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Subject[PATCH 4/6] iommu/vt-d: Add debugfs extension to show register contents
Date
From: Gayatri Kammela <gayatri.kammela@intel.com>

Debugfs extension to dump all the register contents for each IOMMU
device to the user space via debugfs.

example:
root@OTC-KBLH-01:~# cat /sys/kernel/debug/intel_iommu/intel_iommu_regset

DMAR: dmar1: reg_base_addr fed90000
Name Offset Contents
VER 0x00 0x0000000000000010
CAP 0x08 0x01c0000c40660462
ECAP 0x10 0x0000019e2ff0505e
GCMD 0x18 0x0000000000000000
GSTS 0x1c 0x00000000c7000000
RTADDR 0x20 0x00000004558d6800
CCMD 0x28 0x0800000000000000
FSTS 0x34 0x0000000000000000
FECTL 0x38 0x0000000000000000
FEDATA 0x3c 0xfee0100c00004141

Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com>
---
drivers/iommu/intel-iommu-debug.c | 97 +++++++++++++++++++++++++++++++++++++++
1 file changed, 97 insertions(+)

diff --git a/drivers/iommu/intel-iommu-debug.c b/drivers/iommu/intel-iommu-debug.c
index ef46820..295cadc 100644
--- a/drivers/iommu/intel-iommu-debug.c
+++ b/drivers/iommu/intel-iommu-debug.c
@@ -161,6 +161,94 @@ static const struct file_operations intel_iommu_debug_fops = {
.owner = THIS_MODULE,
};

+static int intel_iommu_debugfs_regs_show(struct seq_file *m, void *unused)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ unsigned long long base;
+ int i;
+ struct regset {
+ int offset;
+ char *regs;
+ };
+
+ static const struct regset regstr[] = {{DMAR_VER_REG, "VER"},
+ {DMAR_CAP_REG, "CAP"},
+ {DMAR_ECAP_REG, "ECAP"},
+ {DMAR_GCMD_REG, "GCMD"},
+ {DMAR_GSTS_REG, "GSTS"},
+ {DMAR_RTADDR_REG, "RTADDR"},
+ {DMAR_CCMD_REG, "CCMD"},
+ {DMAR_FSTS_REG, "FSTS"},
+ {DMAR_FECTL_REG, "FECTL"},
+ {DMAR_FEDATA_REG, "FEDATA"},
+ {DMAR_FEADDR_REG, "FEADDR"},
+ {DMAR_FEUADDR_REG, "FEUADDR"},
+ {DMAR_AFLOG_REG, "AFLOG"},
+ {DMAR_PMEN_REG, "PMEN"},
+ {DMAR_PLMBASE_REG, "PLMBASE"},
+ {DMAR_PLMLIMIT_REG, "PLMLIMIT"},
+ {DMAR_PHMBASE_REG, "PHMBASE"},
+ {DMAR_PHMLIMIT_REG, "PHMLIMIT"},
+ {DMAR_IQH_REG, "IQH"},
+ {DMAR_IQT_REG, "IQT"},
+ {DMAR_IQ_SHIFT, "IQ"},
+ {DMAR_IQA_REG, "IQA"},
+ {DMAR_ICS_REG, "ICS"},
+ {DMAR_IRTA_REG, "IRTA"},
+ {DMAR_PQH_REG, "PQH"},
+ {DMAR_PQT_REG, "PQT"},
+ {DMAR_PQA_REG, "PQA"},
+ {DMAR_PRS_REG, "PRS"},
+ {DMAR_PECTL_REG, "PECTL"},
+ {DMAR_PEDATA_REG, "PEDATA"},
+ {DMAR_PEADDR_REG, "PEADDR"},
+ {DMAR_PEUADDR_REG, "PEUADDR"} };
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (iommu) {
+ if (!drhd->reg_base_addr) {
+ seq_printf(m, "IOMMU: Invalid base address\n");
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ base = drhd->reg_base_addr;
+ seq_printf(m, "\nDMAR: %s: reg_base_addr %llx\n",
+ iommu->name, base);
+ seq_printf(m, "%-12s %2s\t%8s\n", "Name", "Offset",
+ "Contents");
+ /*
+ * Publish the contents of the 64-bit hardware registers
+ * by adding the offset to the pointer(virtual addr)
+ */
+ for (i = 0 ; i < ARRAY_SIZE(regstr); i++) {
+ seq_printf(m, "%-12s 0x%02x\t0x%016lx\n",
+ regstr[i].regs, regstr[i].offset,
+ readq(iommu->reg + regstr[i].offset)
+ );
+ }
+ }
+ }
+
+ rcu_read_unlock();
+ return 0;
+}
+
+static int intel_iommu_regs_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, intel_iommu_debugfs_regs_show,
+ inode->i_private);
+}
+
+static const struct file_operations intel_iommu_regs_fops = {
+ .open = intel_iommu_regs_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
void __init intel_iommu_debugfs_init(void)
{
struct dentry *iommu_debug_root;
@@ -178,6 +266,15 @@ void __init intel_iommu_debugfs_init(void)
goto err;
}

+ if (!debugfs_create_file("intel_iommu_regset", S_IRUGO,
+ iommu_debug_root, NULL, &intel_iommu_regs_fops
+ )) {
+ pr_err("Can't create intel_iommu_regset file\n");
+ goto err;
+ }
+
+ return;
+
err:
debugfs_remove_recursive(iommu_debug_root);

--
2.7.4
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