[Public] > -----Original Message----- > From: Dave Hansen <dave.hansen@xxxxxxxxx> > Sent: Tuesday, March 29, 2022 11:25 AM > To: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; linux- > doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; corbet@xxxxxxx; > hpa@xxxxxxxxx; x86@xxxxxxxxxx; dave.hansen@xxxxxxxxxxxxxxx; > bp@xxxxxxxxx; mingo@xxxxxxxxxx; tglx@xxxxxxxxxxxxx; joro@xxxxxxxxxx; > Suthikulpanit, Suravee <Suravee.Suthikulpanit@xxxxxxx>; will@xxxxxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; robin.murphy@xxxxxxx; Hegde, Vasant > <Vasant.Hegde@xxxxxxx> > Subject: Re: [PATCH V3 1/2] Documentation: x86: Add documentation for > AMD IOMMU > > On 3/28/22 10:28, Alex Deucher wrote: > > +How is IOVA generated? > > +---------------------- > > + > > +Well behaved drivers call dma_map_*() calls before sending command to > > +device that needs to perform DMA. Once DMA is completed and mapping > > +is no longer required, driver performs dma_unmap_*() calls to unmap the > region. > > + > > +Fault reporting > > +--------------- > > + > > +When errors are reported, the IOMMU signals via an interrupt. The > > +fault reason and device that caused it is printed on the console. > > Just scanning this, it looks *awfully* generic. Is anything in here AMD- > specific? Should this be in an AMD-specific file? There is some information about the ACPI tables used to enumerate the IOMMUs and a link to the AMD IOMMU programming documentation. Would you prefer I just create a combined x86 IOMMU document? Alex
