From: Will Deacon <will@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: devicetree@vger.kernel.org, kevin.tian@intel.com, maz@kernel.org,
jgg@ziepe.ca, linux-pci@vger.kernel.org, fenghua.yu@intel.com,
hch@infradead.org, linux-mm@kvack.org,
iommu@lists.linux-foundation.org, zhangfei.gao@linaro.org,
catalin.marinas@arm.com, felix.kuehling@amd.com,
robin.murphy@arm.com, christian.koenig@amd.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v7 13/24] iommu/arm-smmu-v3: Enable broadcast TLB maintenance
Date: Thu, 21 May 2020 15:17:31 +0100 [thread overview]
Message-ID: <20200521141730.GJ6608@willie-the-truck> (raw)
In-Reply-To: <20200519175502.2504091-14-jean-philippe@linaro.org>
[+Marc]
On Tue, May 19, 2020 at 07:54:51PM +0200, Jean-Philippe Brucker wrote:
> The SMMUv3 can handle invalidation targeted at TLB entries with shared
> ASIDs. If the implementation supports broadcast TLB maintenance, enable it
> and keep track of it in a feature bit. The SMMU will then be affected by
> inner-shareable TLB invalidations from other agents.
>
> A major side-effect of this change is that stage-2 translation contexts
> are now affected by all invalidations by VMID. VMIDs are all shared and
> the only ways to prevent over-invalidation, since the stage-2 page tables
> are not shared between CPU and SMMU, are to either disable BTM or allocate
> different VMIDs. This patch does not address the problem.
This sounds like a potential performance issue, particularly as we expose
stage-2 contexts via VFIO directly. Maybe we could reserve some portion of
VMID space for the SMMU? Marc, what do you reckon?
Will
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next prev parent reply other threads:[~2020-05-21 14:17 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 17:54 [PATCH v7 00/24] iommu: Shared Virtual Addressing for SMMUv3 Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 01/24] mm: Add a PASID field to mm_struct Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 02/24] iommu/ioasid: Add ioasid references Jean-Philippe Brucker
2020-05-20 2:31 ` Lu Baolu
2020-05-19 17:54 ` [PATCH v7 03/24] iommu/sva: Add PASID helpers Jean-Philippe Brucker
2020-05-20 2:41 ` Lu Baolu
2020-05-19 17:54 ` [PATCH v7 04/24] iommu: Add a page fault handler Jean-Philippe Brucker
2020-05-20 6:42 ` Lu Baolu
2020-11-11 13:57 ` Jean-Philippe Brucker
2020-11-11 23:11 ` Lu Baolu
2020-05-29 9:18 ` Xiang Zheng
2020-11-11 13:57 ` Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 05/24] arm64: mm: Add asid_gen_match() helper Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 06/24] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 07/24] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-05-21 14:16 ` Will Deacon
2020-05-19 17:54 ` [PATCH v7 08/24] iommu/arm-smmu-v3: Manage ASIDs with xarray Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 09/24] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 10/24] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 11/24] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 12/24] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2020-05-21 14:16 ` Will Deacon
2020-05-19 17:54 ` [PATCH v7 13/24] iommu/arm-smmu-v3: Enable broadcast TLB maintenance Jean-Philippe Brucker
2020-05-21 14:17 ` Will Deacon [this message]
2020-05-21 14:38 ` Marc Zyngier
2020-05-22 10:17 ` Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 14/24] iommu/arm-smmu-v3: Add SVA feature checking Jean-Philippe Brucker
2020-05-21 14:17 ` Will Deacon
2020-05-19 17:54 ` [PATCH v7 15/24] iommu/arm-smmu-v3: Add SVA device feature Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 16/24] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 17/24] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 18/24] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update Jean-Philippe Brucker
2020-05-21 11:12 ` Will Deacon
2020-05-27 3:00 ` Xiang Zheng
2020-05-27 8:41 ` Jean-Philippe Brucker
2020-08-28 9:28 ` Zenghui Yu
2020-09-16 14:11 ` Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 19/24] iommu/arm-smmu-v3: Maintain a SID->device structure Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 20/24] dt-bindings: document stall property for IOMMU masters Jean-Philippe Brucker
2020-05-19 17:54 ` [PATCH v7 21/24] iommu/arm-smmu-v3: Add stall support for platform devices Jean-Philippe Brucker
2020-06-01 12:42 ` Shameerali Kolothum Thodi
2020-06-02 9:38 ` Jean-Philippe Brucker
2020-06-02 10:31 ` Shameerali Kolothum Thodi
2020-06-02 11:46 ` Jean-Philippe Brucker
2020-06-02 12:12 ` Shameerali Kolothum Thodi
2020-06-03 7:38 ` Jean-Philippe Brucker
2020-05-19 17:55 ` [PATCH v7 22/24] PCI/ATS: Add PRI stubs Jean-Philippe Brucker
2020-05-19 17:55 ` [PATCH v7 23/24] PCI/ATS: Export PRI functions Jean-Philippe Brucker
2020-05-19 17:55 ` [PATCH v7 24/24] iommu/arm-smmu-v3: Add support for PRI Jean-Philippe Brucker
2020-05-21 10:35 ` [PATCH v7 00/24] iommu: Shared Virtual Addressing for SMMUv3 Will Deacon
2020-05-21 14:17 ` Will Deacon
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