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From: Joerg Roedel <joro@8bytes.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
	bp@alien8.de, luto@kernel.org, kirill.shutemov@linux.intel.com,
	rick.p.edgecombe@intel.com, jgross@suse.com
Subject: Re: [RFC][PATCH 0/8] x86/mm: Simplify PAE page table handling
Date: Fri, 24 Jan 2025 08:58:32 +0100	[thread overview]
Message-ID: <Z5NIKGcgS2pMhZFn@8bytes.org> (raw)
In-Reply-To: <6c1785c8-e74e-4912-95bb-88b6e94f544f@intel.com>

On Thu, Jan 23, 2025 at 03:06:26PM -0800, Dave Hansen wrote:
> 32-bit+PTI or 32-bit in general? ;)

+1 for removing x86-32 bit support alltogether.

> I'm curious what Joerg and the other folks that worked on 32-bit PTI
> think about it in retrospect. The 32 vs. 64-bit security gap was
> probably modest in 2018 and it can only have grown since then.

I think the decision to keep and maintain 32-bit support only makes
sense if it can be kept on-par with x86-64 security-wise, otherwise we
are lying to our users about the 'supported' part. Back in the day when
I did the 32-bit PTI support it made sense, but that was 7 years ago.

When was the last 32-bit only x86 CPU sold?

> I definitely haven't seen a lot of 32-bit PTI bug reports.

That's because the 32-bit PTI support is a well crafted piece of beauty,
which was merged with almost no bugs ;-)


Regards,

	Joerg

  reply	other threads:[~2025-01-24  7:58 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-23 17:24 [RFC][PATCH 0/8] x86/mm: Simplify PAE page table handling Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 1/8] x86/mm: Always allocate a whole page for PAE PGDs Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 2/8] x86/mm: Always "broadcast" PMD setting operations Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 3/8] x86/mm: Always tell core mm to sync kernel mappings Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 4/8] x86/mm: Simplify PAE PGD sharing macros Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 5/8] x86/mm: Fix up comments around PMD preallocation Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 6/8] x86/mm: Preallocate all PAE page tables Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 7/8] x86/mm: Remove duplicated PMD preallocation macro Dave Hansen
2025-01-23 17:24 ` [RFC][PATCH 8/8] x86/mm: Remove now unused SHARED_KERNEL_PMD Dave Hansen
2025-01-23 21:49 ` [RFC][PATCH 0/8] x86/mm: Simplify PAE page table handling Peter Zijlstra
2025-01-23 23:06   ` Dave Hansen
2025-01-24  7:58     ` Joerg Roedel [this message]
2025-01-24 19:12       ` Dave Hansen
2025-01-28  8:13         ` Joerg Roedel
2025-01-24  8:52     ` Peter Zijlstra
2025-02-24 18:55 ` Ingo Molnar

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