Messages in this thread | | | From | Casey Leedom <> | Subject | Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU | Date | Wed, 27 Sep 2017 16:31:04 +0000 |
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| From: Dan Williams <dan.j.williams@intel.com> | Sent: Tuesday, September 26, 2017 9:10 AM | | On Tue, Sep 26, 2017 at 9:06 AM, Casey Leedom <leedom@chelsio.com> wrote: | > | From: Robin Murphy <robin.murphy@arm.com> | > | Sent: Tuesday, September 26, 2017 7:22 AM | > |... | > ... | > Regardless, it seems that you agree that there's an issue with the Intel | > I/O MMU support code with regard to the legal values which a (struct | > scatterlist) can take on? I still can't find any documentation for this | > and, personally, I'm a bit baffled by a Page-oriented Scatter/Gather List | > representation where [Offset, Offset+Length) can reside outside the Page. | | Consider the case where the page represents a huge page, then an | offset greater than PAGE_SIZE (up to HPAGE_SIZE) makes sense.
Okay, but whatever the underlaying Page Size is, should [Offset, Offset+Length) completely reside within the referenced Page? I'm just trying to understand the Invariance Conditions which are assumed by all of the code which processes Scatter/gather Lists ...
Casey
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