[PATCH v3 1/4] iommu/vt-d: Implement domain ops for attach_dev_pasid

[Jacob Pan <jacob.jun.pan@linux.intel.com>]

On VT-d platforms with scalable mode enabled, devices issue DMA requests
with PASID need to attach PASIDs to given IOMMU domains. The attach
operation involves the following:
- Programming the PASID into the device's PASID table
- Tracking device domain and the PASID relationship
- Managing IOTLB and device TLB invalidations

This patch add attach_dev_pasid functions to the default domain ops which
is used by DMA and identity domain types. It could be extended to support
other domain types whenever necessary.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 81 ++++++++++++++++++++++++++++++++++++-
 include/linux/intel-iommu.h |  1 +
 2 files changed, 80 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index a51b96fa9b3a..5408418f4f4b 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1562,6 +1562,10 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
 
 	sid = info->bus << 8 | info->devfn;
 	qdep = info->ats_qdep;
+	if (info->pasid) {
+		qi_flush_dev_iotlb_pasid(info->iommu, sid, info->pfsid,
+					 info->pasid, qdep, addr, mask);
+	}
 	qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
 			   qdep, addr, mask);
 }
@@ -1591,6 +1595,7 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 	unsigned int mask = ilog2(aligned_pages);
 	uint64_t addr = (uint64_t)pfn << VTD_PAGE_SHIFT;
 	u16 did = domain->iommu_did[iommu->seq_id];
+	struct iommu_domain *iommu_domain = &domain->domain;
 
 	BUG_ON(pages == 0);
 
@@ -1599,6 +1604,9 @@ static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
 
 	if (domain_use_first_level(domain)) {
 		qi_flush_piotlb(iommu, did, PASID_RID2PASID, addr, pages, ih);
+		/* flush additional kernel DMA PASIDs attached */
+		if (iommu_domain->pasid)
+			qi_flush_piotlb(iommu, did, iommu_domain->pasid, addr, pages, ih);
 	} else {
 		unsigned long bitmask = aligned_pages - 1;
 
@@ -4265,10 +4273,13 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 	domain = info->domain;
 
 	if (info->dev && !dev_is_real_dma_subdevice(info->dev)) {
-		if (dev_is_pci(info->dev) && sm_supported(iommu))
+		if (dev_is_pci(info->dev) && sm_supported(iommu)) {
 			intel_pasid_tear_down_entry(iommu, info->dev,
 					PASID_RID2PASID, false);
-
+			if (info->pasid)
+				intel_pasid_tear_down_entry(iommu, info->dev,
+							    info->pasid, false);
+		}
 		iommu_disable_dev_iotlb(info);
 		domain_context_clear(info);
 		intel_pasid_free_table(info->dev);
@@ -4912,6 +4923,70 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
 	}
 }
 
+static int intel_iommu_attach_dev_pasid(struct iommu_domain *domain,
+					struct device *dev,
+					ioasid_t pasid)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+	struct intel_iommu *iommu = info->iommu;
+	unsigned long flags;
+	int ret = 0;
+
+	if (!sm_supported(iommu) || !info)
+		return -ENODEV;
+
+	spin_lock_irqsave(&device_domain_lock, flags);
+	/*
+	 * If the same device already has a PASID attached, just return.
+	 * DMA layer will return the PASID value to the caller.
+	 */
+	if (pasid != PASID_RID2PASID && info->pasid) {
+		if (info->pasid == pasid)
+			ret = 0;
+		else {
+			dev_warn(dev, "Cannot attach PASID %u, %u already attached\n",
+				 pasid, info->pasid);
+			ret = -EBUSY;
+		}
+		goto out_unlock_domain;
+	}
+
+	spin_lock(&iommu->lock);
+	if (hw_pass_through && domain_type_is_si(dmar_domain))
+		ret = intel_pasid_setup_pass_through(iommu, dmar_domain,
+						     dev, pasid);
+	else if (domain_use_first_level(dmar_domain))
+		ret = domain_setup_first_level(iommu, dmar_domain,
+					       dev, pasid);
+	else
+		ret = intel_pasid_setup_second_level(iommu, dmar_domain,
+						     dev, pasid);
+
+	spin_unlock(&iommu->lock);
+out_unlock_domain:
+	spin_unlock_irqrestore(&device_domain_lock, flags);
+	if (!ret)
+		info->pasid = pasid;
+
+	return ret;
+}
+
+static void intel_iommu_detach_dev_pasid(struct iommu_domain *domain,
+					struct device *dev,
+					ioasid_t pasid)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
+	unsigned long flags;
+
+	WARN_ON(info->pasid != pasid);
+	spin_lock_irqsave(&iommu->lock, flags);
+	intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+	info->pasid = 0;
+	spin_unlock_irqrestore(&iommu->lock, flags);
+}
+
 const struct iommu_ops intel_iommu_ops = {
 	.capable		= intel_iommu_capable,
 	.domain_alloc		= intel_iommu_domain_alloc,
@@ -4940,6 +5015,8 @@ const struct iommu_ops intel_iommu_ops = {
 		.iova_to_phys		= intel_iommu_iova_to_phys,
 		.free			= intel_iommu_domain_free,
 		.enforce_cache_coherency = intel_iommu_enforce_cache_coherency,
+		.attach_dev_pasid	= intel_iommu_attach_dev_pasid,
+		.detach_dev_pasid	= intel_iommu_detach_dev_pasid,
 	}
 };
 
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index 5af24befc9f1..55845a8c4f4d 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -627,6 +627,7 @@ struct device_domain_info {
 	struct intel_iommu *iommu; /* IOMMU used by this device */
 	struct dmar_domain *domain; /* pointer to domain */
 	struct pasid_table *pasid_table; /* pasid table */
+	ioasid_t pasid; /* DMA request with PASID */
 };
 
 static inline void __iommu_flush_cache(
-- 
2.25.1