Re: [PATCH v4 5/7] iommu/vt-d: Make device pasid attachment explicit

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On 4/8/23 2:05 AM, Jacob Pan wrote:
@@ -2429,10 +2475,11 @@ static int __init si_domain_init(int hw)
  	return 0;
  }
-static int dmar_domain_attach_device(struct dmar_domain *domain,
-				     struct device *dev)
+static int dmar_domain_attach_device_pasid(struct dmar_domain *domain,
+				     struct device *dev, ioasid_t pasid)
  {
  	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct device_pasid_info *dev_pasid;
  	struct intel_iommu *iommu;
  	unsigned long flags;
  	u8 bus, devfn;
@@ -2442,43 +2489,57 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
  	if (!iommu)
  		return -ENODEV;
+ dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
+	if (!dev_pasid)
+		return -ENOMEM;
+
  	ret = domain_attach_iommu(domain, iommu);
  	if (ret)
-		return ret;
+		goto exit_free;
+
  	info->domain = domain;
+	dev_pasid->pasid = pasid;
+	dev_pasid->dev = dev;
  	spin_lock_irqsave(&domain->lock, flags);
-	list_add(&info->link, &domain->devices);
+	if (!info->dev_attached)
+		list_add(&info->link, &domain->devices);
+
+	list_add(&dev_pasid->link_domain, &domain->dev_pasids);
  	spin_unlock_irqrestore(&domain->lock, flags);
/* PASID table is mandatory for a PCI device in scalable mode. */
  	if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
  		/* Setup the PASID entry for requests without PASID: */
  		if (hw_pass_through && domain_type_is_si(domain))
-			ret = intel_pasid_setup_pass_through(iommu, domain,
-					dev, PASID_RID2PASID);
+			ret = intel_pasid_setup_pass_through(iommu, domain, dev, pasid);
  		else if (domain->use_first_level)
-			ret = domain_setup_first_level(iommu, domain, dev,
-					PASID_RID2PASID);
+			ret = domain_setup_first_level(iommu, domain, dev, pasid);
  		else
-			ret = intel_pasid_setup_second_level(iommu, domain,
-					dev, PASID_RID2PASID);
+			ret = intel_pasid_setup_second_level(iommu, domain, dev, pasid);
  		if (ret) {
-			dev_err(dev, "Setup RID2PASID failed\n");
+			dev_err(dev, "Setup PASID %d failed\n", pasid);
  			device_block_translation(dev);
-			return ret;
+			goto exit_free;
  		}
  	}
+	/* device context already activated,  we are done */
+	if (info->dev_attached)
+		goto exit;
ret = domain_context_mapping(domain, dev);
  	if (ret) {
  		dev_err(dev, "Domain context map failed\n");
  		device_block_translation(dev);
-		return ret;
+		goto exit_free;
  	}
iommu_enable_pci_caps(info);
-
+	info->dev_attached = 1;
+exit:
  	return 0;
+exit_free:
+	kfree(dev_pasid);
+	return ret;
  }
static bool device_has_rmrr(struct device *dev)
@@ -4029,8 +4090,7 @@ static void device_block_translation(struct device *dev)
  	iommu_disable_pci_caps(info);
  	if (!dev_is_real_dma_subdevice(dev)) {
  		if (sm_supported(iommu))
-			intel_pasid_tear_down_entry(iommu, dev,
-						    PASID_RID2PASID, false);
+			intel_iommu_detach_device_pasid(&info->domain->domain, dev, PASID_RID2PASID);
  		else
  			domain_context_clear(info);
  	}
@@ -4040,6 +4100,7 @@ static void device_block_translation(struct device *dev)
spin_lock_irqsave(&info->domain->lock, flags);
  	list_del(&info->link);
+	info->dev_attached = 0;
  	spin_unlock_irqrestore(&info->domain->lock, flags);
domain_detach_iommu(info->domain, iommu);
@@ -4186,7 +4247,7 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
  	if (ret)
  		return ret;
- return dmar_domain_attach_device(to_dmar_domain(domain), dev);
+	return dmar_domain_attach_device_pasid(to_dmar_domain(domain), dev, PASID_RID2PASID);
  }

For VT-d driver, attach_dev and attach_dev_pasid have different
meanings. Merging them into one helper may lead to confusion. What do
you think of the following code? The dmar_domain_attach_device_pasid()
helper could be reused for attach_dev_pasid path.

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 7c2f4bd33582..09ae62bc3724 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2434,6 +2434,40 @@ static int __init si_domain_init(int hw)
 	return 0;
 }

