iommu/vt-d: Populate debugfs if IOMMUs are detected

BugLink: https://bugs.launchpad.net/bugs/1870142
[ Upstream commit 1da8347d8505c137fb07ff06bbcd3f2bf37409bc ]

Currently, the intel iommu debugfs directory(/sys/kernel/debug/iommu/intel)
gets populated only when DMA remapping is enabled (dmar_disabled = 0)
irrespective of whether interrupt remapping is enabled or not.

Instead, populate the intel iommu debugfs directory if any IOMMUs are
detected.

Cc: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: ee2636b8670b1 ("iommu/vt-d: Enable base Intel IOMMU debugfs support")
Signed-off-by: Megha Dey <megha.dey@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

diff --git a/drivers/iommu/intel-iommu-debugfs.c b/drivers/iommu/intel-iommu-debugfs.c
index 80378c10dd77aa02c8c7658a5da09c45626cb3d3..bdf095e9dbe0308e6ce0a0af99543d6b0a879847 100644 (file)
--- a/drivers/iommu/intel-iommu-debugfs.c
+++ b/drivers/iommu/intel-iommu-debugfs.c
@@ -281,9 +281,16 @@ static int dmar_translation_struct_show(struct seq_file *m, void *unused)
 {
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;
+       u32 sts;
 
        rcu_read_lock();
        for_each_active_iommu(iommu, drhd) {
+               sts = dmar_readl(iommu->reg + DMAR_GSTS_REG);
+               if (!(sts & DMA_GSTS_TES)) {
+                       seq_printf(m, "DMA Remapping is not enabled on %s\n",
+                                  iommu->name);
+                       continue;
+               }
                root_tbl_walk(m, iommu);
                seq_putc(m, '\n');
        }
@@ -353,6 +360,7 @@ static int ir_translation_struct_show(struct seq_file *m, void *unused)
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;
        u64 irta;
+       u32 sts;
 
        rcu_read_lock();
        for_each_active_iommu(iommu, drhd) {
@@ -362,7 +370,8 @@ static int ir_translation_struct_show(struct seq_file *m, void *unused)
                seq_printf(m, "Remapped Interrupt supported on IOMMU: %s\n",
                           iommu->name);
 
-               if (iommu->ir_table) {
+               sts = dmar_readl(iommu->reg + DMAR_GSTS_REG);
+               if (iommu->ir_table && (sts & DMA_GSTS_IRES)) {
                        irta = virt_to_phys(iommu->ir_table->base);
                        seq_printf(m, " IR table address:%llx\n", irta);
                        ir_tbl_remap_entry_show(m, iommu);

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 1c2b3e78056f4873b5e7e608c8cd0677eeb2f939..9d47b227e5578ea2df64670a8115f7cf6ed3c4f5 100644 (file)
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4961,6 +4961,9 @@ int __init intel_iommu_init(void)
 
        down_write(&dmar_global_lock);
 
+       if (!no_iommu)
+               intel_iommu_debugfs_init();
+
        if (no_iommu || dmar_disabled) {
                /*
                 * We exit the function here to ensure IOMMU's remapping and
@@ -5056,7 +5059,6 @@ int __init intel_iommu_init(void)
        pr_info("Intel(R) Virtualization Technology for Directed I/O\n");
 
        intel_iommu_enabled = 1;
-       intel_iommu_debugfs_init();
 
        return 0;