intel-iommu: Introduce domain_pfn_mapping()

... and use it in the trivial cases; the other callers want individual
(and bisectable) attention, since I screwed them up the first time...

Make the BUG_ON() happen on too-large virtual address rather than
physical address, too. That's the one we care about.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index f08d7865fe00..7540ef91d5f7 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -1643,40 +1643,48 @@ static int domain_context_mapped(struct pci_dev *pdev)
                                              tmp->devfn);
 }
 
-static int
-domain_page_mapping(struct dmar_domain *domain, dma_addr_t iova,
-                        u64 hpa, size_t size, int prot)
+static int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
+                              unsigned long phys_pfn, unsigned long nr_pages,
+                              int prot)
 {
-        unsigned long start_pfn = hpa >> VTD_PAGE_SHIFT;
-        unsigned long last_pfn = (hpa + size - 1) >> VTD_PAGE_SHIFT;
         struct dma_pte *pte;
-        int index = 0;
         int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
 
-        BUG_ON(addr_width < BITS_PER_LONG && last_pfn >> addr_width);
+        BUG_ON(addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1) >> addr_width);
 
         if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
                 return -EINVAL;
 
-        while (start_pfn <= last_pfn) {
-                pte = pfn_to_dma_pte(domain, (iova >> VTD_PAGE_SHIFT) + index);
+        while (nr_pages--) {
+                pte = pfn_to_dma_pte(domain, iov_pfn);
                 if (!pte)
                         return -ENOMEM;
                 /* We don't need lock here, nobody else
                  * touches the iova range
                  */
                 BUG_ON(dma_pte_addr(pte));
-                dma_set_pte_pfn(pte, start_pfn);
+                dma_set_pte_pfn(pte, phys_pfn);
                 dma_set_pte_prot(pte, prot);
                 if (prot & DMA_PTE_SNP)
                         dma_set_pte_snp(pte);
                 domain_flush_cache(domain, pte, sizeof(*pte));
-                start_pfn++;
-                index++;
+                iov_pfn++;
+                phys_pfn++;
         }
         return 0;
 }
 
+static int domain_page_mapping(struct dmar_domain *domain, dma_addr_t iova,
+                               u64 hpa, size_t size, int prot)
+{
+        unsigned long first_pfn = hpa >> VTD_PAGE_SHIFT;
+        unsigned long last_pfn = (hpa + size - 1) >> VTD_PAGE_SHIFT;
+
+        return domain_pfn_mapping(domain, iova >> VTD_PAGE_SHIFT, first_pfn,
+                                  last_pfn - first_pfn + 1, prot);
+
+}
+
 static void iommu_detach_dev(struct intel_iommu *iommu, u8 bus, u8 devfn)
 {
         if (!iommu)
@@ -1893,8 +1901,10 @@ static int iommu_domain_identity_map(struct dmar_domain *domain,
         dma_pte_clear_range(domain, base >> VTD_PAGE_SHIFT,
                             (base + size - 1) >> VTD_PAGE_SHIFT);
 
-        return domain_page_mapping(domain, base, base, size,
-                                   DMA_PTE_READ|DMA_PTE_WRITE);
+        return domain_pfn_mapping(domain, base >> VTD_PAGE_SHIFT,
+                                  base >> VTD_PAGE_SHIFT,
+                                  size >> VTD_PAGE_SHIFT,
+                                  DMA_PTE_READ|DMA_PTE_WRITE);
 }
 
 static int iommu_prepare_identity_map(struct pci_dev *pdev,