[PATCH 5.4 074/155] iommu/vt-d: Populate debugfs if IOMMUs are detected

Greg Kroah-Hartman
2020-03-31T09:14:33Z

From: Megha Dey <megha.dey@linux.intel.com>

[ 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>
---
drivers/iommu/intel-iommu-debugfs.c | 11 ++++++++++-
drivers/iommu/intel-iommu.c | 4 +++-
2 files changed, 13 insertions(+), 2 deletions(-)

--- 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 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(st
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(st
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);
--- 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;