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 */
pci_xen_swiotlb_detect(void)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
pci_xen_swiotlb_init(void)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
pci_xen_swiotlb_init_late(void)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);
110