On Tue, Jul 14, 2026 at 09:06:50PM +0800, Zhanpeng Zhang wrote: > This RFC extends RISC-V CBQRI/resctrl support to external requesters > behind a RISC-V IOMMU. [..] > Open questions for this RFC: > > * whether a common resctrl "devices" file is the right ABI for > associating external requesters with a resource group;
I think a separate file is the right approach to avoid confusing iommu groups with pids. I should note that James Morse had an ARM MPAM "extras" tree [1] which carried an iommu_group assignment interface, using the same iommu_group:<id> format, but writing it to the tasks file. However, Ben Horgan clarified back in March [2] in a reply to Qinxin Xia that it is no longer maintained. Ben also wrote that the interface would likely change upstream. I've added Ben Horgan and Qinxin Xia to the CC list so hopefully they can chime in. I plan to review the patches in this series further but I didn't want to delay any further in pointing out the above. Thanks, Drew [1] https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot%2Bextras/v6.18-rc1 [2] https://lore.kernel.org/lkml/[email protected]/