+
+static int dmar_domain_attach_device_pasid(struct dmar_domain *domain,
+					   struct intel_iommu *iommu,
+					   struct device *dev, ioasid_t pasid)
+{
+	struct device_pasid_info *dev_pasid;
+	unsigned long flags;
+	int ret;
+
+	dev_pasid = kzalloc(sizeof(*dev_pasid), GFP_KERNEL);
+	if (!dev_pasid)
+		return -ENOMEM;
+
+	if (hw_pass_through && domain_type_is_si(domain))
+		ret = intel_pasid_setup_pass_through(iommu, domain, dev, pasid);
+	else if (domain->use_first_level)
+		ret = domain_setup_first_level(iommu, domain, dev, pasid);
+	else
+		ret = intel_pasid_setup_second_level(iommu, domain, dev, pasid);
+
+	if (ret) {
+		kfree(dev_pasid);
+		return ret;
+	}
+
+	dev_pasid->pasid = pasid;
+	dev_pasid->dev = dev;
+	spin_lock_irqsave(&domain->lock, flags);
+	list_add(&dev_pasid->link_domain, &domain->dev_pasids);
+	spin_unlock_irqrestore(&domain->lock, flags);
+
+	return 0;
+}
+
 static int dmar_domain_attach_device(struct dmar_domain *domain,
 				     struct device *dev)
 {
@@ -2458,15 +2492,8 @@ static int dmar_domain_attach_device(struct dmar_domain *domain,
 	/* PASID table is mandatory for a PCI device in scalable mode. */
 	if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
 		/* Setup the PASID entry for requests without PASID: */
-		if (hw_pass_through && domain_type_is_si(domain))
-			ret = intel_pasid_setup_pass_through(iommu, domain,
-					dev, PASID_RID2PASID);
-		else if (domain->use_first_level)
-			ret = domain_setup_first_level(iommu, domain, dev,
-					PASID_RID2PASID);
-		else
-			ret = intel_pasid_setup_second_level(iommu, domain,
-					dev, PASID_RID2PASID);
+		ret = dmar_domain_attach_device_pasid(domain, iommu, dev,
+						      PASID_RID2PASID);
 		if (ret) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			device_block_translation(dev);

static int intel_iommu_map(struct iommu_domain *domain,
@@ -4675,26 +4736,52 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
  		__mapping_notify_one(info->iommu, dmar_domain, pfn, pages);
  }
-static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
+static void intel_iommu_detach_device_pasid(struct iommu_domain *domain,
+					    struct device *dev, ioasid_t pasid)
  {
-	struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL);
-	struct iommu_domain *domain;
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
+	struct device_pasid_info *i, *dev_pasid = NULL;
+	struct intel_iommu *iommu = info->iommu;
+	unsigned long flags;
- /* Domain type specific cleanup: */
-	domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
-	if (domain) {
-		switch (domain->type) {
-		case IOMMU_DOMAIN_SVA:
-			intel_svm_remove_dev_pasid(dev, pasid);
-			break;
-		default:
-			/* should never reach here */
-			WARN_ON(1);
+	spin_lock_irqsave(&dmar_domain->lock, flags);
+	list_for_each_entry(i, &dmar_domain->dev_pasids, link_domain) {
+		if (i->dev == dev && i->pasid == pasid) {
+			list_del(&i->link_domain);
+			dev_pasid = i;
  			break;
  		}
  	}
+	spin_unlock_irqrestore(&dmar_domain->lock, flags);
+	if (WARN_ON(!dev_pasid))
+		return;
+
+	/* PASID entry already cleared during SVA unbind */
+	if (domain->type != IOMMU_DOMAIN_SVA)
+		intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+
+	kfree(dev_pasid);
+}
+
+static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
+{
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct dmar_domain *dmar_domain;
+	struct iommu_domain *domain;
+
+	domain = iommu_get_domain_for_dev_pasid(dev, pasid, 0);
+	dmar_domain = to_dmar_domain(domain);
+
+	/*
+	 * SVA Domain type specific cleanup: Not ideal but not until we have
+	 * IOPF capable domain specific ops, we need this special case.
+	 */
+	if (domain->type == IOMMU_DOMAIN_SVA)
+		return intel_svm_remove_dev_pasid(dev, pasid);
- intel_pasid_tear_down_entry(iommu, dev, pasid, false);
+	intel_iommu_detach_device_pasid(domain, dev, pasid);
+	domain_detach_iommu(dmar_domain, info->iommu);
  }

The remove_dev_pasid path need to change only after attach_dev_pasid op
is added, right? If so, we should move such change into the next patch.

const struct iommu_ops intel_iommu_ops = {
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 65b15be72878..b6c26f25d1ba 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -595,6 +595,7 @@ struct dmar_domain {
spinlock_t lock; /* Protect device tracking lists */
  	struct list_head devices;	/* all devices' list */
+	struct list_head dev_pasids;	/* all attached pasids */
struct dma_pte *pgd; /* virtual address */
  	int		gaw;		/* max guest address width */
@@ -708,6 +709,7 @@ struct device_domain_info {
  	u8 ats_supported:1;
  	u8 ats_enabled:1;
  	u8 dtlb_extra_inval:1;	/* Quirk for devices need extra flush */
+	u8 dev_attached:1;	/* Device context activated */
  	u8 ats_qdep;
  	struct device *dev; /* it's NULL for PCIe-to-PCI bridge */
  	struct intel_iommu *iommu; /* IOMMU used by this device */
@@ -715,6 +717,12 @@ struct device_domain_info {
  	struct pasid_table *pasid_table; /* pasid table */
  };
+struct device_pasid_info {
+	struct list_head link_domain;	/* link to domain siblings */
+	struct device *dev;		/* physical device derived from */
+	ioasid_t pasid;			/* PASID on physical device */
+};
+
  static inline void __iommu_flush_cache(
  	struct intel_iommu *iommu, void *addr, int size)
  {

Best regards,
baolu



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