kernel/linux.git/drivers/iommu/intel/debugfs.c, branch v6.12.80

iommu/vt-d: Replace snprintf with scnprintf in dmar_latency_snapshot()

2025-11-13T20:34:27+00:00

[ Upstream commit 75c02a037609f34db17e91be195cedb33b61bae0 ] snprintf() returns the number of bytes that would have been written, not the number actually written. Using this for offset tracking can cause buffer overruns if truncation occurs. Replace snprintf() with scnprintf() to ensure the offset stays within bounds. Since scnprintf() never returns a negative value, and zero is not possible in this context because 'bytes' starts at 0 and 'size - bytes' is DEBUG_BUFFER_SIZE in the first call, which is large enough to hold the string literals used, the return value is always positive. An integer overflow is also completely out of reach here due to the small and fixed buffer size. The error check in latency_show_one() is therefore unnecessary. Remove it and make dmar_latency_snapshot() return void. Signed-off-by: Seyediman Seyedarab Link: https://lore.kernel.org/r/20250731225048.131364-1-ImanDevel@gmail.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin

iommu/vt-d: debugfs: Fix legacy mode page table dump logic

2025-10-15T10:00:13+00:00

[ Upstream commit fbe6070c73badca726e4ff7877320e6c62339917 ] In legacy mode, SSPTPTR is ignored if TT is not 00b or 01b. SSPTPTR maybe uninitialized or zero in that case and may cause oops like: Oops: general protection fault, probably for non-canonical address 0xf00087d3f000f000: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 786 Comm: cat Not tainted 6.16.0 #191 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-5.fc42 04/01/2014 RIP: 0010:pgtable_walk_level+0x98/0x150 RSP: 0018:ffffc90000f279c0 EFLAGS: 00010206 RAX: 0000000040000000 RBX: ffffc90000f27ab0 RCX: 000000000000001e RDX: 0000000000000003 RSI: f00087d3f000f000 RDI: f00087d3f0010000 RBP: ffffc90000f27a00 R08: ffffc90000f27a98 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000000 R12: f00087d3f000f000 R13: 0000000000000000 R14: 0000000040000000 R15: ffffc90000f27a98 FS: 0000764566dcb740(0000) GS:ffff8881f812c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000764566d44000 CR3: 0000000109d81003 CR4: 0000000000772ef0 PKRU: 55555554 Call Trace: pgtable_walk_level+0x88/0x150 domain_translation_struct_show.isra.0+0x2d9/0x300 dev_domain_translation_struct_show+0x20/0x40 seq_read_iter+0x12d/0x490 ... Avoid walking the page table if TT is not 00b or 01b. Fixes: 2b437e804566 ("iommu/vt-d: debugfs: Support dumping a specified page table") Signed-off-by: Vineeth Pillai (Google) Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20250814163153.634680-1-vineeth@bitbyteword.org Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin

iommu/vt-d: Remove debugfs use of private data field

2024-04-26T09:57:38+00:00

Since the page fault report and response have been tracked by ftrace, the users can easily calculate the time used for a page fault handling. There's no need to expose the similar functionality in debugfs. Hence, remove the corresponding operations in debugfs. Signed-off-by: Jingqi Liu Link: https://lore.kernel.org/r/20240308103811.76744-2-Jingqi.liu@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel

iommu/vt-d: Remove unused vcmd interfaces

2023-12-19T13:32:28+00:00

Commit 99b5726b4423 ("iommu: Remove ioasid infrastructure") has removed ioasid allocation interfaces from the iommu subsystem. As a result, these vcmd interfaces have become obsolete. Remove them to avoid dead code. Signed-off-by: Lu Baolu Link: https://lore.kernel.org/r/20231116015048.29675-4-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel

