1// SPDX-License-Identifier: GPL-2.0
2
3/* Glue code to lib/swiotlb-xen.c */
4
5#include <linux/dma-map-ops.h>
6#include <linux/pci.h>
7#include <xen/swiotlb-xen.h>
8
9#include <asm/xen/hypervisor.h>
10#include <xen/xen.h>
11#include <asm/iommu_table.h>
12
13
14#include <asm/xen/swiotlb-xen.h>
15#ifdef CONFIG_X86_64
16#include <asm/iommu.h>
17#include <asm/dma.h>
18#endif
19#include <linux/export.h>
20
21int xen_swiotlb __read_mostly;
22
23/*
24 * pci_xen_swiotlb_detect - set xen_swiotlb to 1 if necessary
25 *
26 * This returns non-zero if we are forced to use xen_swiotlb (by the boot
27 * option).
28 */
29int __init pci_xen_swiotlb_detect(void)
30{
31
32	if (!xen_pv_domain())
33		return 0;
34
35	/* If running as PV guest, either iommu=soft, or swiotlb=force will
36	 * activate this IOMMU. If running as PV privileged, activate it
37	 * irregardless.
38	 */
39	if (xen_initial_domain() || swiotlb || swiotlb_force == SWIOTLB_FORCE)
40		xen_swiotlb = 1;
41
42	/* If we are running under Xen, we MUST disable the native SWIOTLB.
43	 * Don't worry about swiotlb_force flag activating the native, as
44	 * the 'swiotlb' flag is the only one turning it on. */
45	swiotlb = 0;
46
47#ifdef CONFIG_X86_64
48	/* pci_swiotlb_detect_4gb turns on native SWIOTLB if no_iommu == 0
49	 * (so no iommu=X command line over-writes).
50	 * Considering that PV guests do not want the *native SWIOTLB* but
51	 * only Xen SWIOTLB it is not useful to us so set no_iommu=1 here.
52	 */
53	if (max_pfn > MAX_DMA32_PFN)
54		no_iommu = 1;
55#endif
56	return xen_swiotlb;
57}
58
59void __init pci_xen_swiotlb_init(void)
60{
61	if (xen_swiotlb) {
62		xen_swiotlb_init(1, true /* early */);
63		dma_ops = &xen_swiotlb_dma_ops;
64
65#ifdef CONFIG_PCI
66		/* Make sure ACS will be enabled */
67		pci_request_acs();
68#endif
69	}
70}
71
72int pci_xen_swiotlb_init_late(void)
73{
74	int rc;
75
76	if (xen_swiotlb)
77		return 0;
78
79	rc = xen_swiotlb_init(1, false /* late */);
80	if (rc)
81		return rc;
82
83	dma_ops = &xen_swiotlb_dma_ops;
84#ifdef CONFIG_PCI
85	/* Make sure ACS will be enabled */
86	pci_request_acs();
87#endif
88
89	return 0;
90}
91EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
92
93IOMMU_INIT_FINISH(pci_xen_swiotlb_detect,
94		  NULL,
95		  pci_xen_swiotlb_init,
96		  NULL);
97