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1// SPDX-License-Identifier: GPL-2.02/*3 * Virtual I/O topology4 *5 * The Virtual I/O Translation Table (VIOT) describes the topology of6 * para-virtual IOMMUs and the endpoints they manage. The OS uses it to7 * initialize devices in the right order, preventing endpoints from issuing DMA8 * before their IOMMU is ready.9 *10 * When binding a driver to a device, before calling the device driver's probe()11 * method, the driver infrastructure calls dma_configure(). At that point the12 * VIOT driver looks for an IOMMU associated to the device in the VIOT table.13 * If an IOMMU exists and has been initialized, the VIOT driver initializes the14 * device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU15 * ops when the device driver configures DMA mappings. If an IOMMU exists and16 * hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing17 * the device until the IOMMU is available.18 */19#define pr_fmt(fmt) "ACPI: VIOT: " fmt20 21#include <linux/acpi_viot.h>22#include <linux/fwnode.h>23#include <linux/iommu.h>24#include <linux/list.h>25#include <linux/pci.h>26#include <linux/platform_device.h>27 28struct viot_iommu {29 /* Node offset within the table */30 unsigned int offset;31 struct fwnode_handle *fwnode;32 struct list_head list;33};34 35struct viot_endpoint {36 union {37 /* PCI range */38 struct {39 u16 segment_start;40 u16 segment_end;41 u16 bdf_start;42 u16 bdf_end;43 };44 /* MMIO */45 u64 address;46 };47 u32 endpoint_id;48 struct viot_iommu *viommu;49 struct list_head list;50};51 52static struct acpi_table_viot *viot;53static LIST_HEAD(viot_iommus);54static LIST_HEAD(viot_pci_ranges);55static LIST_HEAD(viot_mmio_endpoints);56 57static int __init viot_check_bounds(const struct acpi_viot_header *hdr)58{59 struct acpi_viot_header *start, *end, *hdr_end;60 61 start = ACPI_ADD_PTR(struct acpi_viot_header, viot,62 max_t(size_t, sizeof(*viot), viot->node_offset));63 end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length);64 hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr));65 66 if (hdr < start || hdr_end > end) {67 pr_err(FW_BUG "Node pointer overflows\n");68 return -EOVERFLOW;69 }70 if (hdr->length < sizeof(*hdr)) {71 pr_err(FW_BUG "Empty node\n");72 return -EINVAL;73 }74 return 0;75}76 77static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu,78 u16 segment, u16 bdf)79{80 struct pci_dev *pdev;81 struct fwnode_handle *fwnode;82 83 pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf),84 bdf & 0xff);85 if (!pdev) {86 pr_err("Could not find PCI IOMMU\n");87 return -ENODEV;88 }89 90 fwnode = dev_fwnode(&pdev->dev);91 if (!fwnode) {92 /*93 * PCI devices aren't necessarily described by ACPI. Create a94 * fwnode so the IOMMU subsystem can identify this device.95 */96 fwnode = acpi_alloc_fwnode_static();97 if (!fwnode) {98 pci_dev_put(pdev);99 return -ENOMEM;100 }101 set_primary_fwnode(&pdev->dev, fwnode);102 }103 viommu->fwnode = dev_fwnode(&pdev->dev);104 pci_dev_put(pdev);105 return 0;106}107 108static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu,109 u64 address)110{111 struct acpi_device *adev;112 struct resource res = {113 .start = address,114 .end = address,115 .flags = IORESOURCE_MEM,116 };117 118 adev = acpi_resource_consumer(&res);119 if (!adev) {120 pr_err("Could not find MMIO IOMMU\n");121 return -EINVAL;122 }123 viommu->fwnode = &adev->fwnode;124 return 0;125}126 127static struct viot_iommu * __init viot_get_iommu(unsigned int offset)128{129 int ret;130 struct viot_iommu *viommu;131 struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header,132 viot, offset);133 union {134 struct acpi_viot_virtio_iommu_pci pci;135 struct acpi_viot_virtio_iommu_mmio mmio;136 } *node = (void *)hdr;137 138 list_for_each_entry(viommu, &viot_iommus, list)139 if (viommu->offset == offset)140 return viommu;141 142 if (viot_check_bounds(hdr))143 return NULL;144 145 viommu = kzalloc(sizeof(*viommu), GFP_KERNEL);146 if (!viommu)147 return NULL;148 149 viommu->offset = offset;150 switch (hdr->type) {151 case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI:152 if (hdr->length < sizeof(node->pci))153 goto err_free;154 155 ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment,156 node->pci.bdf);157 break;158 case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO:159 if (hdr->length < sizeof(node->mmio))160 goto err_free;161 162 ret = viot_get_mmio_iommu_fwnode(viommu,163 node->mmio.base_address);164 break;165 default:166 ret = -EINVAL;167 }168 if (ret)169 goto err_free;170 171 list_add(&viommu->list, &viot_iommus);172 return viommu;173 174err_free:175 kfree(viommu);176 return NULL;177}178 179static int __init viot_parse_node(const struct acpi_viot_header *hdr)180{181 int ret = -EINVAL;182 struct