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Date:   Thu, 23 Jun 2022 11:38:34 +0800
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Cc:     baolu.lu@linux.intel.com, Steve Wahl <steve.wahl@hpe.com>,
        Joerg Roedel <jroedel@suse.de>,
        Kyung Min Park <kyung.min.park@intel.com>,
        David Woodhouse <dwmw2@infradead.org>,
        Will Deacon <will@kernel.org>,
        iommu <iommu@lists.linux-foundation.org>,
        Kevin Tian <kevin.tian@intel.com>,
        Mike Travis <mike.travis@hpe.com>,
        Dimitri Sivanich <sivanich@hpe.com>,
        Russ Anderson <russ.anderson@hpe.com>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] iommu/vt-d: Make DMAR_UNITS_SUPPORTED a config setting
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To:     Jerry Snitselaar <jsnitsel@redhat.com>
References: <9d6177ac-802f-eb11-4307-b0e49d8126b5@linux.intel.com>
 <20220615183650.32075-1-steve.wahl@hpe.com>
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From:   Baolu Lu <baolu.lu@linux.intel.com>
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On 2022/6/23 10:51, Jerry Snitselaar wrote:
>> The real problem here is that the iommu sequence ID overflows if
>> DMAR_UNITS_SUPPORTED is not big enough. This is purely a software
>> implementation issue, I am not sure whether user opt-in when building a
>> kernel package could help a lot here.
>>
> Is this something that could be figured out when parsing the dmar
> table? It looks like currently iommu_refcnt[], iommu_did[], and
> dmar_seq_ids[] depend on it.

That's definitely a better solution.

Best regards,
baolu