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References: <20200711064846.16007-1-yong.wu@mediatek.com> <20200711064846.16007-7-yong.wu@mediatek.com>
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From:   Nicolas Boichat <drinkcat@chromium.org>
Date:   Mon, 13 Jul 2020 08:38:24 +0800
Message-ID: <CANMq1KAhFCWfywV=OiHgW00pof8K8TdwC6Hzgyj=QWSiWBf1ag@mail.gmail.com>
Subject: Re: [PATCH 06/21] iommu/io-pgtable-arm-v7s: Use ias to check the
 valid iova in unmap
To:     Yong Wu <yong.wu@mediatek.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will@kernel.org>,
        Evan Green <evgreen@chromium.org>,
        Tomasz Figa <tfiga@google.com>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@lists.infradead.org>,
        srv_heupstream <srv_heupstream@mediatek.com>,
        Devicetree List <devicetree@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        iommu@lists.linux-foundation.org, youlin.pei@mediatek.com,
        anan.sun@mediatek.com, cui.zhang@mediatek.com,
        chao.hao@mediatek.com, ming-fan.chen@mediatek.com
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On Sat, Jul 11, 2020 at 2:50 PM Yong Wu <yong.wu@mediatek.com> wrote:
>
> As title.
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
>  drivers/iommu/io-pgtable-arm-v7s.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> index 4272fe4e17f4..01f2a8876808 100644
> --- a/drivers/iommu/io-pgtable-arm-v7s.c
> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> @@ -717,7 +717,7 @@ static size_t arm_v7s_unmap(struct io_pgtable_ops *ops, unsigned long iova,
>  {
>         struct arm_v7s_io_pgtable *data = io_pgtable_ops_to_data(ops);
>
> -       if (WARN_ON(upper_32_bits(iova)))
> +       if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))

This is a little odd as iova is unsigned long and 1ULL is unsigned long long.

Would it be better to keep the spirit of the previous test and do
something like:
 if (WARN_ON(iova >> data->iop.cfg.ias)) ?

>                 return 0;
>
>         return __arm_v7s_unmap(data, gather, iova, size, 1, data->pgd);
> --
> 2.18.0