linux-kernel - Re: [PATCH v4] memregion: Add cpu_cache_invalidate

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] [day] [month] [year] [list]

Message-ID: <20221027192341.flsnbnmptd4t32ki@offworld>
Date:   Thu, 27 Oct 2022 12:23:41 -0700
From:   Davidlohr Bueso <dave@...olabs.net>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     Dan Williams <dan.j.williams@...el.com>, linux-cxl@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>, nvdimm@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] memregion: Add cpu_cache_invalidate_memregion()
 interface

On Thu, 27 Oct 2022, Dave Hansen wrote:

>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>> index 67745ceab0db..b68661d0633b 100644
>> --- a/arch/x86/Kconfig
>> +++ b/arch/x86/Kconfig
>> @@ -69,6 +69,7 @@ config X86
>>	select ARCH_ENABLE_THP_MIGRATION if X86_64 && TRANSPARENT_HUGEPAGE
>>	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
>>	select ARCH_HAS_CACHE_LINE_SIZE
>> +	select ARCH_HAS_CPU_CACHE_INVALIDATE_MEMREGION  if X86_64
>
>What is 64-bit only about this?
>
>I don't expect to have a lot of NVDIMMs or CXL devices on 32-bit
>kernels, but it would be nice to remove this if it's not strictly
>needed.  Or, to add a changelog nugget that says:
>
>	Restrict this to X86_64 kernels.  It would probably work on 32-
>	bit, but there is no practical reason to use 32-bit kernels and
>	no one is testing them.

Yes, this was to further limit the potential users.