linux-kernel - Re: [PATCH v2 17/39] mm: Fixup places that call pte

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Message-ID: <20221003235619.qdoedbrcrplaa4tf@box.shutemov.name>
Date:   Tue, 4 Oct 2022 02:56:19 +0300
From:   "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>
To:     Rick Edgecombe <rick.p.edgecombe@...el.com>
Cc:     x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-mm@...ck.org,
        linux-arch@...r.kernel.org, linux-api@...r.kernel.org,
        Arnd Bergmann <arnd@...db.de>,
        Andy Lutomirski <luto@...nel.org>,
        Balbir Singh <bsingharora@...il.com>,
        Borislav Petkov <bp@...en8.de>,
        Cyrill Gorcunov <gorcunov@...il.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Eugene Syromiatnikov <esyr@...hat.com>,
        Florian Weimer <fweimer@...hat.com>,
        "H . J . Lu" <hjl.tools@...il.com>, Jann Horn <jannh@...gle.com>,
        Jonathan Corbet <corbet@....net>,
        Kees Cook <keescook@...omium.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Nadav Amit <nadav.amit@...il.com>,
        Oleg Nesterov <oleg@...hat.com>, Pavel Machek <pavel@....cz>,
        Peter Zijlstra <peterz@...radead.org>,
        Randy Dunlap <rdunlap@...radead.org>,
        "Ravi V . Shankar" <ravi.v.shankar@...el.com>,
        Weijiang Yang <weijiang.yang@...el.com>,
        joao.moreira@...el.com, John Allen <john.allen@....com>,
        kcc@...gle.com, eranian@...gle.com, rppt@...nel.org,
        jamorris@...ux.microsoft.com, dethoma@...rosoft.com,
        Yu-cheng Yu <yu-cheng.yu@...el.com>
Subject: Re: [PATCH v2 17/39] mm: Fixup places that call pte_mkwrite()
 directly

On Thu, Sep 29, 2022 at 03:29:14PM -0700, Rick Edgecombe wrote:
> From: Yu-cheng Yu <yu-cheng.yu@...el.com>
> 
> With the introduction of shadow stack memory there are two ways a pte can
> be writable: regular writable memory and shadow stack memory.
> 
> In past patches, maybe_mkwrite() has been updated to apply pte_mkwrite()
> or pte_mkwrite_shstk() depending on the VMA flag. This covers most cases
> where a PTE is made writable. However, there are places where pte_mkwrite()
> is called directly and the logic should now also create a shadow stack PTE
> in the case of a shadow stack VMA.
> 
>  - do_anonymous_page() and migrate_vma_insert_page() check VM_WRITE
>    directly and call pte_mkwrite(), which is the same as maybe_mkwrite()
>    in logic and intention. Just change them to maybe_mkwrite().

Looks like you folded change for do_anonymous_page() into the wrong patch.
I see the relevant change in the previous patch.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov