From: robin.murphy@arm•com (Robin Murphy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 2/3] iommu/dma: Use correct offset in map_sg
Date: Mon, 4 Jan 2016 16:08:23 +0000 [thread overview]
Message-ID: <568A98F7.3050902@arm.com> (raw)
In-Reply-To: <20151228160551.GA17673@8bytes.org>
On 28/12/15 16:05, Joerg Roedel wrote:
> On Fri, Dec 18, 2015 at 05:01:47PM +0000, Robin Murphy wrote:
>> When mapping a non-page-aligned scatterlist entry, we copy the original
>> offset to the output DMA address before aligning it to hand off to
>> iommu_map_sg(), then later adding the IOVA page address portion to get
>> the final mapped address. However, when the IOVA page size is smaller
>> than the CPU page size, it is the offset within the IOVA page we want,
>> not that within the CPU page, which can easily be larger than an IOVA
>> page and thus result in an incorrect final address.
>>
>> Fix the bug by taking only the IOVA-aligned part of the offset as the
>> basis of the DMA address, not the whole thing.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@arm•com>
>> ---
>> drivers/iommu/dma-iommu.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index 982e716..03811e3 100644
>> --- a/drivers/iommu/dma-iommu.c
>> +++ b/drivers/iommu/dma-iommu.c
>> @@ -458,7 +458,7 @@ int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
>> size_t s_length = s->length;
>> size_t pad_len = (mask - iova_len + 1) & mask;
>>
>> - sg_dma_address(s) = s->offset;
>> + sg_dma_address(s) = s_offset;
>
> Does not apply on v4.4-rc7.
Ah, I did these on top of the map_sg tweak[1] locally, and failed to
spot that that leaks into a context line here. There's no actual
dependency so I'll rebase and repost this bugfix momentarily - as that
other thread seems to have stalled, I'll probably have another crack at
a proper scatterlist segment merging implementation sometime after the
merge window.
Thanks,
Robin.
[1]:http://thread.gmane.org/gmane.linux.kernel.iommu/11512
next prev parent reply other threads:[~2016-01-04 16:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-18 17:01 [PATCH 1/3] iommu/dma: Add some missing #includes Robin Murphy
2015-12-18 17:01 ` [PATCH 2/3] iommu/dma: Use correct offset in map_sg Robin Murphy
2015-12-28 16:05 ` Joerg Roedel
2016-01-04 16:08 ` Robin Murphy [this message]
2016-01-04 16:19 ` [PATCH RESEND] " Robin Murphy
2016-01-07 12:38 ` Joerg Roedel
2016-03-09 7:50 ` [PATCH 2/3] " Magnus Damm
2016-03-09 15:00 ` Robin Murphy
2016-03-10 7:47 ` Magnus Damm
2015-12-18 17:01 ` [PATCH 3/3] iommu/dma: Avoid unlikely high-order allocations Robin Murphy
2015-12-18 22:35 ` Doug Anderson
2016-01-19 2:55 ` Yong Wu
2015-12-28 16:08 ` [PATCH 1/3] iommu/dma: Add some missing #includes Joerg Roedel
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