list_head *list;183 struct viot_endpoint *ep;184 union {185 struct acpi_viot_mmio mmio;186 struct acpi_viot_pci_range pci;187 } *node = (void *)hdr;188 189 if (viot_check_bounds(hdr))190 return -EINVAL;191 192 if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI ||193 hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO)194 return 0;195 196 ep = kzalloc(sizeof(*ep), GFP_KERNEL);197 if (!ep)198 return -ENOMEM;199 200 switch (hdr->type) {201 case ACPI_VIOT_NODE_PCI_RANGE:202 if (hdr->length < sizeof(node->pci)) {203 pr_err(FW_BUG "Invalid PCI node size\n");204 goto err_free;205 }206 207 ep->segment_start = node->pci.segment_start;208 ep->segment_end = node->pci.segment_end;209 ep->bdf_start = node->pci.bdf_start;210 ep->bdf_end = node->pci.bdf_end;211 ep->endpoint_id = node->pci.endpoint_start;212 ep->viommu = viot_get_iommu(node->pci.output_node);213 list = &viot_pci_ranges;214 break;215 case ACPI_VIOT_NODE_MMIO:216 if (hdr->length < sizeof(node->mmio)) {217 pr_err(FW_BUG "Invalid MMIO node size\n");218 goto err_free;219 }220 221 ep->address = node->mmio.base_address;222 ep->endpoint_id = node->mmio.endpoint;223 ep->viommu = viot_get_iommu(node->mmio.output_node);224 list = &viot_mmio_endpoints;225 break;226 default:227 pr_warn("Unsupported node %x\n", hdr->type);228 ret = 0;229 goto err_free;230 }231 232 if (!ep->viommu) {233 pr_warn("No IOMMU node found\n");234 /*235 * A future version of the table may use the node for other236 * purposes. Keep parsing.237 */238 ret = 0;239 goto err_free;240 }241 242 list_add(&ep->list, list);243 return 0;244 245err_free:246 kfree(ep);247 return ret;248}249 250/**251 * acpi_viot_early_init - Test the presence of VIOT and enable ACS252 *253 * If the VIOT does exist, ACS must be enabled. This cannot be254 * done in acpi_viot_init() which is called after the bus scan255 */256void __init acpi_viot_early_init(void)257{258#ifdef CONFIG_PCI259 acpi_status status;260 struct acpi_table_header *hdr;261 262 status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);263 if (ACPI_FAILURE(status))264 return;265 pci_request_acs();266 acpi_put_table(hdr);267#endif268}269 270/**271 * acpi_viot_init - Parse the VIOT table272 *273 * Parse the VIOT table, prepare the list of endpoints to be used during DMA274 * setup of devices.275 */276void __init acpi_viot_init(void)277{278 int i;279 acpi_status status;280 struct acpi_table_header *hdr;281 struct acpi_viot_header *node;282 283 status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr);284 if (ACPI_FAILURE(status)) {285 if (status != AE_NOT_FOUND) {286 const char *msg = acpi_format_exception(status);287 288 pr_err("Failed to get table, %s\n", msg);289 }290 return;291 }292 293 viot = (void *)hdr;294 295 node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset);296 for (i = 0; i < viot->node_count; i++) {297 if (viot_parse_node(node))298 return;299 300 node = ACPI_ADD_PTR(struct acpi_viot_header, node,301 node->length);302 }303 304 acpi_put_table(hdr);305}306 307static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu,308 u32 epid)309{310 if (!viommu || !IS_ENABLED(CONFIG_VIRTIO_IOMMU))311 return -ENODEV;312 313 /* We're not translating ourself */314 if (device_match_fwnode(dev, viommu->fwnode))315 return -EINVAL;316 317 return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode);318}319 320static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data)321{322 u32 epid;323 struct viot_endpoint *ep;324 struct device *aliased_dev = data;325 u32 domain_nr = pci_domain_nr(pdev->bus);326 327 list_for_each_entry(ep, &viot_pci_ranges, list) {328 if (domain_nr >= ep->segment_start &&329 domain_nr <= ep->segment_end &&330 dev_id >= ep->bdf_start &&331 dev_id <= ep->bdf_end) {332 epid = ((domain_nr - ep->segment_start) << 16) +333 dev_id - ep->bdf_start + ep->endpoint_id;334 335 return viot_dev_iommu_init(aliased_dev, ep->viommu,336 epid);337 }338 }339 return -ENODEV;340}341 342static int viot_mmio_dev_iommu_init(struct platform_device *pdev)343{344 struct resource *mem;345 struct viot_endpoint *ep;346 347 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);348 if (!mem)349 return -ENODEV;350 351 list_for_each_entry(ep, &viot_mmio_endpoints, list) {352 if (ep->address == mem->start)353 return viot_dev_iommu_init(&pdev->dev, ep->viommu,354 ep->endpoint_id);355 }356 return -ENODEV;357}358 359/**360 * viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT361 * @dev: the endpoint362 *363 * Return: 0 on success, <0 on failure364 */365int viot_iommu_configure(struct device *dev)366{367 if (dev_is_pci(dev))368 return pci_for_each_dma_alias(to_pci_dev(dev),369 viot_pci_dev_iommu_init, dev);370 else if (dev_is_platform(dev))371 return viot_mmio_dev_iommu_init(to_platform_device(dev));372 return -ENODEV;373}374