linux-kernel - Re: [PATCH 0/3] KVM: x86/mmu: Use kernel's PG_LEVEL

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Date:   Tue, 28 Apr 2020 10:14:30 -0400
From:   Barret Rhoden <brho@...gle.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] KVM: x86/mmu: Use kernel's PG_LEVEL_* enums

On 4/27/20 8:54 PM, Sean Christopherson wrote:
> Drop KVM's PT_{PAGE_TABLE,DIRECTORY,PDPE}_LEVEL KVM enums in favor of the
> kernel's PG_LEVEL_{4K,2M,1G} enums, which have far more user friendly
> names.

thanks for doing this - it fell off my radar.

all 3:

Reviewed-by: Barret Rhoden <brho@...gle.com>

> 
> The KVM names were presumably intended to abstract away the page size.  In
> practice, the abstraction is only useful for a single line of code, a PSE
> paging related large page check.  For everything else, the abstract names
> do nothing but obfuscate the code.
> 
> Boot tested a PSE kernel under 32-bit KVM and 64-bit KVM, with and without
> EPT enabled.  Patches 2 and 3 generate no binary difference relative to
> patch 1 when compared via "objdump -d".
> 
> Sean Christopherson (3):
>    KVM: x86/mmu: Tweak PSE hugepage handling to avoid 2M vs 4M conundrum
>    KVM: x86/mmu: Move max hugepage level to a separate #define
>    KVM: x86/mmu: Drop KVM's hugepage enums in favor of the kernel's enums
> 
>   arch/x86/include/asm/kvm_host.h |  13 +---
>   arch/x86/kvm/mmu/mmu.c          | 118 +++++++++++++++-----------------
>   arch/x86/kvm/mmu/page_track.c   |   4 +-
>   arch/x86/kvm/mmu/paging_tmpl.h  |  18 ++---
>   arch/x86/kvm/mmu_audit.c        |   6 +-
>   arch/x86/kvm/svm/svm.c          |   2 +-
>   arch/x86/kvm/vmx/vmx.c          |   6 +-
>   arch/x86/kvm/x86.c              |   4 +-
>   8 files changed, 79 insertions(+), 92 deletions(-)
>