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References: <20220610143527.22974-1-kirill.shutemov@linux.intel.com> <20220610143527.22974-5-kirill.shutemov@linux.intel.com>
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From:   Alexander Potapenko <glider@google.com>
Date:   Fri, 17 Jun 2022 17:35:05 +0200
Message-ID: <CAG_fn=U4hETfYrRbZMJ2xEEgP+FzWmYX+u+Kr=x0NkytU6nGfg@mail.gmail.com>
Subject: Re: [PATCHv3 4/8] x86/mm: Handle LAM on context switch
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        Kostya Serebryany <kcc@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "H . J . Lu" <hjl.tools@gmail.com>,
        Andi Kleen <ak@linux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Fri, Jun 10, 2022 at 4:35 PM Kirill A. Shutemov
<kirill.shutemov@linux.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 th=
e
> 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@linux.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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