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

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Date:   Thu, 28 Nov 2019 10:25:49 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Alex Williamson <alex.williamson@...hat.com>
Cc:     ashok.raj@...el.com, sanjay.k.kumar@...el.com,
        jacob.jun.pan@...ux.intel.com, kevin.tian@...el.com,
        yi.l.liu@...el.com, yi.y.sun@...el.com,
        Peter Xu <peterx@...hat.com>, iommu@...ts.linux-foundation.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>,
        Yi Sun <yi.y.sun@...ux.intel.com>
Subject: [PATCH v2 7/8] iommu/vt-d: Identify domains using first level page table

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@...el.com>
Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: Kevin Tian <kevin.tian@...el.com>
Cc: Liu Yi L <yi.l.liu@...el.com>
Cc: Yi Sun <yi.y.sun@...ux.intel.com>
Cc: Sanjay Kumar <sanjay.k.kumar@...el.com>
Signed-off-by: Lu Baolu <baolu.lu@...ux.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