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>

1 files changed, 60 insertions, 11 deletions

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 8ff02ee69e86..59ee1b94a7ce 100644
--- 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;