linux-kernel - Re: [PATCH v1 6/7] iommu/arm-smmu-v3: Refactor write_ctx

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Message-ID: <CAKHBV24bEYboxv9XXPvgt86q2B2DTm2He-mbO=kJqsNijCmMMg@mail.gmail.com>
Date:   Fri, 28 Jul 2023 15:34:40 +0800
From:   Michael Shavit <mshavit@...gle.com>
To:     Nicolin Chen <nicolinc@...dia.com>
Cc:     Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>, jean-philippe@...aro.org,
        jgg@...dia.com, baolu.lu@...ux.intel.com,
        linux-arm-kernel@...ts.infradead.org, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 6/7] iommu/arm-smmu-v3: Refactor write_ctx_desc

On Fri, Jul 28, 2023 at 5:38 AM Nicolin Chen <nicolinc@...dia.com> wrote:
> > @@ -1101,11 +1094,11 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
> >                 cdptr[3] = cpu_to_le64(cd->mair);
> >
> >                 /*
> > -                * STE is live, and the SMMU might read dwords of this CD in any
> > -                * order. Ensure that it observes valid values before reading
> > -                * V=1.
> > +                * STE may be live, and the SMMU might read dwords of this CD
> > +                * in any order. Ensure that it observes valid values before
> > +                * reading V=1.
>
> This seems to be true only after the following patch? If so, we
> should move this part over there too.

This comment is more in theme with the next commit so I can move it
over. But FWIW, the fact that the STE is not necessarily live at this
location is true before this patch, in this patch, and after the
following patch. Fixing this comment is just a drive-by, not a result
of any of these changes.