From 44a879dae8c246cd52fa754e99a1d43bc019c757 Mon Sep 17 00:00:00 2001
From: James Sewart <jamessewart@arista.com>
Date: Mon, 11 Mar 2019 14:55:01 +0000
Subject: [PATCH 9/9] iommu/vt-d: Remove lazy allocation of domains

The generic IOMMU code will allocate and attach a default domain to each
device that comes online. This patch removes the lazy domain allocation
and early reserved region mapping that is now redundant.

Signed-off-by: James Sewart <jamessewart@arista.com>

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 2055c11f5978..4bf719a82b64 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2463,21 +2463,6 @@ static void domain_remove_dev_info(struct dmar_domain *domain)
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
-/*
- * find_domain
- * Note: we use struct device->archdata.iommu stores the info
- */
-static struct dmar_domain *find_domain(struct device *dev)
-{
-	struct device_domain_info *info;
-
-	/* No lock here, assumes no domain exit in normal case */
-	info = dev->archdata.iommu;
-	if (likely(info))
-		return info->domain;
-	return NULL;
-}
-
 static inline struct device_domain_info *
 dmar_search_domain_by_dev_info(int segment, int bus, int devfn)
 {
@@ -2539,8 +2524,11 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
 	}
 
 	spin_lock_irqsave(&device_domain_lock, flags);
-	if (dev)
-		found = find_domain(dev);
+	if (dev) {
+		struct iommu_domain *io_domain = iommu_get_domain_for_dev(dev);
+		if (io_domain)
+			found = to_dmar_domain(io_domain);
+	}
 
 	if (!found) {
 		struct device_domain_info *info2;
@@ -2608,118 +2596,6 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
 	return domain;
 }
 
-static int get_last_alias(struct pci_dev *pdev, u16 alias, void *opaque)
-{
-	*(u16 *)opaque = alias;
-	return 0;
-}
-
-static struct dmar_domain *find_or_alloc_domain(struct device *dev, int gaw)
-{
-	struct device_domain_info *info;
-	struct dmar_domain *domain = NULL;
-	struct intel_iommu *iommu;
-	u16 dma_alias;
-	unsigned long flags;
-	u8 bus, devfn;
-
-	iommu = device_to_iommu(dev, &bus, &devfn);
-	if (!iommu)
-		return NULL;
-
-	if (dev_is_pci(dev)) {
-		struct pci_dev *pdev = to_pci_dev(dev);
-
-		pci_for_each_dma_alias(pdev, get_last_alias, &dma_alias);
-
-		spin_lock_irqsave(&device_domain_lock, flags);
-		info = dmar_search_domain_by_dev_info(pci_domain_nr(pdev->bus),
-						      PCI_BUS_NUM(dma_alias),
-						      dma_alias & 0xff);
-		if (info) {
-			iommu = info->iommu;
-			domain = info->domain;
-		}
-		spin_unlock_irqrestore(&device_domain_lock, flags);
-
-		/* DMA alias already has a domain, use it */
-		if (info)
-			goto out;
-	}
-
-	/* Allocate and initialize new domain for the device */
-	domain = alloc_domain(0);
-	if (!domain)
-		return NULL;
-	if (domain_init(domain, iommu, gaw)) {
-		domain_exit(domain);
-		return NULL;
-	}
-
-out:
-
-	return domain;
-}
-
-static struct dmar_domain *set_domain_for_dev(struct device *dev,
-					      struct dmar_domain *domain)
-{
-	struct intel_iommu *iommu;
-	struct dmar_domain *tmp;
-	u16 req_id, dma_alias;
-	u8 bus, devfn;
-
-	iommu = device_to_iommu(dev, &bus, &devfn);
-	if (!iommu)
-		return NULL;
-
-	req_id = ((u16)bus << 8) | devfn;
-
-	if (dev_is_pci(dev)) {
-		struct pci_dev *pdev = to_pci_dev(dev);
-
-		pci_for_each_dma_alias(pdev, get_last_alias, &dma_alias);
-
-		/* register PCI DMA alias device */
-		if (req_id != dma_alias) {
-			tmp = dmar_insert_one_dev_info(iommu, PCI_BUS_NUM(dma_alias),
-					dma_alias & 0xff, NULL, domain);
-
-			if (!tmp || tmp != domain)
-				return tmp;
-		}
-	}
-
-	tmp = dmar_insert_one_dev_info(iommu, bus, devfn, dev, domain);
-	if (!tmp || tmp != domain)
-		return tmp;
-
-	return domain;
-}
-
-static struct dmar_domain *get_domain_for_dev(struct device *dev, int gaw)
-{
-	struct dmar_domain *domain, *tmp;
-
-	domain = find_domain(dev);
-	if (domain)
-		goto out;
-
-	domain = find_or_alloc_domain(dev, gaw);
-	if (!domain)
-		goto out;
-
-	tmp = set_domain_for_dev(dev, domain);
-	if (!tmp || domain != tmp) {
-		domain_exit(domain);
-		domain = tmp;
-	}
-
-out:
-
-	return domain;
-}
-
 static int iommu_domain_identity_map(struct dmar_domain *domain,
 				     unsigned long long start,
 				     unsigned long long end)
@@ -2745,72 +2621,6 @@ static int iommu_domain_identity_map(struct dmar_domain *domain,
 				DMA_PTE_READ|DMA_PTE_WRITE);
 }
 
