diff options
Diffstat (limited to 'drivers/acpi/viot.c')
| -rw-r--r-- | drivers/acpi/viot.c | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/drivers/acpi/viot.c b/drivers/acpi/viot.c new file mode 100644 index 0000000000..c8025921c1 --- /dev/null +++ b/drivers/acpi/viot.c @@ -0,0 +1,380 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Virtual I/O topology + * + * The Virtual I/O Translation Table (VIOT) describes the topology of + * para-virtual IOMMUs and the endpoints they manage. The OS uses it to + * initialize devices in the right order, preventing endpoints from issuing DMA + * before their IOMMU is ready. + * + * When binding a driver to a device, before calling the device driver's probe() + * method, the driver infrastructure calls dma_configure(). At that point the + * VIOT driver looks for an IOMMU associated to the device in the VIOT table. + * If an IOMMU exists and has been initialized, the VIOT driver initializes the + * device's IOMMU fwspec, allowing the DMA infrastructure to invoke the IOMMU + * ops when the device driver configures DMA mappings. If an IOMMU exists and + * hasn't yet been initialized, VIOT returns -EPROBE_DEFER to postpone probing + * the device until the IOMMU is available. + */ +#define pr_fmt(fmt) "ACPI: VIOT: " fmt + +#include <linux/acpi_viot.h> +#include <linux/fwnode.h> +#include <linux/iommu.h> +#include <linux/list.h> +#include <linux/pci.h> +#include <linux/platform_device.h> + +struct viot_iommu { + /* Node offset within the table */ + unsigned int offset; + struct fwnode_handle *fwnode; + struct list_head list; +}; + +struct viot_endpoint { + union { + /* PCI range */ + struct { + u16 segment_start; + u16 segment_end; + u16 bdf_start; + u16 bdf_end; + }; + /* MMIO */ + u64 address; + }; + u32 endpoint_id; + struct viot_iommu *viommu; + struct list_head list; +}; + +static struct acpi_table_viot *viot; +static LIST_HEAD(viot_iommus); +static LIST_HEAD(viot_pci_ranges); +static LIST_HEAD(viot_mmio_endpoints); + +static int __init viot_check_bounds(const struct acpi_viot_header *hdr) +{ + struct acpi_viot_header *start, *end, *hdr_end; + + start = ACPI_ADD_PTR(struct acpi_viot_header, viot, + max_t(size_t, sizeof(*viot), viot->node_offset)); + end = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->header.length); + hdr_end = ACPI_ADD_PTR(struct acpi_viot_header, hdr, sizeof(*hdr)); + + if (hdr < start || hdr_end > end) { + pr_err(FW_BUG "Node pointer overflows\n"); + return -EOVERFLOW; + } + if (hdr->length < sizeof(*hdr)) { + pr_err(FW_BUG "Empty node\n"); + return -EINVAL; + } + return 0; +} + +static int __init viot_get_pci_iommu_fwnode(struct viot_iommu *viommu, + u16 segment, u16 bdf) +{ + struct pci_dev *pdev; + struct fwnode_handle *fwnode; + + pdev = pci_get_domain_bus_and_slot(segment, PCI_BUS_NUM(bdf), + bdf & 0xff); + if (!pdev) { + pr_err("Could not find PCI IOMMU\n"); + return -ENODEV; + } + + fwnode = dev_fwnode(&pdev->dev); + if (!fwnode) { + /* + * PCI devices aren't necessarily described by ACPI. Create a + * fwnode so the IOMMU subsystem can identify this device. + */ + fwnode = acpi_alloc_fwnode_static(); + if (!fwnode) { + pci_dev_put(pdev); + return -ENOMEM; + } + set_primary_fwnode(&pdev->dev, fwnode); + } + viommu->fwnode = dev_fwnode(&pdev->dev); + pci_dev_put(pdev); + return 0; +} + +static int __init viot_get_mmio_iommu_fwnode(struct viot_iommu *viommu, + u64 address) +{ + struct acpi_device *adev; + struct resource res = { + .start = address, + .end = address, + .flags = IORESOURCE_MEM, + }; + + adev = acpi_resource_consumer(&res); + if (!adev) { + pr_err("Could not find MMIO IOMMU\n"); + return -EINVAL; + } + viommu->fwnode = &adev->fwnode; + return 0; +} + +static struct viot_iommu * __init viot_get_iommu(unsigned int offset) +{ + int ret; + struct viot_iommu *viommu; + struct acpi_viot_header *hdr = ACPI_ADD_PTR(struct acpi_viot_header, + viot, offset); + union { + struct acpi_viot_virtio_iommu_pci pci; + struct acpi_viot_virtio_iommu_mmio mmio; + } *node = (void *)hdr; + + list_for_each_entry(viommu, &viot_iommus, list) + if (viommu->offset == offset) + return viommu; + + if (viot_check_bounds(hdr)) + return NULL; + + viommu = kzalloc(sizeof(*viommu), GFP_KERNEL); + if (!viommu) + return NULL; + + viommu->offset = offset; + switch (hdr->type) { + case ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI: + if (hdr->length < sizeof(node->pci)) + goto err_free; + + ret = viot_get_pci_iommu_fwnode(viommu, node->pci.segment, + node->pci.bdf); + break; + case ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO: + if (hdr->length < sizeof(node->mmio)) + goto err_free; + + ret = viot_get_mmio_iommu_fwnode(viommu, + node->mmio.base_address); + break; + default: + ret = -EINVAL; + } + if (ret) + goto err_free; + + list_add(&viommu->list, &viot_iommus); + return viommu; + +err_free: + kfree(viommu); + return NULL; +} + +static int __init viot_parse_node(const struct acpi_viot_header *hdr) +{ + int ret = -EINVAL; + struct list_head *list; + struct viot_endpoint *ep; + union { + struct acpi_viot_mmio mmio; + struct acpi_viot_pci_range pci; + } *node = (void *)hdr; + + if (viot_check_bounds(hdr)) + return -EINVAL; + + if (hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_PCI || + hdr->type == ACPI_VIOT_NODE_VIRTIO_IOMMU_MMIO) + return 0; + + ep = kzalloc(sizeof(*ep), GFP_KERNEL); + if (!ep) + return -ENOMEM; + + switch (hdr->type) { + case ACPI_VIOT_NODE_PCI_RANGE: + if (hdr->length < sizeof(node->pci)) { + pr_err(FW_BUG "Invalid PCI node size\n"); + goto err_free; + } + + ep->segment_start = node->pci.segment_start; + ep->segment_end = node->pci.segment_end; + ep->bdf_start = node->pci.bdf_start; + ep->bdf_end = node->pci.bdf_end; + ep->endpoint_id = node->pci.endpoint_start; + ep->viommu = viot_get_iommu(node->pci.output_node); + list = &viot_pci_ranges; + break; + case ACPI_VIOT_NODE_MMIO: + if (hdr->length < sizeof(node->mmio)) { + pr_err(FW_BUG "Invalid MMIO node size\n"); + goto err_free; + } + + ep->address = node->mmio.base_address; + ep->endpoint_id = node->mmio.endpoint; + ep->viommu = viot_get_iommu(node->mmio.output_node); + list = &viot_mmio_endpoints; + break; + default: + pr_warn("Unsupported node %x\n", hdr->type); + ret = 0; + goto err_free; + } + + if (!ep->viommu) { + pr_warn("No IOMMU node found\n"); + /* + * A future version of the table may use the node for other + * purposes. Keep parsing. + */ + ret = 0; + goto err_free; + } + + list_add(&ep->list, list); + return 0; + +err_free: + kfree(ep); + return ret; +} + +/** + * acpi_viot_early_init - Test the presence of VIOT and enable ACS + * + * If the VIOT does exist, ACS must be enabled. This cannot be + * done in acpi_viot_init() which is called after the bus scan + */ +void __init acpi_viot_early_init(void) +{ +#ifdef CONFIG_PCI + acpi_status status; + struct acpi_table_header *hdr; + + status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr); + if (ACPI_FAILURE(status)) + return; + pci_request_acs(); + acpi_put_table(hdr); +#endif +} + +/** + * acpi_viot_init - Parse the VIOT table + * + * Parse the VIOT table, prepare the list of endpoints to be used during DMA + * setup of devices. + */ +void __init acpi_viot_init(void) +{ + int i; + acpi_status status; + struct acpi_table_header *hdr; + struct acpi_viot_header *node; + + status = acpi_get_table(ACPI_SIG_VIOT, 0, &hdr); + if (ACPI_FAILURE(status)) { + if (status != AE_NOT_FOUND) { + const char *msg = acpi_format_exception(status); + + pr_err("Failed to get table, %s\n", msg); + } + return; + } + + viot = (void *)hdr; + + node = ACPI_ADD_PTR(struct acpi_viot_header, viot, viot->node_offset); + for (i = 0; i < viot->node_count; i++) { + if (viot_parse_node(node)) + return; + + node = ACPI_ADD_PTR(struct acpi_viot_header, node, + node->length); + } + + acpi_put_table(hdr); +} + +static int viot_dev_iommu_init(struct device *dev, struct viot_iommu *viommu, + u32 epid) +{ + const struct iommu_ops *ops; + + if (!viommu) + return -ENODEV; + + /* We're not translating ourself */ + if (device_match_fwnode(dev, viommu->fwnode)) + return -EINVAL; + + ops = iommu_ops_from_fwnode(viommu->fwnode); + if (!ops) + return IS_ENABLED(CONFIG_VIRTIO_IOMMU) ? + -EPROBE_DEFER : -ENODEV; + + return acpi_iommu_fwspec_init(dev, epid, viommu->fwnode, ops); +} + +static int viot_pci_dev_iommu_init(struct pci_dev *pdev, u16 dev_id, void *data) +{ + u32 epid; + struct viot_endpoint *ep; + struct device *aliased_dev = data; + u32 domain_nr = pci_domain_nr(pdev->bus); + + list_for_each_entry(ep, &viot_pci_ranges, list) { + if (domain_nr >= ep->segment_start && + domain_nr <= ep->segment_end && + dev_id >= ep->bdf_start && + dev_id <= ep->bdf_end) { + epid = ((domain_nr - ep->segment_start) << 16) + + dev_id - ep->bdf_start + ep->endpoint_id; + + return viot_dev_iommu_init(aliased_dev, ep->viommu, + epid); + } + } + return -ENODEV; +} + +static int viot_mmio_dev_iommu_init(struct platform_device *pdev) +{ + struct resource *mem; + struct viot_endpoint *ep; + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!mem) + return -ENODEV; + + list_for_each_entry(ep, &viot_mmio_endpoints, list) { + if (ep->address == mem->start) + return viot_dev_iommu_init(&pdev->dev, ep->viommu, + ep->endpoint_id); + } + return -ENODEV; +} + +/** + * viot_iommu_configure - Setup IOMMU ops for an endpoint described by VIOT + * @dev: the endpoint + * + * Return: 0 on success, <0 on failure + */ +int viot_iommu_configure(struct device *dev) +{ + if (dev_is_pci(dev)) + return pci_for_each_dma_alias(to_pci_dev(dev), + viot_pci_dev_iommu_init, dev); + else if (dev_is_platform(dev)) + return viot_mmio_dev_iommu_init(to_platform_device(dev)); + return -ENODEV; +} |