From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org,
Wupeng Ma <mawupeng1@huawei.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v1] x86/mm/pat: fix VM_PAT handling in COW mappings
Date: Tue, 12 Mar 2024 19:22:56 +0000 [thread overview]
Message-ID: <ZfCrkL-Aieer2EAg@casper.infradead.org> (raw)
In-Reply-To: <20240312181118.318701-1-david@redhat.com>
On Tue, Mar 12, 2024 at 07:11:18PM +0100, David Hildenbrand wrote:
> PAT handling won't do the right thing in COW mappings: the first PTE
> (or, in fact, all PTEs) can be replaced during write faults to point at
> anon folios. Reliably recovering the correct PFN and cachemode using
> follow_phys() from PTEs will not work in COW mappings.
I guess the first question is: Why do we want to support COW mappings
of VM_PAT areas? What breaks if we just disallow it?
next prev parent reply other threads:[~2024-03-12 19:23 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 18:11 David Hildenbrand
2024-03-12 19:22 ` Matthew Wilcox [this message]
[not found] ` <5bc9de2f-c3ba-46e7-a234-3d3a46e53ba1@redhat.com>
2024-03-14 16:42 ` David Hildenbrand
2024-03-14 17:12 ` David Hildenbrand
2024-03-25 2:57 ` mawupeng
2024-03-26 8:33 ` Ingo Molnar
[not found] ` <922c5f99-1194-4118-9fe2-09b4f4a8cf04@redhat.com>
2024-03-26 8:53 ` Ingo Molnar
2024-03-26 8:57 ` David Hildenbrand
2024-04-01 9:45 ` Ingo Molnar
2024-04-02 9:14 ` David Hildenbrand
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