Re: DMA error when sg->offset value is greater than PAGE_SIZE in Intel IOMMU

[Harsh Jain]

On 26-09-2017 01:41, Dan Williams wrote:
> On Mon, Sep 25, 2017 at 1:05 PM, Casey Leedom <leedom@xxxxxxxxxxx> wrote:
>> | From: Dan Williams <dan.j.williams@xxxxxxxxx>
>> | Sent: Monday, September 25, 2017 12:31 PM
>> | ...
>> | IIUC it looks like this has been broken ever since commit e1605495c716
>> | "intel-iommu: Introduce domain_sg_mapping() to speed up
>> | intel_map_sg()". I.e. it looks like the calculation for pte_val should
>> | be:
>> |
>> |     pteval = (page_to_phys(sg_page(sg)) + sg->offset) | prot;
>>
>> Hhmmm, shouldn't that be:
>>
>>     pteval = (page_to_phys(sg_page(sg)) + (sg->offset>>PAGE_SHIFT)) | prot;
> Yes, I think you're right. We do want to mask off the page-unaligned
> portion of sg->offset.
Tried changing above line in "__domain_mapping" but didn't help.