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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Wed, 9 Dec 2020 10:07:46 -0800
Message-ID: <CAHk-=wht4inbTVVMt2TNDxR_cVjSNaBU3JYyKtRMVovWePb65g@mail.gmail.com>
Subject: Re: [GIT PULL] IOMMU fix for 5.10 (-final)
To:     Will Deacon <will@kernel.org>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc:     iommu <iommu@lists.linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Lu Baolu <baolu.lu@linux.intel.com>
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On Wed, Dec 9, 2020 at 6:12 AM Will Deacon <will@kernel.org> wrote:
>
> Please pull this one-liner AMD IOMMU fix for 5.10. It's actually a fix
> for a fix, where the size of the interrupt remapping table was increased
> but a related constant for the size of the interrupt table was forgotten.

Pulled.

However, why didn't this then add some sanity checking for the two
different #defines to be in sync?

IOW, something like

   #define AMD_IOMMU_IRQ_TABLE_SHIFT 9

   #define MAX_IRQS_PER_TABLE (1 << AMD_IOMMU_IRQ_TABLE_SHIFT)
   #define DTE_IRQ_TABLE_LEN ((u64)AMD_IOMMU_IRQ_TABLE_SHIFT << 1)

or whatever. Hmm?

That way this won't happen again, but perhaps equally importantly the
linkage will be more clear, and there won't be those random constants.

Naming above is probably garbage - I assume there's some actual
architectural name for that irq table length field in the DTE?

         Linus