From: Jean-Philippe Brucker <jean-philippe@linaro.org>
To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
Cc: "fenghua.yu@intel.com" <fenghua.yu@intel.com>,
"will@kernel.org" <will@kernel.org>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"zhangfei.gao@linaro.org" <zhangfei.gao@linaro.org>,
"robin.murphy@arm.com" <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v10 10/13] iommu/arm-smmu-v3: Check for SVA features
Date: Thu, 24 Sep 2020 12:13:40 +0200 [thread overview]
Message-ID: <20200924101340.GC170808@myrica> (raw)
In-Reply-To: <753bcd76c21c4ea98ef1d4e492db01f4@huawei.com>
Hi Shameer,
On Mon, Sep 21, 2020 at 08:59:39AM +0000, Shameerali Kolothum Thodi wrote:
> > +bool arm_smmu_sva_supported(struct arm_smmu_device *smmu)
> > +{
> > + unsigned long reg, fld;
> > + unsigned long oas;
> > + unsigned long asid_bits;
> > + u32 feat_mask = ARM_SMMU_FEAT_BTM |
> > ARM_SMMU_FEAT_COHERENCY;
>
> Why is BTM mandated for SVA? I couldn't find this requirement in SMMU spec
> (Sorry if I missed it or this got discussed earlier). But if performance is the only concern here,
> is it better just to allow it with a warning rather than limiting SMMUs without BTM?
It's a performance concern and requires to support multiple
configurations, but the spec allows it. Are there SMMUs without BTM that
need it?
Thanks,
Jean
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next prev parent reply other threads:[~2020-09-24 10:14 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 10:18 [PATCH v10 00/13] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part) Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 01/13] mm: Define pasid in mm Jean-Philippe Brucker
2020-09-28 22:22 ` Will Deacon
2020-09-28 22:43 ` Fenghua Yu
2020-09-30 9:13 ` Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 02/13] iommu/ioasid: Add ioasid references Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 03/13] iommu/sva: Add PASID helpers Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 04/13] arm64: mm: Pin down ASIDs for sharing mm with devices Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 05/13] iommu/io-pgtable-arm: Move some definitions to a header Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 06/13] arm64: cpufeature: Export symbol read_sanitised_ftr_reg() Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 07/13] iommu/arm-smmu-v3: Move definitions to a header Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 08/13] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2020-09-18 10:18 ` [PATCH v10 09/13] iommu/arm-smmu-v3: Seize private ASID Jean-Philippe Brucker
2020-09-18 13:07 ` Jonathan Cameron
2020-09-18 10:18 ` [PATCH v10 10/13] iommu/arm-smmu-v3: Check for SVA features Jean-Philippe Brucker
2020-09-21 8:59 ` Shameerali Kolothum Thodi
2020-09-24 10:13 ` Jean-Philippe Brucker [this message]
2020-09-24 11:13 ` Shameerali Kolothum Thodi
2020-12-09 19:49 ` Krishna Reddy
2020-12-09 20:07 ` Will Deacon
2020-12-09 20:38 ` Krishna Reddy
2020-12-14 9:32 ` Jean-Philippe Brucker
2020-12-14 23:23 ` Krishna Reddy
2020-09-18 10:18 ` [PATCH v10 11/13] iommu/arm-smmu-v3: Add SVA device feature Jean-Philippe Brucker
2020-12-15 1:09 ` Krishna Reddy
2021-01-06 10:09 ` Jean-Philippe Brucker
2021-01-06 17:23 ` Krishna Reddy
2020-09-18 10:18 ` [PATCH v10 12/13] iommu/arm-smmu-v3: Implement iommu_sva_bind/unbind() Jean-Philippe Brucker
2020-11-24 23:58 ` Jason Gunthorpe
2020-11-25 9:27 ` Jean-Philippe Brucker
2020-11-26 0:37 ` Jason Gunthorpe
2020-09-18 10:18 ` [PATCH v10 13/13] iommu/arm-smmu-v3: Hook up ATC invalidation to mm ops Jean-Philippe Brucker
2020-09-18 13:15 ` [PATCH v10 00/13] iommu: Shared Virtual Addressing for SMMUv3 (PT sharing part) Jonathan Cameron
2020-09-28 16:47 ` Jean-Philippe Brucker
2020-09-28 17:23 ` Will Deacon
2020-09-28 22:39 ` Will Deacon
2020-09-30 9:12 ` Jean-Philippe Brucker
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