From: David Hildenbrand <david@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>, Fei Li <fei1.li@intel.com>,
x86@kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/3] virt: acrn: stop using follow_pfn
Date: Tue, 26 Mar 2024 18:06:50 +0100 [thread overview]
Message-ID: <e0bcac0d-b5bb-4356-aff8-5c077ab4c66f@redhat.com> (raw)
In-Reply-To: <20240326060447.GA7108@lst.de>
On 26.03.24 07:04, Christoph Hellwig wrote:
> On Mon, Mar 25, 2024 at 11:33:31AM +0100, David Hildenbrand wrote:
>> ... I have similar patches lying around here (see bwlow). I added some
>> actual access permission checks.
>>
>> (I also realized, that if we get an anon folio in a COW mapping via follow_pte()
>> here, I suspect one might be able to do some nasty things. Just imagine if we
>> munmap(), free the anon folio, and then it gets used in other context ... At
>> least KVM/vfio handle that using references+MMU notifiers.)
>
> How about you just send out your series that seems to go further and
> I retract mine?
Let's go with yours first and I'll rebase.
Regarding above issue, I still have not made up my mind: likely we
should reject any PFN in acrn that has a valid "struct page", and that
page does not have PG_reserved set. That's what VFIO effectively does IIRC.
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2024-03-26 17:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-24 23:45 remove follow_pfn Christoph Hellwig
2024-03-24 23:45 ` [PATCH 1/3] virt: acrn: stop using follow_pfn Christoph Hellwig
2024-03-25 10:33 ` David Hildenbrand
2024-03-26 6:04 ` Christoph Hellwig
2024-03-26 17:06 ` David Hildenbrand [this message]
2024-03-24 23:45 ` [PATCH 2/3] mm: remove follow_pfn Christoph Hellwig
2024-03-25 10:33 ` David Hildenbrand
2024-03-24 23:45 ` [PATCH 3/3] mm: move follow_phys to arch/x86/mm/pat/memtype.c Christoph Hellwig
2024-03-25 10:28 ` Ingo Molnar
2024-03-25 10:36 ` David Hildenbrand
2024-03-28 8:46 remove follow_pfn v2 Christoph Hellwig
2024-03-28 8:46 ` [PATCH 1/3] virt: acrn: stop using follow_pfn Christoph Hellwig
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