[PATCH v3 2/4] iommu/vt-d: debugfs: Add support to show inv queue internals

Lu Baolu
2020-04-22T08:09:31Z

Export invalidation queue internals of each iommu device through the
debugfs.

Example of such dump on a Skylake machine:

$ sudo cat /sys/kernel/debug/iommu/intel/invalidation_queue
Invalidation queue on IOMMU: dmar1
Base: 0x1672c9000 Head: 80 Tail: 80
Index qw0 qw1 status
0 0000000000000004 0000000000000000 0000000000000000
1 0000000200000025 00000001672be804 0000000000000000
2 0000000000000011 0000000000000000 0000000000000000
3 0000000200000025 00000001672be80c 0000000000000000
4 00000000000000d2 0000000000000000 0000000000000000
5 0000000200000025 00000001672be814 0000000000000000
6 0000000000000014 0000000000000000 0000000000000000
7 0000000200000025 00000001672be81c 0000000000000000
8 0000000000000014 0000000000000000 0000000000000000
9 0000000200000025 00000001672be824 0000000000000000

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu-debugfs.c | 62 +++++++++++++++++++++++++++++
1 file changed, 62 insertions(+)

diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
index 3eb1fe240fb0..e3089865b8f3 100644
--- a/drivers/iommu/intel-iommu-debugfs.c
+++ b/drivers/iommu/intel-iommu-debugfs.c
@@ -372,6 +372,66 @@ static int domain_translation_struct_show(struct seq_file *m, void *unused)
}
DEFINE_SHOW_ATTRIBUTE(domain_translation_struct);

+static void invalidation_queue_entry_show(struct seq_file *m,
+ struct intel_iommu *iommu)
+{
+ int index, shift = qi_shift(iommu);
+ struct qi_desc *desc;
+ int offset;
+
+ if (ecap_smts(iommu->ecap))
+ seq_puts(m, "Index\t\tqw0\t\t\tqw1\t\t\tqw2\t\t\tqw3\t\t\tstatus\n");
+ else
+ seq_puts(m, "Index\t\tqw0\t\t\tqw1\t\t\tstatus\n");
+
+ for (index = 0; index < QI_LENGTH; index++) {
+ offset = index << shift;
+ desc = iommu->qi->desc + offset;
+ if (ecap_smts(iommu->ecap))
+ seq_printf(m, "%5d\t%016llx\t%016llx\t%016llx\t%016llx\t%016x\n",
+ index, desc->qw0, desc->qw1,
+ desc->qw2, desc->qw3,
+ iommu->qi->desc_status[index]);
+ else
+ seq_printf(m, "%5d\t%016llx\t%016llx\t%016x\n",
+ index, desc->qw0, desc->qw1,
+ iommu->qi->desc_status[index]);
+ }
+}
+
+static int invalidation_queue_show(struct seq_file *m, void *unused)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ unsigned long flags;
+ struct q_inval *qi;
+ int shift;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ qi = iommu->qi;
+ shift = qi_shift(iommu);
+
+ if (!qi || !ecap_qis(iommu->ecap))
+ continue;
+
+ seq_printf(m, "Invalidation queue on IOMMU: %s\n", iommu->name);
+
+ raw_spin_lock_irqsave(&qi->q_lock, flags);
+ seq_printf(m, " Base: 0x%llx\tHead: %lld\tTail: %lld\n",
+ virt_to_phys(qi->desc),
+ dmar_readq(iommu->reg + DMAR_IQH_REG) >> shift,
+ dmar_readq(iommu->reg + DMAR_IQT_REG) >> shift);
+ invalidation_queue_entry_show(m, iommu);
+ raw_spin_unlock_irqrestore(&qi->q_lock, flags);
+ seq_putc(m, '\n');
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(invalidation_queue);
+
#ifdef CONFIG_IRQ_REMAP
static void ir_tbl_remap_entry_show(struct seq_file *m,
struct intel_iommu *iommu)
@@ -490,6 +550,8 @@ void __init intel_iommu_debugfs_init(void)
debugfs_create_file("domain_translation_struct", 0444,
intel_iommu_debug, NULL,
&domain_translation_struct_fops);
+ debugfs_create_file("invalidation_queue", 0444, intel_iommu_debug,
+ NULL, &invalidation_queue_fops);
#ifdef CONFIG_IRQ_REMAP
debugfs_create_file("ir_translation_struct", 0444, intel_iommu_debug,
NULL, &ir_translation_struct_fops);
--
2.17.1