Re: [PATCH v5 17/18] kvm: arm64: Limit the minimum number of page table levels

[Suzuki K Poulose]

On 09/25/2018 11:00 AM, Auger Eric wrote:
> Hi Suzuki,
>
> On 9/17/18 12:41 PM, Suzuki K Poulose wrote:
> > Since we are about to remove the lower limit on the IPA size,
> > make sure that we do not go to 1 level page table (e.g, with
> > 32bit IPA on 64K host with concatenation) to avoid splitting
> > the host PMD huge pages at stage2.
> >
> > Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
> > Cc: Christoffer Dall <cdall@xxxxxxxxxx>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> > ---
> >   arch/arm64/include/asm/stage2_pgtable.h |  8 +++++++-
> >   arch/arm64/kvm/reset.c                  | 12 +++++++++++-
> >   2 files changed, 18 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/stage2_pgtable.h b/arch/arm64/include/asm/stage2_pgtable.h
> > index 352ec4158fdf..6a56fdff0823 100644
> > --- a/arch/arm64/include/asm/stage2_pgtable.h
> > +++ b/arch/arm64/include/asm/stage2_pgtable.h
> > @@ -72,8 +72,14 @@
> >   /*
> >    * The number of PTRS across all concatenated stage2 tables given by the
> >    * number of bits resolved at the initial level.
> > + * If we force more number of levels than necessary, we may have
> more levels?


> > diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
> > index 76972b19bdd7..0393bb974b23 100644
> > --- a/arch/arm64/kvm/reset.c
> > +++ b/arch/arm64/kvm/reset.c

> > @@ -210,7 +219,8 @@ int kvm_arm_config_vm(struct kvm *kvm, unsigned long type)
> >   	vtcr |= (kvm_get_vmid_bits() == 16) ?
> >   		VTCR_EL2_VS_16BIT :
> >   		VTCR_EL2_VS_8BIT;
> > -	vtcr |= VTCR_EL2_LVLS_TO_SL0(stage2_pgtable_levels(KVM_PHYS_SHIFT));
> > +
> nit: new line not requested

Fixed all the above

Suzuki