linux-kernel - Re: [PATCH v4 07/24] iommu/io-pgtable-arm-v7s: Use ias to check the valid iova in unmap

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Message-ID: <bf339a42-57af-6de2-aa04-816ebf205574@arm.com>
Date:   Thu, 26 Nov 2020 15:41:25 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Yong Wu <yong.wu@...iatek.com>, Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Rob Herring <robh+dt@...nel.org>, Will Deacon <will@...nel.org>
Cc:     Krzysztof Kozlowski <krzk@...nel.org>,
        Evan Green <evgreen@...omium.org>,
        Tomasz Figa <tfiga@...gle.com>,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org, youlin.pei@...iatek.com,
        Nicolas Boichat <drinkcat@...omium.org>, anan.sun@...iatek.com,
        chao.hao@...iatek.com, Greg Kroah-Hartman <gregkh@...gle.com>,
        kernel-team@...roid.com
Subject: Re: [PATCH v4 07/24] iommu/io-pgtable-arm-v7s: Use ias to check the
 valid iova in unmap

On 2020-11-11 12:38, Yong Wu wrote:
> Use the ias for the valid iova checking in arm_v7s_unmap. This is a
> preparing patch for supporting iova 34bit for MediaTek.

I can't help thinking of weird ways to generate better code here, but 
being consistent with what we already have on the map path is probably 
more valuable for now.

Reviewed-by: Robin Murphy <robin.murphy@....com>

> Signed-off-by: Yong Wu <yong.wu@...iatek.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 a688f22cbe3b..e880745ab1e8 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)))
>   		return 0;
>   
>   	return __arm_v7s_unmap(data, gather, iova, size, 1, data->pgd);
>