On Fri, Sep 25, 2020 at 12:06:17PM -0700, Ashok Raj wrote: > Presently, the default domain of an iommu group is allocated during boot time > and it cannot be changed later. So, the device would typically be either in > identity (pass_through) mode or the device would be in DMA mode as long as the > system is up and running. There is no way to change the default domain type > dynamically i.e. after booting, a device cannot switch between identity mode > and > DMA mode. > > Assume a use case wherein the privileged user would want to use the device in > pass-through mode when the device is used for host so that it would be high > performing. Presently, this is not supported. Hence add support to change the > default domain of an iommu group dynamically. > > Support this by writing to a sysfs file, namely > "/sys/kernel/iommu_groups/<grp_id>/type". > > Testing: > -------- > Tested by dynamically changing storage device (nvme) from > 1. identity mode to DMA and making sure file transfer works > 2. DMA mode to identity mode and making sure file transfer works > Tested only for intel_iommu/vt-d. Would appreciate if someone could test on > AMD > and ARM based machines. > > Based on iommu maintainer's 'next' branch.
Modulo my minor comments, I think this looks good for 5.11 if you can please send a version 9. Robin -- please can you give it the once-over too? I think root can break things quite badly with this interface, but root can do that in other ways anyway... Will _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
