linux-kernel - Re: [PATCH v9 3/8] KVM: arm/arm64: Introduce helpers to manipulate page table entries

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Date:   Mon, 3 Dec 2018 19:20:08 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Punit Agrawal <punit.agrawal@....com>, kvmarm@...ts.cs.columbia.edu
Cc:     suzuki.poulose@....com, marc.zyngier@....com,
        Catalin Marinas <catalin.marinas@....com>, will.deacon@....com,
        linux-kernel@...r.kernel.org, Russell King <linux@...linux.org.uk>,
        punitagrawal@...il.com, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v9 3/8] KVM: arm/arm64: Introduce helpers to manipulate
 page table entries

On 10/31/2018 11:27 PM, Punit Agrawal wrote:
> Introduce helpers to abstract architectural handling of the conversion
> of pfn to page table entries and marking a PMD page table entry as a
> block entry.

Why is this necessary ? we would still need to access PMD, PUD as is
without any conversion. IOW KVM knows the breakdown of the page table
at various levels. Is this something required from generic KVM code ?

> 
> The helpers are introduced in preparation for supporting PUD hugepages
> at stage 2 - which are supported on arm64 but do not exist on arm.

Some of these patches (including the earlier two) are good on it's
own. Do we have still mention in commit message about the incoming PUD
enablement as the reason for these cleanup patches ?