[PATCH v11 08/10] iommu/vt-d: assign new page table for dma_map

[Li, Zhen-Hua]

When a device driver issues the first dma_map command for a device, we
assign a new and empty page-table, thus removing all mappings from the
old kernel for the device.

Signed-off-by: Li, Zhen-Hua <zhen-h...@hp.com>
---
 drivers/iommu/intel-iommu.c | 58 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 91545bf..3cc1027 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -396,6 +396,9 @@ static int copy_root_entry_table(struct intel_iommu *iommu);
 
 static int intel_iommu_load_translation_tables(struct intel_iommu *iommu);
 
+static void unmap_device_dma(struct dmar_domain *domain,
+                               struct device *dev,
+                               struct intel_iommu *iommu);
 static void iommu_check_pre_te_status(struct intel_iommu *iommu);
 static u8 g_translation_pre_enabled;
 
@@ -3115,6 +3118,7 @@ static struct iova *intel_alloc_iova(struct device *dev,
 static struct dmar_domain *__get_valid_domain_for_dev(struct device *dev)
 {
        struct dmar_domain *domain;
+       struct intel_iommu *iommu;
        int ret;
 
        domain = get_domain_for_dev(dev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
@@ -3124,14 +3128,30 @@ static struct dmar_domain 
*__get_valid_domain_for_dev(struct device *dev)
                return NULL;
        }
 
-       /* make sure context mapping is ok */
-       if (unlikely(!domain_context_mapped(dev))) {
-               ret = domain_context_mapping(domain, dev, 
CONTEXT_TT_MULTI_LEVEL);
-               if (ret) {
-                       printk(KERN_ERR "Domain context map for %s failed",
-                              dev_name(dev));
-                       return NULL;
-               }
+       /* if in kdump kernel, we need to unmap the mapped dma pages,
+        * detach this device first.
+        */
+       if (likely(domain_context_mapped(dev))) {
+               iommu = domain_get_iommu(domain);
+               if (iommu->pre_enabled_trans) {
+                       unmap_device_dma(domain, dev, iommu);
+
+                       domain = get_domain_for_dev(dev,
+                               DEFAULT_DOMAIN_ADDRESS_WIDTH);
+                       if (!domain) {
+                               pr_err("Allocating domain for %s failed",
+                                      dev_name(dev));
+                               return NULL;
+                       }
+               } else
+                       return domain;
+       }
+
+       ret = domain_context_mapping(domain, dev, CONTEXT_TT_MULTI_LEVEL);
+       if (ret) {
+               pr_err("Domain context map for %s failed",
+                      dev_name(dev));
+               return NULL;
        }
 
        return domain;
@@ -5168,6 +5188,28 @@ static int intel_iommu_load_translation_tables(struct 
intel_iommu *iommu)
        return ret;
 }
 
+static void unmap_device_dma(struct dmar_domain *domain,
+                               struct device *dev,
+                               struct intel_iommu *iommu)
+{
+       struct context_entry *ce;
+       struct iova *iova;
+       phys_addr_t phys_addr;
+       dma_addr_t dev_addr;
+       struct pci_dev *pdev;
+
+       pdev = to_pci_dev(dev);
+       ce = iommu_context_addr(iommu, pdev->bus->number, pdev->devfn, 1);
+       phys_addr = context_address_root(ce) << VTD_PAGE_SHIFT;
+       dev_addr = phys_to_dma(dev, phys_addr);
+
+       iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
+       if (iova)
+               intel_unmap(dev, dev_addr);
+
+       domain_remove_one_dev_info(domain, dev);
+}
+
 static void iommu_check_pre_te_status(struct intel_iommu *iommu)
 {
        u32 sts;
-- 
2.0.0-rc0

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