From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
Will Deacon <will@kernel.org>,
"Ryan Roberts" <ryan.roberts@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>,
"Oliver Upton" <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
"Suzuki K Poulose" <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
"Andrey Ryabinin" <ryabinin.a.a@gmail.com>,
Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Matthew Wilcox <willy@infradead.org>, Yu Zhao <yuzhao@google.com>,
Mark Rutland <mark.rutland@arm.com>,
David Hildenbrand <david@redhat.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
John Hubbard <jhubbard@nvidia.com>, Zi Yan <ziy@nvidia.com>,
Barry Song <21cnbao@gmail.com>,
Alistair Popple <apopple@nvidia.com>,
Yang Shi <shy828301@gmail.com>,
<linux-arm-kernel@lists.infradead.org>, <linux-mm@kvack.org>,
<linux-kernel@vger.kernel.org>,
<shameerali.kolothum.thodi@huawei.com>
Subject: Re: [PATCH v3 12/15] arm64/mm: Split __flush_tlb_range() to elide trailing DSB
Date: Thu, 14 Dec 2023 16:45:41 +0000 [thread overview]
Message-ID: <20231214164541.000027a1@Huawei.com> (raw)
In-Reply-To: <20231214152206.GA3625745@myrica>
On Thu, 14 Dec 2023 15:22:06 +0000
Jean-Philippe Brucker <jean-philippe@linaro.org> wrote:
> On Thu, Dec 14, 2023 at 12:30:55PM +0000, Robin Murphy wrote:
> > > Robin, Jean-Philippe -- do we need to make sure that the SMMU has completed
> > > its TLB invalidation before issuing an ATC invalidate? My half-baked worry
> > > is whether or not an ATS request could refill the ATC before the TLBI
> > > has completed, therefore rendering the ATC invalidation useless.
> >
> > I would agree, and the spec for CMD_ATC_INV does call out a
> > TLBI->sync->ATCI->sync sequence. At the moment the SVA notifier is issuing
> > its own command-based TLBIs anyway so the necessary sync is implicit there,
> > but if and when we get BTM support wired up properly it would be nice not to
> > have to bodge in an additional sync/DSB.
>
> Yes agreed, with BTM the CPU must call the notifier that issues ATC
> invalidation after completing the TLBI+DSB instructions.
>
> SMMU IHI0070F.a 3.9.1 ATS Interface
>
> Software must ensure that the SMMU TLB invalidation is complete before
> initiating the ATC invalidation.
>
> I'm guessing BTM will be enabled in the SMMU driver sometime soon, given
> that there already is one implementation in the wild that could use it. I
> think we didn't enable it because of the lack of separation between shared
> and private VMIDs, but that may now be solvable with the recent rework of
> the VMID allocator.
>
+CC Shameer. We'll indeed need to fix this when enabling BTM.
Thanks for the heads up.
Jonathan
> Thanks,
> Jean
>
next prev parent reply other threads:[~2023-12-14 16:45 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-04 10:54 [PATCH v3 00/15] Transparent Contiguous PTEs for User Mappings Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 01/15] mm: Batch-copy PTE ranges during fork() Ryan Roberts
2023-12-04 15:47 ` David Hildenbrand
2023-12-04 16:00 ` David Hildenbrand
2023-12-04 17:27 ` David Hildenbrand
2023-12-05 11:30 ` Ryan Roberts
2023-12-05 12:04 ` David Hildenbrand
2023-12-05 14:16 ` Ryan Roberts
2023-12-08 0:32 ` Alistair Popple
2023-12-12 11:51 ` Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 02/15] mm: Batch-clear PTE ranges during zap_pte_range() Ryan Roberts
2023-12-08 1:30 ` Alistair Popple
2023-12-12 11:57 ` Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 03/15] arm64/mm: set_pte(): New layer to manage contig bit Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 04/15] arm64/mm: set_ptes()/set_pte_at(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 05/15] arm64/mm: pte_clear(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 06/15] arm64/mm: ptep_get_and_clear(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 07/15] arm64/mm: ptep_test_and_clear_young(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 08/15] arm64/mm: ptep_clear_flush_young(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 09/15] arm64/mm: ptep_set_wrprotect(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 10/15] arm64/mm: ptep_set_access_flags(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 11/15] arm64/mm: ptep_get(): " Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 12/15] arm64/mm: Split __flush_tlb_range() to elide trailing DSB Ryan Roberts
2023-12-12 11:35 ` Will Deacon
2023-12-12 11:47 ` Ryan Roberts
2023-12-14 11:53 ` Ryan Roberts
2023-12-14 12:13 ` Will Deacon
2023-12-14 12:30 ` Robin Murphy
2023-12-14 14:28 ` Ryan Roberts
2023-12-14 15:22 ` Jean-Philippe Brucker
2023-12-14 16:45 ` Jonathan Cameron [this message]
2023-12-04 10:54 ` [PATCH v3 13/15] arm64/mm: Wire up PTE_CONT for user mappings Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 14/15] arm64/mm: Implement ptep_set_wrprotects() to optimize fork() Ryan Roberts
2023-12-08 1:37 ` Alistair Popple
2023-12-12 11:59 ` Ryan Roberts
2023-12-15 4:32 ` Alistair Popple
2023-12-15 14:05 ` Ryan Roberts
2023-12-04 10:54 ` [PATCH v3 15/15] arm64/mm: Implement clear_ptes() to optimize exit() Ryan Roberts
2023-12-08 1:45 ` Alistair Popple
2023-12-12 12:02 ` Ryan Roberts
2023-12-05 3:41 ` [PATCH v3 00/15] Transparent Contiguous PTEs for User Mappings John Hubbard
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