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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 8 May 2023 09:42:18 -0700
Message-ID: <CAHk-=wgobPe0U=Sc-PH08vF-ZbG00KrzftEpQMQ=n0LLNn7y6A@mail.gmail.com>
Subject: Re: [PATCH] iommu: Add Kconfig help text for IOMMU_SVA
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Jason Gunthorpe <jgg@nvidia.com>,
        Lu Baolu <baolu.lu@linux.intel.com>,
        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>
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On Mon, May 8, 2023 at 9:35=E2=80=AFAM Jacob Pan <jacob.jun.pan@linux.intel=
.com> wrote:
>
> Conversely, we could also have some part of PASID that is not about SVA.

If that's the case, then we should *definitely* have that IOMMU_PASID
kind of config option.

Then IOMMU_SVA - that needs PASID - can "select" it, but any other use
- that doesn't bother about SVA but might want PASID for its own
nefarious purposes - can also select it.

This is why we have config options. Not just for legibility, but also
for "there are different scenarios".

                Linus