From: Andrew Morton <akpm@linux-foundation.org>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Ryusuke Konishi <konishi.ryusuke@gmail.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Jann Horn <jannh@google.com>,
kasan-dev@googlegroups.com
Subject: Re: [PATCH v2] x86/kfence: Fix booting on 32bit non-PAE systems
Date: Mon, 26 Jan 2026 13:24:50 -0800 [thread overview]
Message-ID: <20260126132450.fe903384a227a558fab50536@linux-foundation.org> (raw)
In-Reply-To: <20260126211046.2096622-1-andrew.cooper3@citrix.com>
On Mon, 26 Jan 2026 21:10:46 +0000 Andrew Cooper <andrew.cooper3@citrix.com> wrote:
> The original patch inverted the PTE unconditionally to avoid
> L1TF-vulnerable PTEs, but Linux doesn't make this adjustment in 2-level
> paging.
>
> Adjust the logic to use the flip_protnone_guard() helper, which is a nop on
> 2-level paging but inverts the address bits in all other paging modes.
>
> This doesn't matter for the Xen aspect of the original change. Linux no
> longer supports running 32bit PV under Xen, and Xen doesn't support running
> any 32bit PV guests without using PAE paging.
Great thanks. I'll add
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
and, importantly,
Cc: <stable@vger.kernel.org>
to help everything get threaded together correctly.
I'll queue this as a 6.19-rcX hotfix.
next prev parent reply other threads:[~2026-01-26 21:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-06 18:04 [PATCH] x86/kfence: Avoid writing L1TF-vulnerable PTEs Andrew Cooper
2026-01-07 11:31 ` Alexander Potapenko
2026-01-07 12:01 ` Andrew Cooper
2026-01-07 23:17 ` Andrew Morton
2026-01-26 19:07 ` [REGRESSION] x86_32 boot hang in 6.19-rc7 caused by b505f1944535 ("x86/kfence: avoid writing L1TF-vulnerable PTEs") Ryusuke Konishi
2026-01-26 19:39 ` Andrew Cooper
2026-01-26 19:52 ` Ryusuke Konishi
2026-01-26 19:54 ` Borislav Petkov
2026-01-26 20:22 ` Andrew Cooper
2026-01-26 20:41 ` Ryusuke Konishi
2026-01-26 20:43 ` Andrew Cooper
2026-01-26 20:25 ` Dave Hansen
2026-01-26 20:24 ` Andrew Morton
2026-01-26 20:36 ` Dave Hansen
2026-01-26 21:06 ` [PATCH] x86/kfence: Fix booting on 32bit non-PAE systems Andrew Cooper
2026-01-26 21:08 ` Andrew Cooper
2026-01-26 21:10 ` [PATCH v2] " Andrew Cooper
2026-01-26 21:24 ` Andrew Morton [this message]
2026-01-26 21:56 ` Borislav Petkov
2026-01-26 22:01 ` Andrew Cooper
2026-01-26 22:09 ` Borislav Petkov
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