From 8e48ff29e7d5d46598cbc697a41e17196a8e100f Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] iommu/vt-d: Fix checks and print in pgtable_walk() BugLink: https://bugs.launchpad.net/bugs/2101915 [ Upstream commit f1645676f25d2c846798f0233c3a953efd62aafb ] There are some issues in pgtable_walk(): 1. Super page is dumped as non-present page 2. dma_pte_superpage() should not check against leaf page table entries 3. Pointer pte is never NULL so checking it is meaningless 4. When an entry is not present, it still makes sense to dump the entry content. Fix 1,2 by checking dma_pte_superpage()'s returned value after level check. Fix 3 by removing pte check. Fix 4 by checking present bit after printing. By this chance, change to print "page table not present" instead of "PTE not present" to be clearer. Fixes: 914ff7719e8a ("iommu/vt-d: Dump DMAR translation structure when DMA fault occurs") Signed-off-by: Zhenzhong Duan Link: https://lore.kernel.org/r/20241024092146.715063-3-zhenzhong.duan@intel.com Signed-off-by: Lu Baolu Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/iommu/intel/iommu.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 8b06192667ba..cfaa45df8ece 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -754,14 +754,15 @@ static void pgtable_walk(struct intel_iommu *iommu, unsigned long pfn, while (1) { offset = pfn_level_offset(pfn, level); pte = &parent[offset]; - if (!pte || (dma_pte_superpage(pte) || !dma_pte_present(pte))) { - pr_info("PTE not present at level %d\n", level); - break; - } pr_info("pte level: %d, pte value: 0x%016llx\n", level, pte->val); - if (level == 1) + if (!dma_pte_present(pte)) { + pr_info("page table not present at level %d\n", level - 1); + break; + } + + if (level == 1 || dma_pte_superpage(pte)) break; parent = phys_to_virt(dma_pte_addr(pte));