On 4/24/19 5:04 PM, Eric Pilmore wrote: > On Tue, Apr 23, 2019 at 4:00 AM Sanjay R Mehta <sanmehta@xxxxxxx> wrote: >> >> >>> AMD-Vi: Event logged [IO_PAGE_FAULT device=23:01.2 domain=0x0000 >>> address=0x00000000fde1c18c flags=0x0070] >> >> the address in the above log looks to be physical address of memory window. Am I Right? >> >> If yes then, the first parameter of dma_alloc_coherent() to be passed as below, >> >> dma_alloc_coherent(&ntb->pdev->dev, ...)instead of dma_alloc_coherent(&ntb->dev, ...). >> >> Hope this should solve your problem. > > Hi Sanjay, > > Thanks the for the response. We are using the correct device for the > dma_alloc_coherent(). Upon further investigation what we are finding > is that apparently the AMD IOMMU support can only manage one alias, as > opposed to Intel IOMMU support which can support multiple. Not clear > at this time if it's a software limitation in the AMD IOMMU kernel > support or an imposed limitation of the hardware. Still investigating. Please define 'alias'? The IO_PAGE_FAULT error is described on page 142 of the AMD IOMMU spec, document #48882. Easily found via a search. The flags value of 0x0070 translates to PE, RW, PR. The page was present, the transaction was a write, and the peripheral didn't have permission. That implies that mapping hadn't been done. Not being sure how that device presents, or what you're doing with IVHD info, I can't comment further. I can say that the AMD IOMMU provides for a single exclusion range, but as many unity ranges as you wish. HTH grh
