linux-kernel - Re: [PATCH 13/17] kvm-arm: Add stage2 page table modifiers

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Date:	Fri, 8 Apr 2016 19:03:02 +0200
From:	Christoffer Dall <christoffer.dall@...aro.org>
To:	Suzuki K Poulose <Suzuki.Poulose@....com>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
	marc.zyngier@....com, mark.rutland@....com, will.deacon@....com,
	catalin.marinas@....com
Subject: Re: [PATCH 13/17] kvm-arm: Add stage2 page table modifiers

On Fri, Apr 08, 2016 at 04:37:02PM +0100, Suzuki K Poulose wrote:
> On 08/04/16 14:42, Christoffer Dall wrote:
> >On Mon, Apr 04, 2016 at 05:26:13PM +0100, Suzuki K Poulose wrote:
> 
> >>
> >>-static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
> >>+static void clear_stage2_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
> >>  {
> >>-	pmd_t *pmd_table = pmd_offset(pud, 0);
> >>-	VM_BUG_ON(pud_huge(*pud));
> >>-	pud_clear(pud);
> >>+	pmd_t *pmd_table __maybe_unused = stage2_pmd_offset(pud, 0);
> >
> >The __maybe_unused are slightly ugly, so it may be nicer to create the
> >stage2_pmd_free() as static inline's if they're defined to do nothing
> >instead.
> >
> 
> Sure, we could do that for stage2. However, we will need to fix the host helpers
> as well for making such a change in the _hyp version (for 16K + 36bit VA).
> 

I thought the host helpers were already done like that, since we don't
need the __maybe_unused currently.  If it involves changing core code
etc. then don't bother.

Thanks,
-Christoffer