iommu/vt-d: debugfs: Support dumping a specified page table

2023-10-16T07:34:52+00:00

The original debugfs only dumps all page tables without pasid. With pasid supported, the page table with pasid also needs to be dumped. This patch supports dumping a specified page table in legacy mode or scalable mode with or without a specified pasid. For legacy mode, according to bus number and DEVFN, traverse the root table and context table to get the pointer of page table in the context table entry, then dump the specified page table. For scalable mode, according to bus number, DEVFN and pasid, traverse the root table, context table, pasid directory and pasid table to get the pointer of page table in the pasid table entry, then dump the specified page table.. Examples are as follows: 1) Dump the page table of device "0000:00:1f.0" that only supports legacy mode. $ sudo cat /sys/kernel/debug/iommu/intel/0000:00:1f.0/domain_translation_struct 2) Dump the page table of device "0000:00:0a.0" with PASID "1" that supports scalable mode. $ sudo cat /sys/kernel/debug/iommu/intel/0000:00:0a.0/1/domain_translation_struct Suggested-by: Kevin Tian Signed-off-by: Jingqi Liu Link: https://lore.kernel.org/r/20231013135811.73953-4-Jingqi.liu@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel

iommu/vt-d: debugfs: Create/remove debugfs file per {device, pasid}

2023-10-16T07:34:51+00:00

Add a debugfs directory per pair of {device, pasid} if the mappings of its page table are created and destroyed by the iommu_map/unmap() interfaces. i.e. /sys/kernel/debug/iommu/intel//. Create a debugfs file in the directory for users to dump the page table corresponding to {device, pasid}. e.g. /sys/kernel/debug/iommu/intel/0000:00:02.0/1/domain_translation_struct. For the default domain without pasid, it creates a debugfs file in the debugfs device directory for users to dump its page table. e.g. /sys/kernel/debug/iommu/intel/0000:00:02.0/domain_translation_struct. When setting a domain to a PASID of device, create a debugfs file in the pasid debugfs directory for users to dump the page table of the specified pasid. Remove the debugfs device directory of the device when releasing a device. e.g. /sys/kernel/debug/iommu/intel/0000:00:01.0 Signed-off-by: Jingqi Liu Link: https://lore.kernel.org/r/20231013135811.73953-3-Jingqi.liu@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel

iommu/vt-d: debugfs: Dump entry pointing to huge page

2023-10-16T07:34:51+00:00

For the page table entry pointing to a huge page, the data below the level of the huge page is meaningless and does not need to be dumped. Signed-off-by: Jingqi Liu Link: https://lore.kernel.org/r/20231013135811.73953-2-Jingqi.liu@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel

iommu/vt-d: Replace spin_lock_irqsave() with spin_lock()

2022-07-15T08:21:36+00:00

The iommu->lock is used to protect changes in root/context/pasid tables and domain ID allocation. There's no use case to change these resources in any interrupt context. Therefore, it is unnecessary to disable the interrupts when the spinlock is held. The same thing happens on the device_domain_lock side, which protects the device domain attachment information. This replaces spin_lock/unlock_irqsave/irqrestore() calls with the normal spin_lock/unlock(). Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20220706025524.2904370-6-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel

iommu/vt-d: debugfs: Remove device_domain_lock usage

2022-07-15T08:21:33+00:00

The domain_translation_struct debugfs node is used to dump the DMAR page tables for the PCI devices. It potentially races with setting domains to devices. The existing code uses the global spinlock device_domain_lock to avoid the races. This removes the use of device_domain_lock outside of iommu.c by replacing it with the group mutex lock. Using the group mutex lock is cleaner and more compatible to following cleanups. Signed-off-by: Lu Baolu Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/20220706025524.2904370-2-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel

iommu/vt-d: Move include/linux/intel-iommu.h under iommu

2022-07-15T08:21:31+00:00

This header file is private to the Intel IOMMU driver. Move it to the driver folder. Signed-off-by: Lu Baolu Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Steve Wahl Link: https://lore.kernel.org/r/20220514014322.2927339-8-baolu.lu@linux.intel.com Signed-off-by: Joerg Roedel