[PATCH v2 7/8] iommu/vt-d: Identify domains using first level page table

Lu Baolu
2019-11-28T02:30:20Z

This checks whether a domain should use first level page table
for map/unmap. And if so, we should attach the domain to the
device in first level translation mode.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Cc: Yi Sun <yi.y.sun@linux.intel.com>
Cc: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 63 +++++++++++++++++++++++++++++++++++--
1 file changed, 60 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 695a7a5fbe8e..68b2f98ecd65 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -417,6 +417,11 @@ const struct iommu_ops intel_iommu_ops;
static const struct pgtable_ops first_lvl_pgtable_ops;
static const struct pgtable_ops second_lvl_pgtable_ops;

+static inline bool domain_pgtable_first_lvl(struct dmar_domain *domain)
+{
+ return domain->ops == &first_lvl_pgtable_ops;
+}
+
static bool translation_pre_enabled(struct intel_iommu *iommu)
{
return (iommu->flags & VTD_FLAG_TRANS_PRE_ENABLED);
@@ -1702,6 +1707,44 @@ static bool first_lvl_5lp_support(void)
return first_level_5lp_supported;
}

+/*
+ * Check and return whether first level is used by default for
+ * DMA translation.
+ */
+static bool first_level_by_default(void)
+{
+ struct dmar_drhd_unit *drhd;
+ struct intel_iommu *iommu;
+ static int first_level_support = -1;
+
+ if (likely(first_level_support != -1))
+ return first_level_support;
+
+ first_level_support = 1;
+
+ rcu_read_lock();
+ for_each_active_iommu(iommu, drhd) {
+ if (!sm_supported(iommu) || !ecap_flts(iommu->ecap)) {
+ first_level_support = 0;
+ break;
+ }
+#ifdef CONFIG_X86
+ /*
+ * Currently we don't support paging mode missmatching.
+ * Could be turned on later if there is a case.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_LA57) &&
+ !cap_5lp_support(iommu->cap)) {
+ first_level_support = 0;
+ break;
+ }
+#endif /* #ifdef CONFIG_X86 */
+ }
+ rcu_read_unlock();
+
+ return first_level_support;
+}
+
static struct dmar_domain *alloc_domain(int flags)
{
struct dmar_domain *domain;
@@ -1714,7 +1757,10 @@ static struct dmar_domain *alloc_domain(int flags)
domain->nid = NUMA_NO_NODE;
domain->flags = flags;
domain->has_iotlb_device = false;
- domain->ops = &second_lvl_pgtable_ops;
+ if (first_level_by_default())
+ domain->ops = &first_lvl_pgtable_ops;
+ else
+ domain->ops = &second_lvl_pgtable_ops;
domain->first_lvl_5lp = first_lvl_5lp_support();
spin_lock_init(&domain->page_table_lock);
INIT_LIST_HEAD(&domain->devices);
@@ -2710,6 +2756,11 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
if (hw_pass_through && domain_type_is_si(domain))
ret = intel_pasid_setup_pass_through(iommu, domain,
dev, PASID_RID2PASID);
+ else if (domain_pgtable_first_lvl(domain))
+ ret = intel_pasid_setup_first_level(iommu, dev,
+ domain->pgd, PASID_RID2PASID,
+ domain->iommu_did[iommu->seq_id],
+ PASID_FLAG_SUPERVISOR_MODE);
else
ret = intel_pasid_setup_second_level(iommu, domain,
dev, PASID_RID2PASID);
@@ -5597,8 +5648,14 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
goto attach_failed;

/* Setup the PASID entry for mediated devices: */
- ret = intel_pasid_setup_second_level(iommu, domain, dev,
- domain->default_pasid);
+ if (domain_pgtable_first_lvl(domain))
+ ret = intel_pasid_setup_first_level(iommu, dev,
+ domain->pgd, domain->default_pasid,
+ domain->iommu_did[iommu->seq_id],
+ PASID_FLAG_SUPERVISOR_MODE);
+ else
+ ret = intel_pasid_setup_second_level(iommu, domain, dev,
+ domain->default_pasid);
if (ret)
goto table_failed;
spin_unlock(&iommu->lock);
--
2.17.1