On Mon, Mar 20, 2017 at 06:26:42PM +0000, Suzuki K Poulose wrote:
> > In order to perform an operation on a gpa range, the hyp iterates
>
> the hyp ?

To be precise "the host" ?

> > over each page in a user memory slot for the given range. This is
> > inefficient while dealing with a big range (e.g, a VMA), especially
> > while unmaping a range. At present, with stage2 unmap on a range with
> > a hugepage backed region, we clear the PMD when we unmap the first
> > page in the loop. The remaining iterations simply traverse the page table
> > down to the PMD level only to see that nothing is in there.
> >
> > This patch reworks the code to invoke the callback handlers on the
> > biggest range possible within the memory slot to avoid reduce the
> > number of iterations.
>
> avoid reduce?
>
> did you mean "to reduce the number of times the handler is called" ?

Yep, thanks for spotting.

> > Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> > Cc: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
> >  arch/arm/kvm/mmu.c | 31 +++++++++++++------------------
> >  1 file changed, 13 insertions(+), 18 deletions(-)
> >
> > diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
> > index 37e67f5..8357fed 100644
> > --- a/arch/arm/kvm/mmu.c
> > +++ b/arch/arm/kvm/mmu.c
...

> >
>
> Otherwise looks good:
>
> I can fix up the commit message when applying this.
>
> Reviewed-by: Christoffer Dall <cdall@xxxxxxxxxx>

Thanks

Suzuki