arch/x86/xen/pci-swiotlb-xen.c

   1 /* Glue code to lib/swiotlb-xen.c */
   2
   3 #include <linux/dma-mapping.h>
   4 #include <linux/pci.h>
   5 #include <xen/swiotlb-xen.h>
   6
   7 #include <asm/xen/hypervisor.h>
   8 #include <xen/xen.h>
   9 #include <asm/iommu_table.h>
  10
  11 int xen_swiotlb __read_mostly;
  12
  13 static struct dma_map_ops xen_swiotlb_dma_ops = {
  14         .mapping_error = xen_swiotlb_dma_mapping_error,
  15         .alloc_coherent = xen_swiotlb_alloc_coherent,
  16         .free_coherent = xen_swiotlb_free_coherent,
  17         .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
  18         .sync_single_for_device = xen_swiotlb_sync_single_for_device,
  19         .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
  20         .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
  21         .map_sg = xen_swiotlb_map_sg_attrs,
  22         .unmap_sg = xen_swiotlb_unmap_sg_attrs,
  23         .map_page = xen_swiotlb_map_page,
  24         .unmap_page = xen_swiotlb_unmap_page,
  25         .dma_supported = xen_swiotlb_dma_supported,
  26 };
  27
  28 /*
  29  * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
  30  *
  31  * This returns non-zero if we are forced to use xen_swiotlb (by the boot
  32  * option).
  33  */
  34 int __init pci_xen_swiotlb_detect(void)
  35 {
  36
  37         /* If running as PV guest, either iommu=soft, or swiotlb=force will
  38          * activate this IOMMU. If running as PV privileged, activate it
  39          * irregardless.
  40          */
  41         if ((xen_initial_domain() || swiotlb || swiotlb_force) &&
  42             (xen_pv_domain()))
  43                 xen_swiotlb = 1;
  44
  45         /* If we are running under Xen, we MUST disable the native SWIOTLB.
  46          * Don't worry about swiotlb_force flag activating the native, as
  47          * the 'swiotlb' flag is the only one turning it on. */
  48         if (xen_pv_domain())
  49                 swiotlb = 0;
  50
  51         return xen_swiotlb;
  52 }
  53
  54 void __init pci_xen_swiotlb_init(void)
  55 {
  56         if (xen_swiotlb) {
  57                 xen_swiotlb_init(1);
  58                 dma_ops = &xen_swiotlb_dma_ops;
  59
  60                 /* Make sure ACS will be enabled */
  61                 pci_request_acs();
  62         }
  63 }
  64 IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
  65                   0,
  66                   pci_xen_swiotlb_init,
  67                   0);