From: Joerg Roedel <joro@8bytes.org>
To: honghui.zhang@mediatek.com
Cc: treding@nvidia.com, mark.rutland@arm.com, matthias.bgg@gmail.com,
robh@kernel.org, robin.murphy@arm.com, p.zabel@pengutronix.de,
devicetree@vger.kernel.org, pebolle@tiscali.nl,
kendrick.hsu@mediatek.com, arnd@arndb.de,
srv_heupstream@mediatek.com, catalin.marinas@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org,
tfiga@google.com, iommu@lists.linux-foundation.org,
robh+dt@kernel.org, djkurtz@google.com, kernel@pengutronix.de,
linux-mediatek@lists.infradead.org,
linux-arm-kernel@lists.infradead.org, l.stach@pengutronix.de,
yingjoe.chen@mediatek.com, eddie.huang@mediatek.com,
youlin.pei@mediatek.com, erin.lo@mediatek.com
Subject: Re: [RFC PATCH] iommu: create direct_mapping after device attached
Date: Wed, 20 Jul 2016 16:01:27 +0200 [thread overview]
Message-ID: <20160720140127.GA3030@8bytes.org> (raw)
In-Reply-To: <1469018961-16367-1-git-send-email-honghui.zhang@mediatek.com>
On Wed, Jul 20, 2016 at 08:49:21PM +0800, honghui.zhang@mediatek.com wrote:
> From: Honghui Zhang <honghui.zhang@mediatek.com>
>
> For mtk iommu, the domain_finalize was called in device attatch, the mtk
> iommu iopgt ops was allocated and initialized in domain_finalize, the
> iommu_group_create_direct_mappings would call the map interface to
> implement the map. If it's earlier than device attach, there would be NULL
> dereference. Move the iommu_group_create_direct_mappings call after device
> attached.
No, this would open a race window where the device is attached, but
doesn't have its unity-mappings in place. You should re-organize the mtk
driver instead, so that it works in this order too.
Joerg
WARNING: multiple messages have this Message-ID (diff)
From: joro@8bytes.org (Joerg Roedel)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] iommu: create direct_mapping after device attached
Date: Wed, 20 Jul 2016 16:01:27 +0200 [thread overview]
Message-ID: <20160720140127.GA3030@8bytes.org> (raw)
In-Reply-To: <1469018961-16367-1-git-send-email-honghui.zhang@mediatek.com>
On Wed, Jul 20, 2016 at 08:49:21PM +0800, honghui.zhang at mediatek.com wrote:
> From: Honghui Zhang <honghui.zhang@mediatek.com>
>
> For mtk iommu, the domain_finalize was called in device attatch, the mtk
> iommu iopgt ops was allocated and initialized in domain_finalize, the
> iommu_group_create_direct_mappings would call the map interface to
> implement the map. If it's earlier than device attach, there would be NULL
> dereference. Move the iommu_group_create_direct_mappings call after device
> attached.
No, this would open a race window where the device is attached, but
doesn't have its unity-mappings in place. You should re-organize the mtk
driver instead, so that it works in this order too.
Joerg
next prev parent reply other threads:[~2016-07-20 14:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-20 12:49 [RFC PATCH] iommu: create direct_mapping after device attached honghui.zhang-NuS5LvNUpcJWk0Htik3J/w
2016-07-20 12:49 ` honghui.zhang
2016-07-20 12:49 ` honghui.zhang at mediatek.com
2016-07-20 14:01 ` Joerg Roedel [this message]
2016-07-20 14:01 ` Joerg Roedel
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