Re: [PATCH] arm64/mm: Set only the PTE_DIRTY bit while preserving the HW dirty state

[Catalin Marinas]

On Thu, Jul 13, 2023 at 12:45:18PM +0530, Anshuman Khandual wrote:
> pte_mkdirty() creates dirty states both in SW and HW bits, which is really
> not required, either in pte_wrprotect() or pte_modify() for preserving the
> HW dirty state. Because pte_mkdirty() sets PTE_DIRTY and clears PTE_RDONLY
> as pte_write() always evaluates to be true - otherwise pte_hw_dirty() will
> not test out in the first place. Clearing PTE_RDONLY again is not required
> here because the pte is already in pte_hw_dirty() but might soon loose its
> dirty state thus requiring preservation in SW dirty bit i.e PTE_DIRTY.
> 
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>

Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>