amd-iommu: handle exlusion ranges and unity mappings in alloc_new_range

This patch makes sure no reserved addresses are allocated in an dma_ops
domain when the aperture is increased dynamically.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 8ff02ee..59ee1b9 100644 (file)
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -58,6 +58,9 @@ static struct dma_ops_domain *find_protection_domain(u16 devid);
 static u64* alloc_pte(struct protection_domain *dom,
                      unsigned long address, u64
                      **pte_page, gfp_t gfp);
+static void dma_ops_reserve_addresses(struct dma_ops_domain *dom,
+                                     unsigned long start_page,
+                                     unsigned int pages);
 
 #ifdef CONFIG_AMD_IOMMU_STATS
 
@@ -621,14 +624,42 @@ static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom,
  */
 
 /*
+ * This function checks if there is a PTE for a given dma address. If
+ * there is one, it returns the pointer to it.
+ */
+static u64* fetch_pte(struct protection_domain *domain,
+                     unsigned long address)
+{
+       u64 *pte;
+
+       pte = &domain->pt_root[IOMMU_PTE_L2_INDEX(address)];
+
+       if (!IOMMU_PTE_PRESENT(*pte))
+               return NULL;
+
+       pte = IOMMU_PTE_PAGE(*pte);
+       pte = &pte[IOMMU_PTE_L1_INDEX(address)];
+
+       if (!IOMMU_PTE_PRESENT(*pte))
+               return NULL;
+
+       pte = IOMMU_PTE_PAGE(*pte);
+       pte = &pte[IOMMU_PTE_L0_INDEX(address)];
+
+       return pte;
+}
+
+/*
  * This function is used to add a new aperture range to an existing
  * aperture in case of dma_ops domain allocation or address allocation
  * failure.
  */
-static int alloc_new_range(struct dma_ops_domain *dma_dom,
+static int alloc_new_range(struct amd_iommu *iommu,
+                          struct dma_ops_domain *dma_dom,
                           bool populate, gfp_t gfp)
 {
        int index = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
+       int i;
 
        if (index >= APERTURE_MAX_RANGES)
                return -ENOMEM;
@@ -662,6 +693,33 @@ static int alloc_new_range(struct dma_ops_domain *dma_dom,
 
        dma_dom->aperture_size += APERTURE_RANGE_SIZE;
 
+       /* Intialize the exclusion range if necessary */
+       if (iommu->exclusion_start &&
+           iommu->exclusion_start >= dma_dom->aperture[index]->offset &&
+           iommu->exclusion_start < dma_dom->aperture_size) {
+               unsigned long startpage = iommu->exclusion_start >> PAGE_SHIFT;
+               int pages = iommu_num_pages(iommu->exclusion_start,
+                                           iommu->exclusion_length,
+                                           PAGE_SIZE);
+               dma_ops_reserve_addresses(dma_dom, startpage, pages);
+       }
+
+       /*
+        * Check for areas already mapped as present in the new aperture
+        * range and mark those pages as reserved in the allocator. Such
+        * mappings may already exist as a result of requested unity
+        * mappings for devices.
+        */
+       for (i = dma_dom->aperture[index]->offset;
+            i < dma_dom->aperture_size;
+            i += PAGE_SIZE) {
+               u64 *pte = fetch_pte(&dma_dom->domain, i);
+               if (!pte || !IOMMU_PTE_PRESENT(*pte))
+                       continue;
+
+               dma_ops_reserve_addresses(dma_dom, i << PAGE_SHIFT, 1);
+       }
+
        return 0;
 
 out_free:
@@ -911,7 +969,7 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu,
        dma_dom->need_flush = false;
        dma_dom->target_dev = 0xffff;
 
-       if (alloc_new_range(dma_dom, true, GFP_KERNEL))
+       if (alloc_new_range(iommu, dma_dom, true, GFP_KERNEL))
                goto free_dma_dom;
 
        /*
@@ -921,15 +979,6 @@ static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu,
        dma_dom->aperture[0]->bitmap[0] = 1;
        dma_dom->next_address = 0;
 
-       /* Intialize the exclusion range if necessary */
-       if (iommu->exclusion_start &&
-           iommu->exclusion_start < dma_dom->aperture_size) {
-               unsigned long startpage = iommu->exclusion_start >> PAGE_SHIFT;
-               int pages = iommu_num_pages(iommu->exclusion_start,
-                                           iommu->exclusion_length,
-                                           PAGE_SIZE);
-               dma_ops_reserve_addresses(dma_dom, startpage, pages);
-       }
 
        return dma_dom;