Messages in this thread | | | Date | Fri, 10 Mar 2023 11:33:00 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v1 01/14] iommu: Add iommu_get_unmanaged_domain helper |
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On Fri, Mar 10, 2023 at 11:14:59AM +0100, Eric Auger wrote: > Hi Nicolin, > > On 3/9/23 11:53, Nicolin Chen wrote: > > The nature of ITS virtualization on ARM is done via hypercalls, so kernel > > handles all IOVA mappings for the MSI doorbell in iommu_dma_prepare_msi() > > and iommu_dma_compose_msi_msg(). The current virtualization solution with > > a 2-stage nested translation setup is to do 1:1 IOVA mappings at stage-1 > Note that if we still intend to use that trick there is a known issue at > kernel side that needs to be fixed. > > ARM DEN 0049E.b IORT specification mandates that when > RMRs are present, the OS must preserve PCIe configuration > performed by the boot FW.
This limitation doesn't seem necessary for this MSI stuff?
What is it for?
Jason
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