Messages in this thread | | | From | "Deucher, Alexander" <> | Subject | RE: [PATCH V3 1/2] Documentation: x86: Add documentation for AMD IOMMU | Date | Wed, 30 Mar 2022 14:01:00 +0000 |
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[Public]
> -----Original Message----- > From: Dave Hansen <dave.hansen@intel.com> > Sent: Tuesday, March 29, 2022 11:25 AM > To: Deucher, Alexander <Alexander.Deucher@amd.com>; linux- > doc@vger.kernel.org; linux-kernel@vger.kernel.org; corbet@lwn.net; > hpa@zytor.com; x86@kernel.org; dave.hansen@linux.intel.com; > bp@alien8.de; mingo@redhat.com; tglx@linutronix.de; joro@8bytes.org; > Suthikulpanit, Suravee <Suravee.Suthikulpanit@amd.com>; will@kernel.org; > iommu@lists.linux-foundation.org; robin.murphy@arm.com; Hegde, Vasant > <Vasant.Hegde@amd.com> > 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
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