-static int domain_prepare_identity_map(struct device *dev,
-				       struct dmar_domain *domain,
-				       unsigned long long start,
-				       unsigned long long end)
-{
-	/* For _hardware_ passthrough, don't bother. But for software
-	   passthrough, we do it anyway -- it may indicate a memory
-	   range which is reserved in E820, so which didn't get set
-	   up to start with in si_domain */
-	if (domain == si_domain && hw_pass_through) {
-		dev_warn(dev, "Ignoring identity map for HW passthrough [0x%Lx - 0x%Lx]\n",
-			 start, end);
-		return 0;
-	}
-
-	dev_info(dev, "Setting identity map [0x%Lx - 0x%Lx]\n", start, end);
-
-	if (end < start) {
-		WARN(1, "Your BIOS is broken; RMRR ends before it starts!\n"
-			"BIOS vendor: %s; Ver: %s; Product Version: %s\n",
-			dmi_get_system_info(DMI_BIOS_VENDOR),
-			dmi_get_system_info(DMI_BIOS_VERSION),
-		     dmi_get_system_info(DMI_PRODUCT_VERSION));
-		return -EIO;
-	}
-
-	if (end >> agaw_to_width(domain->agaw)) {
-		WARN(1, "Your BIOS is broken; RMRR exceeds permitted address width (%d bits)\n"
-		     "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
-		     agaw_to_width(domain->agaw),
-		     dmi_get_system_info(DMI_BIOS_VENDOR),
-		     dmi_get_system_info(DMI_BIOS_VERSION),
-		     dmi_get_system_info(DMI_PRODUCT_VERSION));
-		return -EIO;
-	}
-
-	return iommu_domain_identity_map(domain, start, end);
-}
-
-static int iommu_prepare_identity_map(struct device *dev,
-				      unsigned long long start,
-				      unsigned long long end)
-{
-	struct dmar_domain *domain;
-	int ret;
-
-	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
-	if (!domain)
-		return -ENOMEM;
-
-	ret = domain_prepare_identity_map(dev, domain, start, end);
-	if (ret)
-		domain_exit(domain);
-
-	return ret;
-}
-
-static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr,
-					 struct device *dev)
-{
-	if (dev->archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
-		return 0;
-	return iommu_prepare_identity_map(dev, rmrr->base_address,
-					  rmrr->end_address);
-}
-
 static inline struct iommu_resv_region *iommu_get_isa_resv_region(void)
 {
 	if (!isa_resv_region)
@@ -2821,29 +2631,6 @@ static inline struct iommu_resv_region *iommu_get_isa_resv_region(void)
 	return isa_resv_region;
 }
 
