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From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
To: andi@firstfloor.org
Cc: fujita.tomonori@lab.ntt.co.jp, mingo@elte.hu,
	joerg.roedel@amd.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] fix GART to respect device's dma_mask about virtual mappings
Date: Tue, 16 Sep 2008 22:20:40 +0900	[thread overview]
Message-ID: <20080916222032O.fujita.tomonori@lab.ntt.co.jp> (raw)
In-Reply-To: <87hc8grjuf.fsf@basil.nowhere.org>

On Tue, 16 Sep 2008 02:54:32 +0200
Andi Kleen <andi@firstfloor.org> wrote:

> FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> writes:
> 
> > Currently, gart IOMMU ignores device's dma_mask when it does virtual
> > mappings. So it could give a device a virtual address that the device
> > can't access to.
> 
> Huh? That is what the need_iommu() logic in gart_map_sg()
> does. An I'm not aware of any bugs in this area.

What the need_iommu() does is seeing if GART needs to do virtual
mappings or not.

(After need_iommu() checking) What this patchset does is to guarantee
that GART provides a virtual address that a device can access to.


> Did you actually see that failure in practice? I don't see
> how it could happen.

No, I did not. This patchset does the right thing theoretically, I
think, but if such problem never happens for GART, I'll drop the patch
for GART. Joerg?

  reply	other threads:[~2008-09-16 13:21 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-12 10:42 FUJITA Tomonori
2008-09-12 10:42 ` [PATCH 1/3] add iommu_device_max_index IOMMU helper function FUJITA Tomonori
2008-09-12 10:42   ` [PATCH 2/3] add dma_get_mask " FUJITA Tomonori
2008-09-12 10:42     ` [PATCH 3/3] x86: make GART to respect device's dma_mask about virtual mappings FUJITA Tomonori
2008-09-12 14:52       ` Joerg Roedel
2008-09-12 15:11         ` FUJITA Tomonori
2008-09-14 14:45 ` [PATCH 0/3] fix " Ingo Molnar
2008-09-16  0:54 ` Andi Kleen
2008-09-16 13:20   ` FUJITA Tomonori [this message]
2008-09-16 13:43     ` Andi Kleen
2008-09-16 17:13       ` FUJITA Tomonori
2008-09-16 17:58         ` Andi Kleen
2008-09-16 23:53           ` FUJITA Tomonori
2008-09-17  0:24             ` Andi Kleen
2008-09-17 19:20               ` FUJITA Tomonori
2008-09-18 18:20                 ` Andi Kleen
2008-09-18 22:15                   ` FUJITA Tomonori
2008-09-19  0:44                     ` Andi Kleen
2008-09-22 19:12                       ` FUJITA Tomonori
2008-09-22 20:35                         ` Andi Kleen
2008-09-23  4:02                           ` FUJITA Tomonori
2008-09-17 10:43             ` Ingo Molnar
2008-09-18 18:25               ` Andi Kleen
2008-09-16 15:52     ` Joerg Roedel
2008-09-16 16:20       ` Andi Kleen

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