[PATCH v8 4/6] iommu/vt-d: Add debugfs support to show register contents

From: Sohil Mehta
Date: Tue Sep 11 2018 - 20:10:31 EST

From: Gayatri Kammela <gayatri.kammela@xxxxxxxxx>

Add Intel IOMMU debugfs extension to dump all the register contents for
each IOMMU device.

Example:
root@OTC-KBLH-01:~# cat /sys/kernel/debug/iommu/intel/iommu_regset
IOMMU: dmar0 Register Base Address: fed90000
Name Offset Contents
VER 0x00 0x0000000000000010
CAP 0x08 0x01c0000c40660462
ECAP 0x10 0x0000000000f0101a
GCMD 0x18 0x0000000000000000
GSTS 0x1c 0x00000000c7000000
RTADDR 0x20 0x00000004071d3800
CCMD 0x28 0x0800000000000000
FSTS 0x34 0x0000000000000000
FECTL 0x38 0x0000000000000000
FEDATA 0x3c 0xfee0100400004021

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

v8: Add MTRR and Virtual command register support
Use the iommu register lock to protect register access

v7: Use macro for register set definitions
Fix compiler warning for readq with 32bit architecture
Remove leading '\n'

v6: No change

v5: No change

v4: Fix checkpatch.pl warnings
Remove error reporting for debugfs_create_file function
Remove redundant IOMMU null check under for_each_active_iommu

v3: Use a macro for seq file operations
Change the intel_iommu_regset file name to iommu_regset
Add information for MTRR registers

v2: Fix seq_printf formatting

drivers/iommu/intel-iommu-debugfs.c | 123 +++++++++++++++++++++++++++-
1 file changed, 122 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
index 33e0a6c12d92..57af2f774312 100644
--- a/drivers/iommu/intel-iommu-debugfs.c
+++ b/drivers/iommu/intel-iommu-debugfs.c
@@ -14,7 +14,128 @@

#include <asm/irq_remapping.h>

+struct iommu_regset {
+ int offset;
+ const char *regs;
+};
+
+#define IOMMU_REGSET_ENTRY(_reg_) \
+ { DMAR_##_reg_##_REG, __stringify(_reg_) }
+static const struct iommu_regset iommu_regs[] = {
+ IOMMU_REGSET_ENTRY(VER),
+ IOMMU_REGSET_ENTRY(CAP),
+ IOMMU_REGSET_ENTRY(ECAP),
+ IOMMU_REGSET_ENTRY(GCMD),
+ IOMMU_REGSET_ENTRY(GSTS),
+ IOMMU_REGSET_ENTRY(RTADDR),
+ IOMMU_REGSET_ENTRY(CCMD),
+ IOMMU_REGSET_ENTRY(FSTS),
+ IOMMU_REGSET_ENTRY(FECTL),
+ IOMMU_REGSET_ENTRY(FEDATA),
+ IOMMU_REGSET_ENTRY(FEADDR),
+ IOMMU_REGSET_ENTRY(FEUADDR),
+ IOMMU_REGSET_ENTRY(AFLOG),
+ IOMMU_REGSET_ENTRY(PMEN),
+ IOMMU_REGSET_ENTRY(PLMBASE),
+ IOMMU_REGSET_ENTRY(PLMLIMIT),
+ IOMMU_REGSET_ENTRY(PHMBASE),
+ IOMMU_REGSET_ENTRY(PHMLIMIT),
+ IOMMU_REGSET_ENTRY(IQH),
+ IOMMU_REGSET_ENTRY(IQT),
+ IOMMU_REGSET_ENTRY(IQA),
+ IOMMU_REGSET_ENTRY(ICS),
+ IOMMU_REGSET_ENTRY(IRTA),
+ IOMMU_REGSET_ENTRY(PQH),
+ IOMMU_REGSET_ENTRY(PQT),
+ IOMMU_REGSET_ENTRY(PQA),
+ IOMMU_REGSET_ENTRY(PRS),
+ IOMMU_REGSET_ENTRY(PECTL),
+ IOMMU_REGSET_ENTRY(PEDATA),
+ IOMMU_REGSET_ENTRY(PEADDR),
+ IOMMU_REGSET_ENTRY(PEUADDR),
+ IOMMU_REGSET_ENTRY(MTRRCAP),
+ IOMMU_REGSET_ENTRY(MTRRDEF),
+ IOMMU_REGSET_ENTRY(MTRR_FIX64K_00000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX16K_80000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX16K_A0000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_C0000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_C8000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_D0000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_D8000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_E0000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_E8000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_F0000),
+ IOMMU_REGSET_ENTRY(MTRR_FIX4K_F8000),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE0),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK0),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE1),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK1),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE2),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK2),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE3),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK3),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE4),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK4),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE5),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK5),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE6),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK6),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE7),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK7),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE8),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK8),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSBASE9),
+ IOMMU_REGSET_ENTRY(MTRR_PHYSMASK9),
+ IOMMU_REGSET_ENTRY(VCCAP),
+ IOMMU_REGSET_ENTRY(VCMD),
+ IOMMU_REGSET_ENTRY(VCRSP),
+};
+
+static int iommu_regset_show(struct seq_file *m, void *unused)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ unsigned long flag;
+ int i, ret = 0;
+ u64 value;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (!drhd->reg_base_addr) {
+ seq_puts(m, "IOMMU: Invalid base address\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ seq_printf(m, "IOMMU: %s Register Base Address: %llx\n",
+ iommu->name, drhd->reg_base_addr);
+ seq_puts(m, "Name\t\t\tOffset\t\tContents\n");
+ /*
+ * Publish the contents of the 64-bit hardware registers
+ * by adding the offset to the pointer (virtual address).
+ */
+ raw_spin_lock_irqsave(&iommu->register_lock, flag);
+ for (i = 0 ; i < ARRAY_SIZE(iommu_regs); i++) {
+ value = dmar_readq(iommu->reg + iommu_regs[i].offset);
+ seq_printf(m, "%-16s\t0x%02x\t\t0x%016llx\n",
+ iommu_regs[i].regs, iommu_regs[i].offset,
+ value);
+ }
+ raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
+ seq_putc(m, '\n');
+ }
+out:
+ rcu_read_unlock();
+
+ return ret;
+}
+DEFINE_SHOW_ATTRIBUTE(iommu_regset);
+
void __init intel_iommu_debugfs_init(void)
{
- debugfs_create_dir("intel", iommu_debugfs_dir);
+ struct dentry *intel_iommu_debug = debugfs_create_dir("intel",
+ iommu_debugfs_dir);
+
+ debugfs_create_file("iommu_regset", 0444, intel_iommu_debug, NULL,
+ &iommu_regset_fops);
}
--
2.18.0