-#ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA
-static inline void iommu_prepare_isa(struct pci_dev *pdev)
-{
-	int ret;
-	struct iommu_resv_region *reg = iommu_get_isa_resv_region();
-
-	if (!reg)
-		return;
-
-	pr_info("Prepare 0-16MiB unity mapping for LPC\n");
-	ret = iommu_prepare_identity_map(&pdev->dev, reg->start,
-			reg->start + reg->length - 1);
-
-	if (ret)
-		pr_err("Failed to create 0-16MiB identity map - floppy might not work\n");
-}
-#else
-static inline void iommu_prepare_isa(struct pci_dev *pdev)
-{
-	return;
-}
-#endif /* !CONFIG_INTEL_IOMMU_FLPY_WA */
-
 static int md_domain_init(struct dmar_domain *domain, int guest_width);
 
 static int __init si_domain_init(int hw)
@@ -3066,18 +2853,10 @@ static int __init dev_prepare_static_identity_mapping(struct device *dev, int hw
 
 static int __init iommu_prepare_static_identity_mapping(int hw)
 {
-	struct pci_dev *pdev = NULL;
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu;
 	struct device *dev;
-	int i;
-	int ret = 0;
-
-	for_each_pci_dev(pdev) {
-		ret = dev_prepare_static_identity_mapping(&pdev->dev, hw);
-		if (ret)
-			return ret;
-	}
+	int i, ret = 0;
 
 	for_each_active_iommu(iommu, drhd)
 		for_each_active_dev_scope(drhd->devices, drhd->devices_cnt, i, dev) {
@@ -3324,12 +3103,9 @@ static int copy_translation_tables(struct intel_iommu *iommu)
 static int __init init_dmars(void)
 {
 	struct dmar_drhd_unit *drhd;
-	struct dmar_rmrr_unit *rmrr;
 	bool copied_tables = false;
-	struct device *dev;
-	struct pci_dev *pdev;
 	struct intel_iommu *iommu;
-	int i, ret;
+	int ret;
 
 	/*
 	 * for each drhd
@@ -3483,36 +3259,6 @@ static int __init init_dmars(void)
 			goto free_iommu;
 		}
 	}
-	/*
-	 * For each rmrr
-	 *   for each dev attached to rmrr
-	 *   do
-	 *     locate drhd for dev, alloc domain for dev
-	 *     allocate free domain
-	 *     allocate page table entries for rmrr
-	 *     if context not allocated for bus
-	 *           allocate and init context
-	 *           set present in root table for this bus
-	 *     init context with domain, translation etc
-	 *    endfor
-	 * endfor
-	 */
-	pr_info("Setting RMRR:\n");
-	for_each_rmrr_units(rmrr) {
-		/* some BIOS lists non-exist devices in DMAR table. */
-		for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
-					  i, dev) {
-			ret = iommu_prepare_rmrr_dev(rmrr, dev);
-			if (ret)
-				pr_err("Mapping reserved region failed\n");
-		}
-	}
-
-	pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
-	if (pdev) {
-		iommu_prepare_isa(pdev);
-		pci_dev_put(pdev);
-	}
 
 domains_done:
 
@@ -3595,53 +3341,6 @@ static unsigned long intel_alloc_iova(struct device *dev,
 	return iova_pfn;
 }
 
-struct dmar_domain *get_valid_domain_for_dev(struct device *dev)
-{
-	struct dmar_domain *domain, *tmp;
-	struct dmar_rmrr_unit *rmrr;
-	struct device *i_dev;
-	int i, ret;
-
-	domain = find_domain(dev);
-	if (domain)
-		goto out;
-
-	domain = find_or_alloc_domain(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
-	if (!domain)
-		goto out;
-
-	/* We have a new domain - setup possible RMRRs for the device */
-	rcu_read_lock();
-	for_each_rmrr_units(rmrr) {
-		for_each_active_dev_scope(rmrr->devices, rmrr->devices_cnt,
-					  i, i_dev) {
-			if (i_dev != dev)
-				continue;
-
-			ret = domain_prepare_identity_map(dev, domain,
-							  rmrr->base_address,
-							  rmrr->end_address);
-			if (ret)
-				dev_err(dev, "Mapping reserved region failed\n");
-		}
-	}
-	rcu_read_unlock();
-
-	tmp = set_domain_for_dev(dev, domain);
-	if (!tmp || domain != tmp) {
-		domain_exit(domain);
-		domain = tmp;
-	}
-
-out:
-
-	if (!domain)
-		dev_err(dev, "Allocating domain failed\n");
-
-
-	return domain;
-}
-
 /* Check if the dev needs to go through non-identity map and unmap process.*/
 static int iommu_no_mapping(struct device *dev)
 {
@@ -3688,6 +3387,7 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
 				     size_t size, int dir, u64 dma_mask)
 {
 	struct dmar_domain *domain;
+	struct iommu_domain *io_domain;
 	phys_addr_t start_paddr;
 	unsigned long iova_pfn;
 	int prot = 0;
@@ -3700,9 +3400,10 @@ static dma_addr_t __intel_map_single(struct device *dev, phys_addr_t paddr,
 	if (iommu_no_mapping(dev))
 		return paddr;
 
