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Message-ID: <e0a570c3-4145-8413-cb7a-e4313819ae1b@linux.intel.com>
Date:   Tue, 9 May 2023 09:55:34 +0800
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Cc:     baolu.lu@linux.intel.com, Jason Gunthorpe <jgg@nvidia.com>,
        LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Joerg Roedel <joro@8bytes.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will@kernel.org>, Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        "Hansen, Dave" <dave.hansen@intel.com>,
        Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Subject: Re: [PATCH] iommu: Add Kconfig help text for IOMMU_SVA
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To:     Jacob Pan <jacob.jun.pan@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
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From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20230508132130.5a6feb0b@jacob-builder>
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On 5/9/23 4:21 AM, Jacob Pan wrote:
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index db98c3f86e8c..7106f3af74ee 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -153,9 +153,13 @@ config IOMMU_DMA
>   	select IRQ_MSI_IOMMU
>   	select NEED_SG_DMA_LENGTH
>   
> +config IOMMU_MM_PASID
> +	bool
> +
>   # Shared Virtual Addressing
>   config IOMMU_SVA
>   	bool
> +	select IOMMU_MM_PASID
>   
>   config FSL_PAMU
>   	bool "Freescale IOMMU support"
> diff --git a/drivers/iommu/intel/Kconfig b/drivers/iommu/intel/Kconfig
> index 2e56bd79f589..b4d7bd68a911 100644
> --- a/drivers/iommu/intel/Kconfig
> +++ b/drivers/iommu/intel/Kconfig
> @@ -50,6 +50,7 @@ config INTEL_IOMMU_SVM
>   	depends on X86_64
>   	select MMU_NOTIFIER
>   	select IOMMU_SVA
> +	select IOMMU_MM_PASID

IOMMU_SVA has already selected IOMMU_MM_PASID, so there's no need to
select it again here?

IOMMU_SVA selects IOMMU_MM_PASID, the vt-d driver itself has no need to
know about this.

>   	help
>   	  Shared Virtual Memory (SVM) provides a facility for devices
>   	  to access DMA resources through process address space by

Best regards,
baolu