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Subject[PATCH v8 6/6] iommu/vt-d: Add debugfs support to show context internals
Date
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>
---

v8: Remove extended context support since it is deprecated in the new spec
Use iommu lock to protect context table access
Simplify and split the patches differently

v7: Split patch 1/5 and 2/5 differently
Update commit message and copyright year
Fix typo in a comment
Simplify code

v6: Change the order of includes to an alphabetical order
Change seq_printf formatting

v5: Change to a SPDX license tag
Fix seq_printf formatting

v4: Remove the unused function parameter
Fix checkpatch.pl warnings
Remove error reporting for debugfs_create_file function
Fix unnecessary reprogramming of the context entries
Simplify and merge the show context and extended context patch into one
Remove redundant IOMMU null check under for_each_active_iommu

v3: Add a macro for seq file operations
Change the intel_iommu_ctx file name to dmar_translation_struct

v2: No change

drivers/iommu/intel-iommu-debugfs.c | 65 +++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
index 2becbd78620f..7fabf9b1c2dc 100644
--- a/drivers/iommu/intel-iommu-debugfs.c
+++ b/drivers/iommu/intel-iommu-debugfs.c
@@ -131,6 +131,69 @@ static int iommu_regset_show(struct seq_file *m, void *unused)
}
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);
--
2.18.0
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