linux-kernel - Re: [PATCHv3 4/8] x86/mm: Handle LAM on context switch

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Date:   Fri, 17 Jun 2022 17:35:05 +0200
From:   Alexander Potapenko <glider@...gle.com>
To:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        "the arch/x86 maintainers" <x86@...nel.org>,
        Kostya Serebryany <kcc@...gle.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        "H . J . Lu" <hjl.tools@...il.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@...el.com>,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv3 4/8] x86/mm: Handle LAM on context switch

On Fri, Jun 10, 2022 at 4:35 PM Kirill A. Shutemov
<kirill.shutemov@...ux.intel.com> wrote:
>
> Linear Address Masking mode for userspace pointers encoded in CR3 bits.
> The mode is selected per-thread. Add new thread features indicate that the
> thread has Linear Address Masking enabled.
>
> switch_mm_irqs_off() now respects these flags and constructs CR3
> accordingly.
>
> The active LAM mode gets recorded in the tlb_state.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>


> +#ifdef CONFIG_X86_64
> +static inline u64 mm_cr3_lam_mask(struct mm_struct *mm)
> +{
> +       return mm->context.lam_cr3_mask;
> +}

Nit: can we have either "cr3_lam_mask" or "lam_cr3_mask" in both places?



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Alexander Potapenko
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