Messages in this thread | | | Date | Tue, 11 Jul 2023 09:40:37 +0800 | Subject | Re: [PATCH 0/5] iommu/vt-d: debugfs: Enhancements to IOMMU debugfs | From | "Liu, Jingqi" <> |
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On 7/4/2023 3:54 PM, Tian, Kevin wrote: >> From: Liu, Jingqi <jingqi.liu@intel.com> >> Sent: Monday, July 3, 2023 10:37 PM >> >> On 7/3/2023 3:15 PM, Tian, Kevin wrote: >>>> From: Liu, Jingqi <jingqi.liu@intel.com> >>>> Sent: Sunday, June 25, 2023 11:05 PM >>>> >>>> The original debugfs only dumps all IOMMU page tables without pasid >>>> supported. It traverses all devices on the pci bus, then dumps all page >>>> tables based on device domains. This traversal is from software >>>> perspective. >>>> >>>> This series dumps page tables by traversing root tables, context tables, >>>> pasid directories and pasid tables from hardware perspective. By >>>> specifying source identifier and PASID, it supports dumping specified >>>> page table or all page tables in legacy mode or scalable mode. >>>> >>>> For a device that only supports legacy mode, specify the source >>>> identifier, and search the root table and context table to dump its >>>> page table. It does not support to specify PASID. >>>> >>>> For a device that supports scalable mode, specify a >>>> {source identifier, PASID} pair and search the root table, context table >>>> and pasid table to dump its page table. If the pasid is not specified, >>>> it is set to RID_PASID. >>>> >>>> Switch to dump all page tables by specifying "auto". >>>> >>>> Examples are as follows: >>>> 1) Dump the page table of device "00:1f.0" that only supports legacy >>>> mode. >>>> >>>> $ sudo echo 00:1f.0 > >>>> /sys/kernel/debug/iommu/intel/domain_translation_struct >>>> $ sudo cat /sys/kernel/debug/iommu/intel/domain_translation_struct >>>> Device 0000:00:1f.0 @0x105407000 >>>> IOVA_PFN PML5E PML4E >>>> 0x0000000000000 | 0x0000000000000000 0x0000000105408003 >>>> 0x0000000000001 | 0x0000000000000000 0x0000000105408003 >>>> 0x0000000000002 | 0x0000000000000000 0x0000000105408003 >>>> 0x0000000000003 | 0x0000000000000000 0x0000000105408003 >>>> >>>> PDPE PDE PTE >>>> 0x0000000105409003 0x000000010540a003 0x0000000000000003 >>>> 0x0000000105409003 0x000000010540a003 0x0000000000001003 >>>> 0x0000000105409003 0x000000010540a003 0x0000000000002003 >>>> 0x0000000105409003 0x000000010540a003 0x0000000000003003 >>>> >>>> [...] >>>> >>>> 2) Dump the page table of device "00:0a.0" with pasid "2". >>>> >>>> $ sudo echo 00:0a.0,2 > >>>> /sys/kernel/debug/iommu/intel/domain_translation_struct >>>> $ sudo cat /sys/kernel/debug/iommu/intel/domain_translation_struct >>> What about creating a directory layout per {dev, pasid} so the user can >>> easily figure out and dump? >>> >>> e.g. >>> >>> /sys/kernel/debug/iommu/intel/00:0a.0/0/domain_translation_struct >>> /sys/kernel/debug/iommu/intel/00:0a.0/2/domain_translation_struct >> Thanks. >> >> Do you mean create a directory for each device, whether it supports >> PASID or not ? > every device has PASID#0 valid, i.e. RID2PASID. Sorry for the late response. Got it. Thanks. >> Seems the PASID can be assigned at runtime. >> So it needs to support creating debugfs file at runtime in IOMMU driver. >> Looks like this requires modifying IOMMU driver. >> > Isn't this patch trying to modify the driver? I just tried not to modify the driver except debugfs. I'll try this implementation.
Thanks, Jingqi
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