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Date:   Mon, 4 Mar 2019 15:47:18 +0000
From:   James Sewart <jamessewart@...sta.com>
To:     iommu@...ts.linux-foundation.org
Cc:     Tom Murphy <tmurphy@...sta.com>, Dmitry Safonov <dima@...sta.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 4/4] iommu/vt-d: Remove lazy allocation of domains

The generic IOMMU code will allocate and attach a dma ops domain to each
device that comes online, replacing any lazy allocated domain. Removes
RMRR application at iommu init time as we won't have a domain attached
to any device. iommu.c will do this after attaching a device using
create_direct_mappings.

Signed-off-by: James Sewart <jamessewart@...sta.com>
---
 drivers/iommu/intel-iommu.c | 202 ++----------------------------------
 1 file changed, 8 insertions(+), 194 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 71cd6bbfec05..282257e2628d 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -2595,118 +2595,6 @@ 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 = NULL;
-	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)
@@ -2779,7 +2667,7 @@ static int iommu_prepare_identity_map(struct device *dev,
 	struct dmar_domain *domain;
 	int ret;
 
-	domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
+	domain = find_domain(dev);
 	if (!domain)
 		return -ENOMEM;
 
@@ -3301,11 +3189,9 @@ 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 intel_iommu *iommu;
-	int i, ret;
+	int ret;
 
 	/*
 	 * for each drhd
@@ -3466,32 +3352,6 @@ 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");
-		}
-	}
-
-	iommu_prepare_isa();
 
 domains_done:
 
@@ -3580,53 +3440,6 @@ 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)
-		pr_err("Allocating domain for %s failed\n", dev_name(dev));
-
-
-	return domain;
-}
-
 /* Check if the dev needs to go through non-identity map and unmap process.*/
 static int iommu_no_mapping(struct device *dev)
 {
@@ -3689,7 +3502,7 @@ static dma_addr_t __intel_map_page(struct device *dev, struct page *page,
 	if (iommu_no_mapping(dev))
 		return paddr;
 
-	domain = get_valid_domain_for_dev(dev);
+	domain = find_domain(dev);
 	if (!domain)
 		return DMA_MAPPING_ERROR;
 
@@ -3753,7 +3566,8 @@ static void intel_unmap(struct device *dev, dma_addr_t dev_addr, size_t size)
 		return;
 
 	domain = find_domain(dev);
-	BUG_ON(!domain);
+	if (!domain)
+		return;
 
 	iommu = domain_get_iommu(domain);
 
@@ -3899,7 +3713,7 @@ 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);
+	domain = find_domain(dev);
 	if (!domain)
 		return 0;
 
@@ -5377,9 +5191,9 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev *sd
 	u64 ctx_lo;
 	int ret;
 
-	domain = get_valid_domain_for_dev(sdev->dev);
+	domain = find_domain(sdev->dev);
 	if (!domain)
-		return -EINVAL;
+		return -ENOMEM;
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	spin_lock(&iommu->lock);
-- 
2.17.1

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