> -----Original Message----- > From: Joerg Roedel [mailto:joerg.roe...@amd.com] > Sent: Friday, January 27, 2012 12:21 AM > To: Wood Scott-B07421 > Cc: Sethi Varun-B16395; iommu@lists.linux-foundation.org; Ohad Ben-Cohen; > Tony Lindgren; Hiroshi DOYU; linux-ker...@vger.kernel.org; Laurent > Pinchart; Wood Scott-B07421; David Brown; David Woodhouse > Subject: Re: [PATCH 2/5] iommu/amd: Implement DOMAIN_ATTR_GEOMETRY > attribute > > On Thu, Jan 26, 2012 at 12:42:10PM -0600, Scott Wood wrote: > > On 01/26/2012 12:31 PM, Joerg Roedel wrote: > > > The force_aperture flag indicated whether DMA is only allowed > > > between aperture_start and apertuer_end or if DMA is allowed outside > > > of this range too (unmapped in this case). > > > > > > The AMD GART for example would set this flag to false because it > > > does not enforce DMA to be in the aperture-range. > > > > Why is this not an AMD GART specific attribute? Is there any feature > > reporting mechanism by which a user would know if that flag is > supported? > > Because this is a flag that makes sense for all IOMMU. Every IOMMU either > allows DMA outside its aperture or it doesn't. > > Another reason why it must be in the generic struct is the intended > generic dma-ops layer on-top. This code can decide on this flag wheter a > address needs to be remapped at all.
Can you please explain how would IOMMU remapping be used, based on the force_aperture flag. -Varun _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
