From: Yong Wu <yong.wu@mediatek.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: "youlin.pei@mediatek.com" <youlin.pei@mediatek.com>,
"anan.sun@mediatek.com" <anan.sun@mediatek.com>,
Nicolas Boichat <drinkcat@chromium.org>,
"srv_heupstream@mediatek.com" <srv_heupstream@mediatek.com>,
"chao.hao@mediatek.com" <chao.hao@mediatek.com>,
Will Deacon <will@kernel.org>, Joerg Roedel <joro@8bytes.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
Tomasz Figa <tfiga@google.com>,
"iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-mediatek@lists.infradead.org"
<linux-mediatek@lists.infradead.org>,
Matthias Brugger <matthias.bgg@gmail.com>,
"kernel-team@android.com" <kernel-team@android.com>,
Greg Kroah-Hartman <gregkh@google.com>,
Robin Murphy <robin.murphy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 4/7] iommu: Switch gather->end to unsigned long long
Date: Thu, 17 Dec 2020 10:26:07 +0800 [thread overview]
Message-ID: <1608171967.26323.211.camel@mhfsdcap03> (raw)
In-Reply-To: <6b4a1d37a90f4663adf6b4adb9f80e2b@AcuMS.aculab.com>
Hi David,
On Wed, 2020-12-16 at 11:03 +0000, David Laight wrote:
> From: Yong Wu
> > Sent: 16 December 2020 10:36
> >
> > Currently gather->end is "unsigned long" which may be overflow in
> > arch32 in the corner case: 0xfff00000 + 0x100000(iova + size).
> > Although it doesn't affect the size(end - start), it affects the checking
> > "gather->end < end"
> >
> > Fixes: a7d20dc19d9e ("iommu: Introduce struct iommu_iotlb_gather for batching TLB flushes")
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---
> > include/linux/iommu.h | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 794d4085edd3..6e907a95d981 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -178,7 +178,7 @@ enum iommu_dev_features {
> > */
> > struct iommu_iotlb_gather {
> > unsigned long start;
> > - unsigned long end;
> > + unsigned long long end;
> > size_t pgsize;
> > };
>
> Doesn't that add two pad words on many 32bit systems?
> You probably ought to re-order the structure to keep the fields
> on their natural boundaries.
>
> I'm not sure what is being mapped here, but could it make sense
> to just avoid using the highest addresses?
> Then you never hit the problem.
Thanks for your review. following Robin's suggesting, I will use "iova +
size - 1", then avoid this.
>
> David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>
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next prev parent reply other threads:[~2020-12-17 2:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-16 10:36 [PATCH v3 0/7] MediaTek IOMMU improve tlb flush performance in map/unmap Yong Wu
2020-12-16 10:36 ` [PATCH v3 1/7] iommu: Move iotlb_sync_map out from __iommu_map Yong Wu
2020-12-23 8:51 ` Christoph Hellwig
2020-12-24 11:27 ` Yong Wu
2020-12-16 10:36 ` [PATCH v3 2/7] iommu: Add iova and size as parameters in iotlb_sync_map Yong Wu
2020-12-16 10:36 ` [PATCH v3 3/7] iommu/mediatek: Add iotlb_sync_map to sync whole the iova range Yong Wu
2020-12-16 10:36 ` [PATCH v3 4/7] iommu: Switch gather->end to unsigned long long Yong Wu
2020-12-16 11:03 ` David Laight
2020-12-17 2:26 ` Yong Wu [this message]
2020-12-16 12:10 ` Robin Murphy
2020-12-17 2:26 ` Yong Wu
2020-12-16 10:36 ` [PATCH v3 5/7] iommu: Allow io_pgtable_tlb ops optional Yong Wu
2021-01-18 16:18 ` Robin Murphy
2020-12-16 10:36 ` [PATCH v3 6/7] iommu/mediatek: Gather iova in iommu_unmap to achieve tlb sync once Yong Wu
2020-12-23 8:56 ` Tomasz Figa
2020-12-23 11:00 ` Robin Murphy
2021-01-08 9:56 ` Tomasz Figa
2021-01-08 9:56 ` Tomasz Figa
2021-01-18 16:35 ` Robin Murphy
2021-01-18 16:58 ` Will Deacon
2021-01-18 17:14 ` Robin Murphy
2020-12-16 10:36 ` [PATCH v3 7/7] iommu/mediatek: Remove the tlb-ops for v7s Yong Wu
2021-01-18 16:39 ` Robin Murphy
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