1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/dma-map-ops.h>
3 #include <linux/dma-direct.h>
4 #include <linux/iommu.h>
5 #include <linux/dmar.h>
6 #include <linux/export.h>
7 #include <linux/memblock.h>
10 #include <linux/amd-iommu.h>
12 #include <asm/proto.h>
14 #include <asm/iommu.h>
16 #include <asm/x86_init.h>
19 #include <xen/swiotlb-xen.h>
21 static bool disable_dac_quirk __read_mostly;
23 const struct dma_map_ops *dma_ops;
24 EXPORT_SYMBOL(dma_ops);
26 #ifdef CONFIG_IOMMU_DEBUG
27 int panic_on_overflow __read_mostly = 1;
28 int force_iommu __read_mostly = 1;
30 int panic_on_overflow __read_mostly = 0;
31 int force_iommu __read_mostly = 0;
34 int iommu_merge __read_mostly = 0;
36 int no_iommu __read_mostly;
37 /* Set this to 1 if there is a HW IOMMU in the system */
38 int iommu_detected __read_mostly = 0;
41 bool x86_swiotlb_enable;
42 static unsigned int x86_swiotlb_flags;
44 static void __init pci_swiotlb_detect(void)
46 /* don't initialize swiotlb if iommu=off (no_iommu=1) */
47 if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
48 x86_swiotlb_enable = true;
51 * Set swiotlb to 1 so that bounce buffers are allocated and used for
52 * devices that can't support DMA to encrypted memory.
54 if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
55 x86_swiotlb_enable = true;
58 * Guest with guest memory encryption currently perform all DMA through
59 * bounce buffers as the hypervisor can't access arbitrary VM memory
60 * that is not explicitly shared with it.
62 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
63 x86_swiotlb_enable = true;
64 x86_swiotlb_flags |= SWIOTLB_FORCE;
68 static inline void __init pci_swiotlb_detect(void)
71 #define x86_swiotlb_flags 0
72 #endif /* CONFIG_SWIOTLB */
74 #ifdef CONFIG_SWIOTLB_XEN
75 static void __init pci_xen_swiotlb_init(void)
77 if (!xen_initial_domain() && !x86_swiotlb_enable)
79 x86_swiotlb_enable = true;
80 x86_swiotlb_flags |= SWIOTLB_ANY;
81 swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
82 dma_ops = &xen_swiotlb_dma_ops;
83 if (IS_ENABLED(CONFIG_PCI))
87 int pci_xen_swiotlb_init_late(void)
89 if (dma_ops == &xen_swiotlb_dma_ops)
92 /* we can work with the default swiotlb */
93 if (!io_tlb_default_mem.nslabs) {
94 int rc = swiotlb_init_late(swiotlb_size_or_default(),
95 GFP_KERNEL, xen_swiotlb_fixup);
100 /* XXX: this switches the dma ops under live devices! */
101 dma_ops = &xen_swiotlb_dma_ops;
102 if (IS_ENABLED(CONFIG_PCI))
106 EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
108 static inline void __init pci_xen_swiotlb_init(void)
111 #endif /* CONFIG_SWIOTLB_XEN */
113 void __init pci_iommu_alloc(void)
115 if (xen_pv_domain()) {
116 pci_xen_swiotlb_init();
119 pci_swiotlb_detect();
120 gart_iommu_hole_init();
122 detect_intel_iommu();
123 swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
127 * See <Documentation/x86/x86_64/boot-options.rst> for the iommu kernel
128 * parameter documentation.
130 static __init int iommu_setup(char *p)
138 if (!strncmp(p, "off", 3))
140 /* gart_parse_options has more force support */
141 if (!strncmp(p, "force", 5))
143 if (!strncmp(p, "noforce", 7)) {
148 if (!strncmp(p, "biomerge", 8)) {
152 if (!strncmp(p, "panic", 5))
153 panic_on_overflow = 1;
154 if (!strncmp(p, "nopanic", 7))
155 panic_on_overflow = 0;
156 if (!strncmp(p, "merge", 5)) {
160 if (!strncmp(p, "nomerge", 7))
162 if (!strncmp(p, "forcesac", 8))
163 pr_warn("forcesac option ignored.\n");
164 if (!strncmp(p, "allowdac", 8))
165 pr_warn("allowdac option ignored.\n");
166 if (!strncmp(p, "nodac", 5))
167 pr_warn("nodac option ignored.\n");
168 if (!strncmp(p, "usedac", 6)) {
169 disable_dac_quirk = true;
172 #ifdef CONFIG_SWIOTLB
173 if (!strncmp(p, "soft", 4))
174 x86_swiotlb_enable = true;
176 if (!strncmp(p, "pt", 2))
177 iommu_set_default_passthrough(true);
178 if (!strncmp(p, "nopt", 4))
179 iommu_set_default_translated(true);
181 gart_parse_options(p);
183 p += strcspn(p, ",");
189 early_param("iommu", iommu_setup);
191 static int __init pci_iommu_init(void)
193 x86_init.iommu.iommu_init();
195 #ifdef CONFIG_SWIOTLB
196 /* An IOMMU turned us off. */
197 if (x86_swiotlb_enable) {
198 pr_info("PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
199 swiotlb_print_info();
207 /* Must execute after PCI subsystem */
208 rootfs_initcall(pci_iommu_init);
211 /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
213 static int via_no_dac_cb(struct pci_dev *pdev, void *data)
215 pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
219 static void via_no_dac(struct pci_dev *dev)
221 if (!disable_dac_quirk) {
222 dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
223 pci_walk_bus(dev->subordinate, via_no_dac_cb, NULL);
226 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
227 PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);