-	domain = get_valid_domain_for_dev(dev);
-	if (!domain)
+	io_domain = iommu_get_domain_for_dev(dev);
+	if (!io_domain)
 		return DMA_MAPPING_ERROR;
+	domain = to_dmar_domain(io_domain);
 
 	iommu = domain_get_iommu(domain);
 	size = aligned_nrpages(paddr, size);
@@ -3762,6 +3463,7 @@ static dma_addr_t intel_map_resource(struct device *dev, phys_addr_t phys_addr,
 static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
 {
 	struct dmar_domain *domain;
+	struct iommu_domain *io_domain;
 	unsigned long start_pfn, last_pfn;
 	unsigned long nrpages;
 	unsigned long iova_pfn;
@@ -3771,8 +3473,9 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
 	if (iommu_no_mapping(dev))
 		return;
 
-	domain = find_domain(dev);
-	BUG_ON(!domain);
+	io_domain = iommu_get_domain_for_dev(dev);
+	BUG_ON(!io_domain);
+	domain = to_dmar_domain(io_domain);
 
 	iommu = domain_get_iommu(domain);
 
@@ -3906,6 +3609,7 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
 {
 	int i;
 	struct dmar_domain *domain;
+	struct iommu_domain *io_domain;
 	size_t size = 0;
 	int prot = 0;
 	unsigned long iova_pfn;
@@ -3918,9 +3622,10 @@ static int intel_map_sg(struct device *dev, struct scatterlist *sglist, int nele
 	if (iommu_no_mapping(dev))
 		return intel_nontranslate_map_sg(dev, sglist, nelems, dir);
 
-	domain = get_valid_domain_for_dev(dev);
-	if (!domain)
+	io_domain = iommu_get_domain_for_dev(dev);
+	if (!io_domain)
 		return 0;
+	domain = to_dmar_domain(io_domain);
 
 	iommu = domain_get_iommu(domain);
 
@@ -4611,9 +4316,11 @@ static int device_notifier(struct notifier_block *nb,
 		return 0;
 
 	if (action == BUS_NOTIFY_REMOVED_DEVICE) {
-		domain = find_domain(dev);
-		if (!domain)
+		struct iommu_domain *io_domain;
+		io_domain = iommu_get_domain_for_dev(dev);
+		if (!io_domain)
 			return 0;
+		domain = to_dmar_domain(io_domain);
 
 		dmar_remove_one_dev_info(dev);
 		if (!domain_managed_externally(domain) &&
@@ -5143,9 +4850,11 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
 	/* normally dev is not mapped */
 	if (unlikely(domain_context_mapped(dev))) {
 		struct dmar_domain *old_domain;
+		struct iommu_domain *old_io_domain;
 
-		old_domain = find_domain(dev);
-		if (old_domain) {
+		old_io_domain = iommu_get_domain_for_dev(dev);
+		if (old_io_domain) {
+			old_domain = to_dmar_domain(old_io_domain);
 			rcu_read_lock();
 			dmar_remove_one_dev_info(dev);
 			rcu_read_unlock();
@@ -5416,13 +5125,15 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev *sd
 	struct device_domain_info *info;
 	struct context_entry *context;
 	struct dmar_domain *domain;
+	struct iommu_domain *io_domain;
 	unsigned long flags;
 	u64 ctx_lo;
 	int ret;
 
-	domain = get_valid_domain_for_dev(sdev->dev);
-	if (!domain)
+	io_domain = iommu_get_domain_for_dev(sdev->dev);
+	if (!io_domain)
 		return -EINVAL;
+	domain = to_dmar_domain(io_domain);
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	spin_lock(&iommu->lock);
-- 
2.17.1