linux-kernel - [RFC PATCH 4/4] iommu/vt-d: Identify domains using first level page table

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Date:   Mon, 23 Sep 2019 20:24:54 +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,
        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: [RFC PATCH 4/4] 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 | 41 ++++++++++++++++++++++++++++++++++---
 1 file changed, 38 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 103480016010..d539e6a6c3dd 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1722,6 +1722,26 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
 #endif
 }
 
+/*
+ * 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;
+
+	rcu_read_lock();
+	for_each_active_iommu(iommu, drhd)
+		if (!sm_supported(iommu) ||
+		    !ecap_flts(iommu->ecap) ||
+		    !cap_caching_mode(iommu->cap))
+			return false;
+	rcu_read_unlock();
+
+	return true;
+}
+
 static struct dmar_domain *alloc_domain(int flags)
 {
 	struct dmar_domain *domain;
@@ -1736,6 +1756,9 @@ static struct dmar_domain *alloc_domain(int flags)
 	domain->has_iotlb_device = false;
 	INIT_LIST_HEAD(&domain->devices);
 
+	if (first_level_by_default())
+		domain->flags |= DOMAIN_FLAG_FIRST_LEVEL_TRANS;
+
 	return domain;
 }
 
@@ -2625,6 +2648,11 @@ 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_type_is_flt(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);
@@ -5349,8 +5377,14 @@ 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_type_is_flt(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);
@@ -5583,7 +5617,8 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
 	int level = 0;
 	u64 phys = 0;
 
-	if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN)
+	if ((dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN) ||
+	    (dmar_domain->flags & DOMAIN_FLAG_FIRST_LEVEL_TRANS))
 		return 0;
 
 	pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
-- 
2.17.1