From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
the arch/x86 maintainers <x86@kernel.org>,
Kostya Serebryany <kcc@google.com>,
Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Taras Madan <tarasmadan@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
"H . J . Lu" <hjl.tools@gmail.com>,
Andi Kleen <ak@linux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Bharata B Rao <bharata@amd.com>,
Jacob Pan <jacob.jun.pan@linux.intel.com>,
Ashok Raj <ashok.raj@intel.com>, Linux-MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv14 04/17] x86/mm: Handle LAM on context switch
Date: Wed, 11 Jan 2023 17:14:59 +0300 [thread overview]
Message-ID: <20230111141459.ah7ijfbm733c4g7m@box.shutemov.name> (raw)
In-Reply-To: <CAHk-=whb1_6qwb=BSpj1KkTfJiTiahAnvTBh_=fnGyrnKAW19A@mail.gmail.com>
On Wed, Jan 11, 2023 at 07:49:30AM -0600, Linus Torvalds wrote:
> Sorry, I'm traveling, and right now only on mobile. So I'm reading patches
> on my phone, and answering on it too, so html garbage..
>
> On Wed, Jan 11, 2023, 07:24 Kirill A. Shutemov <
> kirill.shutemov@linux.intel.com> wrote:
>
> >
> > +static inline unsigned long mm_lam_cr3_mask(struct mm_struct *mm)
> > +{
> > + return READ_ONCE(mm->context.lam_cr3_mask);
> > +}
> >
>
> I mentioned this before - in the original version this needed (but didn't
> have, iirc) that READ_ONCE, but in the new non-thread situation I don't
> think that's true. There should be no concurrent changes that can interfere
> with the read, no?
It should be safe, yes.
It is reachable from iommu_sva_bind_device(), but it only called with mm
== current->mm.
I will drop the READ_ONCE().
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2023-01-11 14:15 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-11 12:37 [PATCHv14 00/17] Linear Address Masking enabling Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 01/17] x86/mm: Rework address range check in get_user() and put_user() Kirill A. Shutemov
2023-01-18 15:49 ` Peter Zijlstra
2023-01-18 15:59 ` Linus Torvalds
2023-01-18 16:48 ` Peter Zijlstra
2023-01-18 17:01 ` Linus Torvalds
2023-01-11 12:37 ` [PATCHv14 02/17] x86: Allow atomic MM_CONTEXT flags setting Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 03/17] x86: CPUID and CR3/CR4 flags for Linear Address Masking Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 04/17] x86/mm: Handle LAM on context switch Kirill A. Shutemov
2023-01-11 13:49 ` Linus Torvalds
2023-01-11 14:14 ` Kirill A. Shutemov [this message]
2023-01-11 14:37 ` [PATCHv14.1 " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 05/17] mm: Introduce untagged_addr_remote() Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 06/17] x86/uaccess: Provide untagged_addr() and remove tags before address check Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 07/17] x86/mm: Provide arch_prctl() interface for LAM Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 08/17] x86/mm: Reduce untagged_addr() overhead until the first LAM user Kirill A. Shutemov
2023-01-17 13:05 ` Peter Zijlstra
2023-01-17 13:57 ` Kirill A. Shutemov
2023-01-17 15:02 ` Peter Zijlstra
2023-01-17 17:18 ` Linus Torvalds
2023-01-17 17:28 ` Linus Torvalds
2023-01-17 18:26 ` Nick Desaulniers
2023-01-17 18:33 ` Linus Torvalds
2023-01-17 19:17 ` Nick Desaulniers
2023-01-17 20:10 ` Linus Torvalds
2023-01-17 20:43 ` Linus Torvalds
2023-01-17 18:14 ` Peter Zijlstra
2023-01-17 18:21 ` Peter Zijlstra
2023-01-19 23:06 ` Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 09/17] mm: Expose untagging mask in /proc/$PID/status Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 10/17] iommu/sva: Replace pasid_valid() helper with mm_valid_pasid() Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 11/17] x86/mm/iommu/sva: Make LAM and SVA mutually exclusive Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 12/17] selftests/x86/lam: Add malloc and tag-bits test cases for linear-address masking Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 13/17] selftests/x86/lam: Add mmap and SYSCALL " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 14/17] selftests/x86/lam: Add io_uring " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 15/17] selftests/x86/lam: Add inherit " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 16/17] selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA " Kirill A. Shutemov
2023-01-11 12:37 ` [PATCHv14 17/17] selftests/x86/lam: Add test cases for LAM vs thread creation Kirill A. Shutemov
2023-01-18 16:49 ` [PATCHv14 00/17] Linear Address Masking enabling Peter Zijlstra
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