From: Linus Torvalds <torvalds@linux-foundation.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
Andy Lutomirsky <luto@kernel.org>,
Borislav Petkov <bpetkov@suse.de>,
Greg KH <gregkh@linuxfoundation.org>,
Kees Cook <keescook@google.com>, Hugh Dickins <hughd@google.com>,
Brian Gerst <brgerst@gmail.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Juergen Gross <jgross@suse.com>,
David Laight <David.Laight@aculab.com>,
Eduardo Valentin <eduval@amazon.com>,
"Liguori, Anthony" <aliguori@amazon.com>,
Will Deacon <will.deacon@arm.com>, linux-mm <linux-mm@kvack.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v2 01/17] mm/gup: Fixup p*_access_permitted()
Date: Fri, 15 Dec 2017 18:28:36 -0800 [thread overview]
Message-ID: <CA+55aFxcA4Ht2urZY+ZvaTHKDjOHH5NqPWHCrvZYnsG=EOx4jQ@mail.gmail.com> (raw)
In-Reply-To: <629d90d9-df33-2c31-e644-0bc356b61f25@intel.com>
On Fri, Dec 15, 2017 at 5:25 PM, Dave Hansen <dave.hansen@intel.com> wrote:
>
> I think the reason we needed VMA and PTE checks was the
> get_user_pages_fast() path not having a VMA.
That is indeed the point of get_user_pages_fast(): no vma lookup, no
locking, just "do the default case as streamlined as possible".
But part of it is also that we should fall back to the slow case if
the fast case doesn't work (eg because the page isn't there or
whatever).
So what we could do - perhaps - is to just make get_user_pages_fast()
check whether any of the protection key bits are set, and fail for
that case.
If we care, that is.
Linus
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next prev parent reply other threads:[~2017-12-16 2:28 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-14 11:27 [PATCH v2 00/17] x86/ldt: Use a VMA based read only mapping Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 01/17] mm/gup: Fixup p*_access_permitted() Peter Zijlstra
2017-12-14 12:41 ` Peter Zijlstra
2017-12-14 14:37 ` Peter Zijlstra
2017-12-14 20:44 ` Dave Hansen
2017-12-14 20:54 ` Peter Zijlstra
2017-12-14 21:18 ` Peter Zijlstra
2017-12-15 5:04 ` Dave Hansen
2017-12-15 6:09 ` Linus Torvalds
2017-12-15 7:51 ` Peter Zijlstra
2017-12-16 0:20 ` Linus Torvalds
2017-12-16 0:29 ` Dan Williams
2017-12-16 1:10 ` Linus Torvalds
2017-12-16 1:25 ` Dave Hansen
2017-12-16 2:28 ` Linus Torvalds [this message]
2017-12-16 2:48 ` Al Viro
2017-12-16 2:52 ` Linus Torvalds
2017-12-16 3:00 ` Linus Torvalds
2017-12-16 3:21 ` Dave Hansen
2017-12-16 1:29 ` Dan Williams
2017-12-16 0:31 ` Al Viro
2017-12-16 1:05 ` Linus Torvalds
2017-12-15 8:00 ` Peter Zijlstra
2017-12-15 10:25 ` Peter Zijlstra
2017-12-15 11:38 ` Peter Zijlstra
2017-12-15 16:38 ` Dan Williams
2017-12-18 11:54 ` Peter Zijlstra
2017-12-18 18:42 ` Dan Williams
2017-12-15 14:04 ` Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 02/17] mm: Exempt special mappings from mlock(), mprotect() and madvise() Peter Zijlstra
2017-12-14 16:19 ` Andy Lutomirski
2017-12-14 17:36 ` Peter Zijlstra
2018-01-02 16:44 ` Dmitry Safonov
2017-12-14 11:27 ` [PATCH v2 03/17] arch: Allow arch_dup_mmap() to fail Peter Zijlstra
2017-12-14 16:22 ` Andy Lutomirski
2017-12-14 11:27 ` [PATCH v2 04/17] x86/ldt: Rework locking Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 05/17] x86/ldt: Prevent ldt inheritance on exec Peter Zijlstra
2017-12-14 16:32 ` Andy Lutomirski
2017-12-14 11:27 ` [PATCH v2 06/17] x86/ldt: Do not install LDT for kernel threads Peter Zijlstra
2017-12-14 19:43 ` Peter Zijlstra
2017-12-14 21:27 ` Andy Lutomirski
2017-12-14 11:27 ` [PATCH v2 07/17] mm/softdirty: Move VM_SOFTDIRTY into high bits Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 08/17] mm/x86: Allow special mappings with user access cleared Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 09/17] mm: Provide vm_special_mapping::close Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 10/17] selftest/x86: Implement additional LDT selftests Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 11/17] selftests/x86/ldt_gdt: Prepare for access bit forced Peter Zijlstra
2017-12-14 16:20 ` Andy Lutomirski
2017-12-14 19:43 ` Linus Torvalds
2017-12-14 21:22 ` Andy Lutomirski
2017-12-14 21:44 ` Linus Torvalds
2017-12-14 21:48 ` Linus Torvalds
2017-12-14 22:02 ` Peter Zijlstra
2017-12-14 22:14 ` Linus Torvalds
2017-12-14 22:24 ` Peter Zijlstra
2017-12-14 22:52 ` Linus Torvalds
2017-12-14 22:11 ` Andy Lutomirski
2017-12-14 22:15 ` Linus Torvalds
2017-12-14 22:30 ` Andy Lutomirski
2017-12-14 22:23 ` Thomas Gleixner
2017-12-14 22:50 ` Linus Torvalds
2017-12-14 11:27 ` [PATCH v2 12/17] mm: Make populate_vma_page_range() available Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 13/17] x86/mm: Force LDT desc accessed bit Peter Zijlstra
2017-12-14 16:21 ` Andy Lutomirski
2017-12-14 11:27 ` [PATCH v2 14/17] x86/ldt: Reshuffle code Peter Zijlstra
2017-12-14 16:23 ` Andy Lutomirski
2017-12-14 16:31 ` Thomas Gleixner
2017-12-14 16:32 ` Thomas Gleixner
2017-12-14 16:34 ` Andy Lutomirski
2017-12-14 17:47 ` Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 15/17] x86/ldt: Prepare for VMA mapping Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 16/17] x86/ldt: Add VMA management code Peter Zijlstra
2017-12-14 11:27 ` [PATCH v2 17/17] x86/ldt: Make it read only VMA mapped Peter Zijlstra
2017-12-14 12:03 ` [PATCH v2 00/17] x86/ldt: Use a VMA based read only mapping Thomas Gleixner
2017-12-14 12:08 ` Peter Zijlstra
2017-12-14 16:35 ` Andy Lutomirski
2017-12-14 17:50 ` Peter Zijlstra
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