Merge branch 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (59 commits)
  x86/gart: Do not select AGP for GART_IOMMU
  x86/amd-iommu: Initialize passthrough mode when requested
  x86/amd-iommu: Don't detach device from pt domain on driver unbind
  x86/amd-iommu: Make sure a device is assigned in passthrough mode
  x86/amd-iommu: Align locking between attach_device and detach_device
  x86/amd-iommu: Fix device table write order
  x86/amd-iommu: Add passthrough mode initialization functions
  x86/amd-iommu: Add core functions for pd allocation/freeing
  x86/dma: Mark iommu_pass_through as __read_mostly
  x86/amd-iommu: Change iommu_map_page to support multiple page sizes
  x86/amd-iommu: Support higher level PTEs in iommu_page_unmap
  x86/amd-iommu: Remove old page table handling macros
  x86/amd-iommu: Use 2-level page tables for dma_ops domains
  x86/amd-iommu: Remove bus_addr check in iommu_map_page
  x86/amd-iommu: Remove last usages of IOMMU_PTE_L0_INDEX
  x86/amd-iommu: Change alloc_pte to support 64 bit address space
  x86/amd-iommu: Introduce increase_address_space function
  x86/amd-iommu: Flush domains if address space size was increased
  x86/amd-iommu: Introduce set_dte_entry function
  x86/amd-iommu: Add a gneric version of amd_iommu_flush_all_devices
  ...

1 files changed, 9 insertions, 2 deletions

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index fa80f60e9607..d71c8655905b 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -33,7 +33,14 @@ int no_iommu __read_mostly;
 /* Set this to 1 if there is a HW IOMMU in the system */
 int iommu_detected __read_mostly = 0;
 
-int iommu_pass_through;
+/*
+ * This variable becomes 1 if iommu=pt is passed on the kernel command line.
+ * If this variable is 1, IOMMU implementations do no DMA ranslation for
+ * devices and allow every device to access to whole physical memory. This is
+ * useful if a user want to use an IOMMU only for KVM device assignment to
+ * guests and not for driver dma translation.
+ */
+int iommu_pass_through __read_mostly;
 
 dma_addr_t bad_dma_address __read_mostly = 0;
 EXPORT_SYMBOL(bad_dma_address);
@@ -153,7 +160,7 @@ again:
                 return NULL;
 
         addr = page_to_phys(page);
-        if (!is_buffer_dma_capable(dma_mask, addr, size)) {
+        if (addr + size > dma_mask) {
                 __free_pages(page, get_order(size));
 
                 if (dma_mask < DMA_BIT_MASK(32) && !(flag & GFP_DMA)) {