linux-mediatek.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
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)
> 

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1608171967.26323.211.camel@mhfsdcap03 \
    --to=yong.wu@mediatek.com \
    --cc=David.Laight@ACULAB.COM \
    --cc=anan.sun@mediatek.com \
    --cc=chao.hao@mediatek.com \
    --cc=drinkcat@chromium.org \
    --cc=gregkh@google.com \
    --cc=iommu@lists.linux-foundation.org \
    --cc=joro@8bytes.org \
    --cc=kernel-team@android.com \
    --cc=krzk@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=matthias.bgg@gmail.com \
    --cc=robin.murphy@arm.com \
    --cc=srv_heupstream@mediatek.com \
    --cc=tfiga@google.com \
    --cc=will@kernel.org \
    --cc=youlin.pei@mediatek.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).