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
  12 #include <asm/xen/swiotlb-xen.h>
  13 #ifdef CONFIG_X86_64
  14 #include <asm/iommu.h>
  15 #include <asm/dma.h>
  16 #endif
  17 #include <linux/export.h>
  18
  19 int xen_swiotlb __read_mostly;
  20
  21 static struct dma_map_ops xen_swiotlb_dma_ops = {
  22         .mapping_error = xen_swiotlb_dma_mapping_error,
  23         .alloc = xen_swiotlb_alloc_coherent,
  24         .free = xen_swiotlb_free_coherent,
  25         .sync_single_for_cpu = xen_swiotlb_sync_single_for_cpu,
  26         .sync_single_for_device = xen_swiotlb_sync_single_for_device,
  27         .sync_sg_for_cpu = xen_swiotlb_sync_sg_for_cpu,
  28         .sync_sg_for_device = xen_swiotlb_sync_sg_for_device,
  29         .map_sg = xen_swiotlb_map_sg_attrs,
  30         .unmap_sg = xen_swiotlb_unmap_sg_attrs,
  31         .map_page = xen_swiotlb_map_page,
  32         .unmap_page = xen_swiotlb_unmap_page,
  33         .dma_supported = xen_swiotlb_dma_supported,
  34 };
  35
  36 /*
  37  * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
  38  *
  39  * This returns non-zero if we are forced to use xen_swiotlb (by the boot
  40  * option).
  41  */
  42 int __init pci_xen_swiotlb_detect(void)
  43 {
  44
  45         if (!xen_pv_domain())
  46                 return 0;
  47
  48         /* If running as PV guest, either iommu=soft, or swiotlb=force will
  49          * activate this IOMMU. If running as PV privileged, activate it
  50          * irregardless.
  51          */
  52         if ((xen_initial_domain() || swiotlb || swiotlb_force))
  53                 xen_swiotlb = 1;
  54
  55         /* If we are running under Xen, we MUST disable the native SWIOTLB.
  56          * Don't worry about swiotlb_force flag activating the native, as
  57          * the 'swiotlb' flag is the only one turning it on. */
  58         swiotlb = 0;
  59
  60 #ifdef CONFIG_X86_64
  61         /* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
  62          * (so no iommu=X command line over-writes).
  63          * Considering that PV guests do not want the *native SWIOTLB* but
  64          * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
  65          */
  66         if (max_pfn > MAX_DMA32_PFN)
  67                 no_iommu = 1;
  68 #endif
  69         return xen_swiotlb;
  70 }
  71
  72 void __init pci_xen_swiotlb_init(void)
  73 {
  74         if (xen_swiotlb) {
  75                 xen_swiotlb_init(1, true /* early */);
  76                 dma_ops = &xen_swiotlb_dma_ops;
  77
  78 #ifdef CONFIG_PCI
  79                 /* Make sure ACS will be enabled */
  80                 pci_request_acs();
  81 #endif
  82         }
  83 }
  84
  85 int pci_xen_swiotlb_init_late(void)
  86 {
  87         int rc;
  88
  89         if (xen_swiotlb)
  90                 return 0;
  91
  92         rc = xen_swiotlb_init(1, false /* late */);
  93         if (rc)
  94                 return rc;
  95
  96         dma_ops = &xen_swiotlb_dma_ops;
  97 #ifdef CONFIG_PCI
  98         /* Make sure ACS will be enabled */
  99         pci_request_acs();
 100 #endif
 101
 102         return 0;
 103 }
 104 EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
 105
 106 IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
 107                   NULL,
 108                   pci_xen_swiotlb_init,
 109                   NULL);