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Date:   Fri, 1 Dec 2023 16:48:18 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Tina Zhang <tina.zhang@intel.com>
Cc:     iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
        David Woodhouse <dwmw2@infradead.org>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Kevin Tian <kevin.tian@intel.com>,
        Nicolin Chen <nicolinc@nvidia.com>,
        Michael Shavit <mshavit@google.com>,
        Vasant Hegde <vasant.hegde@amd.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Raj Ashok <ashok.raj@intel.com>, Yi Liu <yi.l.liu@intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        torvalds@linux-foundation.org,
        Jacob Pan <jacob.jun.pan@linux.intel.com>
Subject: Re: [PATCH] iommu: Change kconfig around IOMMU_SVA
Message-ID: <20231201204818.GH1489931@ziepe.ca>
References: <20231128021635.5530-1-tina.zhang@intel.com>
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On Tue, Nov 28, 2023 at 10:16:35AM +0800, Tina Zhang wrote:
> From: Jason Gunthorpe <jgg@nvidia.com>
> 
> Linus suggested that the kconfig here is confusing:
> 
> https://lore.kernel.org/all/CAHk-=wgUiAtiszwseM1p2fCJ+sC4XWQ+YN4TanFhUgvUqjr9Xw@mail.gmail.com/
> 
> Let's break it into three kconfigs controlling distinct things:
> 
>  - CONFIG_IOMMU_MM_DATA controls if the mm_struct has the additional
>    fields for the IOMMU. Currently only PASID, but later patches store
>    a struct iommu_mm_data *
> 
>  - CONFIG_ARCH_HAS_CPU_PASID controls if the arch needs the scheduling bit
>    for keeping track of the ENQCMD instruction. x86 will select this if
>    IOMMU_SVA is enabled
> 
>  - IOMMU_SVA controls if the IOMMU core compiles in the SVA support code
>    for iommu driver use and the IOMMU exported API
> 
> This way ARM will not enable CONFIG_ARCH_HAS_CPU_PASID
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Tina Zhang <tina.zhang@intel.com>
> ---
>  arch/Kconfig             | 5 +++++
>  arch/x86/Kconfig         | 1 +
>  arch/x86/kernel/traps.c  | 2 +-
>  drivers/iommu/Kconfig    | 1 +
>  include/linux/iommu.h    | 2 +-
>  include/linux/mm_types.h | 2 +-
>  include/linux/sched.h    | 2 +-
>  kernel/fork.c            | 2 +-
>  mm/Kconfig               | 3 +++
>  mm/init-mm.c             | 2 +-
>  10 files changed, 16 insertions(+), 6 deletions(-)

Try again, you need to cc the mm list and the x86 list

Jason