linux-kernel - Re: [PATCH v4 04/11] kernel/fork: Initialize mm's PASID

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87v8xhqs45.ffs@tglx>
Date:   Mon, 14 Feb 2022 18:23:54 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Fenghua Yu <fenghua.yu@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Ashok Raj <ashok.raj@...el.com>,
        Ravi V Shankar <ravi.v.shankar@...el.com>
Cc:     iommu@...ts.linux-foundation.org, x86 <x86@...nel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Fenghua Yu <fenghua.yu@...el.com>
Subject: Re: [PATCH v4 04/11] kernel/fork: Initialize mm's PASID

On Mon, Feb 07 2022 at 15:02, Fenghua Yu wrote:

> A new mm doesn't have a PASID yet when it's created. Initialize
> the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1).
>
> INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be
> allocated to a user process. Initializing the process's PASID to 0 may
> cause confusion that why the process uses the reserved kernel legacy DMA
> PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly
> tells the process doesn't have a valid PASID yet.
>
> Even though the only user of mm_pasid_init() is in fork.c, define it
> in <linux/sched/mm.h> as the first of three mm/pasid life cycle
> functions (init/set/drop) to keep these all together.
>
> Suggested-by: Dave Hansen <dave.hansen@...ux.intel.com>
> Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
> Reviewed-by: Tony Luck <tony.luck@...el.com>

Reviewed-by: Thomas Gleixner <tglx@...utronix.de>