linux-kernel - Re: [RFC PATCH v1 17/57] kvm: Remove PAGE_SIZE compile-time constant assumption

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Message-ID: <Zw2PBJsC99L4y_7c@google.com>
Date: Mon, 14 Oct 2024 14:37:08 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Ryan Roberts <ryan.roberts@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>, 
	Anshuman Khandual <anshuman.khandual@....com>, Ard Biesheuvel <ardb@...nel.org>, 
	Catalin Marinas <catalin.marinas@....com>, David Hildenbrand <david@...hat.com>, 
	Greg Marsden <greg.marsden@...cle.com>, Ivan Ivanov <ivan.ivanov@...e.com>, 
	Kalesh Singh <kaleshsingh@...gle.com>, Marc Zyngier <maz@...nel.org>, 
	Mark Rutland <mark.rutland@....com>, Matthias Brugger <mbrugger@...e.com>, 
	Miroslav Benes <mbenes@...e.cz>, Will Deacon <will@...nel.org>, kvm@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org
Subject: Re: [RFC PATCH v1 17/57] kvm: Remove PAGE_SIZE compile-time constant assumption

Nit, "KVM:" for the scope.

On Mon, Oct 14, 2024, Ryan Roberts wrote:
> To prepare for supporting boot-time page size selection, refactor code
> to remove assumptions about PAGE_SIZE being compile-time constant. Code
> intended to be equivalent when compile-time page size is active.
> 
> Modify BUILD_BUG_ON() to compare with page size limit.
> 
> Signed-off-by: Ryan Roberts <ryan.roberts@....com>
> ---
> 
> ***NOTE***
> Any confused maintainers may want to read the cover note here for context:
> https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/

The patch should still stand on its own.  Most people can probably suss out what
PAGE_SIZE_MIN is, but at the same time, it's quite easy to provide a more verbose
changelog that's tailored to the actual patch.  E.g.

  To prepare for supporting boot-time page size selection, refactor KVM's
  check on the size of the kvm_run structure to assert that the size is less
  than the smallest possible page size, i.e. that kvm_run won't overflow its
  page regardless of what page size is chosen at boot time.

With something like the above,

Reviewed-by: Sean Christopherson <seanjc@...gle.com>