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- // SPDX-License-Identifier: GPL-2.0
- #include <linux/dma-map-ops.h>
- #include <linux/dma-direct.h>
- #include <linux/iommu.h>
- #include <linux/dmar.h>
- #include <linux/export.h>
- #include <linux/memblock.h>
- #include <linux/gfp.h>
- #include <linux/pci.h>
- #include <linux/amd-iommu.h>
- #include <asm/proto.h>
- #include <asm/dma.h>
- #include <asm/iommu.h>
- #include <asm/gart.h>
- #include <asm/x86_init.h>
- #include <xen/xen.h>
- #include <xen/swiotlb-xen.h>
- static bool disable_dac_quirk __read_mostly;
- const struct dma_map_ops *dma_ops;
- EXPORT_SYMBOL(dma_ops);
- #ifdef CONFIG_IOMMU_DEBUG
- int panic_on_overflow __read_mostly = 1;
- int force_iommu __read_mostly = 1;
- #else
- int panic_on_overflow __read_mostly = 0;
- int force_iommu __read_mostly = 0;
- #endif
- int iommu_merge __read_mostly = 0;
- int no_iommu __read_mostly;
- /* Set this to 1 if there is a HW IOMMU in the system */
- int iommu_detected __read_mostly = 0;
- #ifdef CONFIG_SWIOTLB
- bool x86_swiotlb_enable;
- static unsigned int x86_swiotlb_flags;
- static void __init pci_swiotlb_detect(void)
- {
- /* don't initialize swiotlb if iommu=off (no_iommu=1) */
- if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN)
- x86_swiotlb_enable = true;
- /*
- * Set swiotlb to 1 so that bounce buffers are allocated and used for
- * devices that can't support DMA to encrypted memory.
- */
- if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT))
- x86_swiotlb_enable = true;
- /*
- * Guest with guest memory encryption currently perform all DMA through
- * bounce buffers as the hypervisor can't access arbitrary VM memory
- * that is not explicitly shared with it.
- */
- if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) {
- x86_swiotlb_enable = true;
- x86_swiotlb_flags |= SWIOTLB_FORCE;
- }
- }
- #else
- static inline void __init pci_swiotlb_detect(void)
- {
- }
- #define x86_swiotlb_flags 0
- #endif /* CONFIG_SWIOTLB */
- #ifdef CONFIG_SWIOTLB_XEN
- static void __init pci_xen_swiotlb_init(void)
- {
- if (!xen_initial_domain() && !x86_swiotlb_enable)
- return;
- x86_swiotlb_enable = true;
- x86_swiotlb_flags |= SWIOTLB_ANY;
- swiotlb_init_remap(true, x86_swiotlb_flags, xen_swiotlb_fixup);
- dma_ops = &xen_swiotlb_dma_ops;
- if (IS_ENABLED(CONFIG_PCI))
- pci_request_acs();
- }
- int pci_xen_swiotlb_init_late(void)
- {
- if (dma_ops == &xen_swiotlb_dma_ops)
- return 0;
- /* we can work with the default swiotlb */
- if (!io_tlb_default_mem.nslabs) {
- int rc = swiotlb_init_late(swiotlb_size_or_default(),
- GFP_KERNEL, xen_swiotlb_fixup);
- if (rc < 0)
- return rc;
- }
- /* XXX: this switches the dma ops under live devices! */
- dma_ops = &xen_swiotlb_dma_ops;
- if (IS_ENABLED(CONFIG_PCI))
- pci_request_acs();
- return 0;
- }
- EXPORT_SYMBOL_GPL(pci_xen_swiotlb_init_late);
- #else
- static inline void __init pci_xen_swiotlb_init(void)
- {
- }
- #endif /* CONFIG_SWIOTLB_XEN */
- void __init pci_iommu_alloc(void)
- {
- if (xen_pv_domain()) {
- pci_xen_swiotlb_init();
- return;
- }
- pci_swiotlb_detect();
- gart_iommu_hole_init();
- amd_iommu_detect();
- detect_intel_iommu();
- swiotlb_init(x86_swiotlb_enable, x86_swiotlb_flags);
- }
- /*
- * See <Documentation/x86/x86_64/boot-options.rst> for the iommu kernel
- * parameter documentation.
- */
- static __init int iommu_setup(char *p)
- {
- iommu_merge = 1;
- if (!p)
- return -EINVAL;
- while (*p) {
- if (!strncmp(p, "off", 3))
- no_iommu = 1;
- /* gart_parse_options has more force support */
- if (!strncmp(p, "force", 5))
- force_iommu = 1;
- if (!strncmp(p, "noforce", 7)) {
- iommu_merge = 0;
- force_iommu = 0;
- }
- if (!strncmp(p, "biomerge", 8)) {
- iommu_merge = 1;
- force_iommu = 1;
- }
- if (!strncmp(p, "panic", 5))
- panic_on_overflow = 1;
- if (!strncmp(p, "nopanic", 7))
- panic_on_overflow = 0;
- if (!strncmp(p, "merge", 5)) {
- iommu_merge = 1;
- force_iommu = 1;
- }
- if (!strncmp(p, "nomerge", 7))
- iommu_merge = 0;
- if (!strncmp(p, "forcesac", 8))
- pr_warn("forcesac option ignored.\n");
- if (!strncmp(p, "allowdac", 8))
- pr_warn("allowdac option ignored.\n");
- if (!strncmp(p, "nodac", 5))
- pr_warn("nodac option ignored.\n");
- if (!strncmp(p, "usedac", 6)) {
- disable_dac_quirk = true;
- return 1;
- }
- #ifdef CONFIG_SWIOTLB
- if (!strncmp(p, "soft", 4))
- x86_swiotlb_enable = true;
- #endif
- if (!strncmp(p, "pt", 2))
- iommu_set_default_passthrough(true);
- if (!strncmp(p, "nopt", 4))
- iommu_set_default_translated(true);
- gart_parse_options(p);
- p += strcspn(p, ",");
- if (*p == ',')
- ++p;
- }
- return 0;
- }
- early_param("iommu", iommu_setup);
- static int __init pci_iommu_init(void)
- {
- x86_init.iommu.iommu_init();
- #ifdef CONFIG_SWIOTLB
- /* An IOMMU turned us off. */
- if (x86_swiotlb_enable) {
- pr_info("PCI-DMA: Using software bounce buffering for IO (SWIOTLB)\n");
- swiotlb_print_info();
- } else {
- swiotlb_exit();
- }
- #endif
- return 0;
- }
- /* Must execute after PCI subsystem */
- rootfs_initcall(pci_iommu_init);
- #ifdef CONFIG_PCI
- /* Many VIA bridges seem to corrupt data for DAC. Disable it here */
- static int via_no_dac_cb(struct pci_dev *pdev, void *data)
- {
- pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
- return 0;
- }
- static void via_no_dac(struct pci_dev *dev)
- {
- if (!disable_dac_quirk) {
- dev_info(&dev->dev, "disabling DAC on VIA PCI bridge\n");
- pci_walk_bus(dev->subordinate, via_no_dac_cb, NULL);
- }
- }
- DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID,
- PCI_CLASS_BRIDGE_PCI, 8, via_no_dac);
- #endif
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