iommu/vt-d: Add debugfs support to show context internals

Export Intel IOMMU DMA remapping internal states, such as root and
context table entries in debugfs.

Example of such dump in Kabylake:
/sys/kernel/debug/iommu/intel/dmar_translation_struct

IOMMU dmar0: Root Table Address:45699c000
Root Table Entries:
 Bus: 0 H: 0 L: 45699f001
 Context Table Entries for Bus: 0
  Entry B:D.F   High    Low
  16    00:02.0 102     45699e005

IOMMU dmar1: Root Table Address:45699d000
Root Table Entries:
 Bus: 0 H: 0 L: 45644f001
 Context Table Entries for Bus: 0
  Entry B:D.F   High    Low
  160   00:14.0 102     45644e001
  184   00:17.0 302     456310001
  248   00:1f.0 202     4564bf001

Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Co-Developed-by: Gayatri Kammela <gayatri.kammela@intel.com>
Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
index 2becbd7..7fabf9b 100644 (file)
--- a/drivers/iommu/intel-iommu-debugfs.c
+++ b/drivers/iommu/intel-iommu-debugfs.c
@@ -131,6 +131,69 @@ out:
 }
 DEFINE_SHOW_ATTRIBUTE(iommu_regset);
 
+static void ctx_tbl_entry_show(struct seq_file *m, struct intel_iommu *iommu,
+                              int bus)
+{
+       struct context_entry *context;
+       int devfn;
+
+       seq_printf(m, " Context Table Entries for Bus: %d\n", bus);
+       seq_puts(m, "  Entry\tB:D.F\tHigh\tLow\n");
+
+       for (devfn = 0; devfn < 256; devfn++) {
+               context = iommu_context_addr(iommu, bus, devfn, 0);
+               if (!context)
+                       return;
+
+               if (!context_present(context))
+                       continue;
+
+               seq_printf(m, "  %-5d\t%02x:%02x.%x\t%-6llx\t%llx\n", devfn,
+                          bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+                          context[0].hi, context[0].lo);
+       }
+}
+
+static void root_tbl_entry_show(struct seq_file *m, struct intel_iommu *iommu)
+{
+       unsigned long flags;
+       int bus;
+
+       spin_lock_irqsave(&iommu->lock, flags);
+       seq_printf(m, "IOMMU %s: Root Table Address:%llx\n", iommu->name,
+                  (u64)virt_to_phys(iommu->root_entry));
+       seq_puts(m, "Root Table Entries:\n");
+
+       for (bus = 0; bus < 256; bus++) {
+               if (!(iommu->root_entry[bus].lo & 1))
+                       continue;
+
+               seq_printf(m, " Bus: %d H: %llx L: %llx\n", bus,
+                          iommu->root_entry[bus].hi,
+                          iommu->root_entry[bus].lo);
+
+               ctx_tbl_entry_show(m, iommu, bus);
+               seq_putc(m, '\n');
+       }
+       spin_unlock_irqrestore(&iommu->lock, flags);
+}
+
+static int dmar_translation_struct_show(struct seq_file *m, void *unused)
+{
+       struct dmar_drhd_unit *drhd;
+       struct intel_iommu *iommu;
+
+       rcu_read_lock();
+       for_each_active_iommu(iommu, drhd) {
+               root_tbl_entry_show(m, iommu);
+               seq_putc(m, '\n');
+       }
+       rcu_read_unlock();
+
+       return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(dmar_translation_struct);
+
 #ifdef CONFIG_IRQ_REMAP
 static void ir_tbl_remap_entry_show(struct seq_file *m,
                                    struct intel_iommu *iommu)
@@ -242,6 +305,8 @@ void __init intel_iommu_debugfs_init(void)
 
        debugfs_create_file("iommu_regset", 0444, intel_iommu_debug, NULL,
                            &iommu_regset_fops);
+       debugfs_create_file("dmar_translation_struct", 0444, intel_iommu_debug,
+                           NULL, &dmar_translation_struct_fops);
 #ifdef CONFIG_IRQ_REMAP
        debugfs_create_file("ir_translation_struct", 0444, intel_iommu_debug,
                            NULL, &ir_translation_struct_fops);